The DB9 tail light loop
Discussion
Somehow there must be a way out of this loop.
I bought the car (2007) in Oct 2021. There was condensation in the NSR tail light. Dealer did the 'yeah just washed it' routine.
2-3 months later, when I used the brakes when the lights were on, I got a dashboard warning 'check brake lights'. Eventually, the car went back to the dealer for another matter, and he swapped the unit out for a s/h one.
All worked well for about a year. Then I got a 'check indicator light' warning. I took the car to my local mechanic fondly thinking it's a simple fix. Just a bulb, right? Ah no, he says the tail unit is full of water and I need another one.
I find a chap who repairs DB9 tail lights. He sounds very confident on the phone so off it goes to him. £310 later it comes back. I'm not convinced it's the same unit I sent, but anyway, it is fitted.
Immediately I notice that when I have the radio on and indicate left, I hear static in time with the indicator. Well b
ks, I am tired of getting this unit changed, now its third in <18 months, so I will live with it.
And then today, when braking in daylight, I get 'check brake lights' again. Later, when it's dark, I nip out for some fish and chips, and whilst waiting, with the sidelights on, I notice the left one is brighter:
I'm not sure if it's the tail light or the brake light - perhaps they are both on together - but I'm back to where I started.
I can:
1) Send the unit back to the bloke who said he'd fixed it because he says his work is warranted. It will still cost me £75 shipping and maybe that's not the problem.
2) Take it to a very good autoelectrician for a proper diagnosis, which will cost more than £75, and he may just say 'the tail light is borked'.
3) I can't think of a 3.
What does the panel think?
I bought the car (2007) in Oct 2021. There was condensation in the NSR tail light. Dealer did the 'yeah just washed it' routine.
2-3 months later, when I used the brakes when the lights were on, I got a dashboard warning 'check brake lights'. Eventually, the car went back to the dealer for another matter, and he swapped the unit out for a s/h one.
All worked well for about a year. Then I got a 'check indicator light' warning. I took the car to my local mechanic fondly thinking it's a simple fix. Just a bulb, right? Ah no, he says the tail unit is full of water and I need another one.
I find a chap who repairs DB9 tail lights. He sounds very confident on the phone so off it goes to him. £310 later it comes back. I'm not convinced it's the same unit I sent, but anyway, it is fitted.
Immediately I notice that when I have the radio on and indicate left, I hear static in time with the indicator. Well b
ks, I am tired of getting this unit changed, now its third in <18 months, so I will live with it.And then today, when braking in daylight, I get 'check brake lights' again. Later, when it's dark, I nip out for some fish and chips, and whilst waiting, with the sidelights on, I notice the left one is brighter:
I'm not sure if it's the tail light or the brake light - perhaps they are both on together - but I'm back to where I started.
I can:
1) Send the unit back to the bloke who said he'd fixed it because he says his work is warranted. It will still cost me £75 shipping and maybe that's not the problem.
2) Take it to a very good autoelectrician for a proper diagnosis, which will cost more than £75, and he may just say 'the tail light is borked'.
3) I can't think of a 3.
What does the panel think?
Think I would go for option 1, although your shipping costs seem a little steep. Other consideration is how it was fitted. These units need to be carefully aligned to the body of the car when fitting, so that the casing of the light is not distorted when the fitting nuts are being tightened, allowing the seal between the lens and the body of the light to remain intact. If you do not have condensation inside the light, this may not be the issue for you though and the fault will be simply electronic.
The connector/cabling and earthing to the light unit is also something to consider. When I had a fault with one of mine, I swapped it over with the one on the opposite side to rule this out. Good luck.
The connector/cabling and earthing to the light unit is also something to consider. When I had a fault with one of mine, I swapped it over with the one on the opposite side to rule this out. Good luck.
Thanks for the reply. I was with the mechanic when he fitted it. It took a lot juggling to get the fit as good as it could be - it didn't seem to have quite the same profile as the hole which is why I suspect it's a different unit - unless in the re-gluing procedure the curvature was affected.
£75 is what DHL want for £1,000 cover - the cost of a new unit if they lose it. Perhaps I was being over-cautious but that's what the man recommended (which was why I was surprised when it came back by Royal Mail!)
Swapping the units over (which would render the car undriveable) and then testing - is that possible single-handed? It's excellent logic but I don't think I can do it, and I'd probably break something else.
£75 is what DHL want for £1,000 cover - the cost of a new unit if they lose it. Perhaps I was being over-cautious but that's what the man recommended (which was why I was surprised when it came back by Royal Mail!)
Swapping the units over (which would render the car undriveable) and then testing - is that possible single-handed? It's excellent logic but I don't think I can do it, and I'd probably break something else.
Simpo Two said:
Thanks for the reply. I was with the mechanic when he fitted it. It took a lot juggling to get the fit as good as it could be - it didn't seem to have quite the same profile as the hole which is why I suspect it's a different unit - unless in the re-gluing procedure the curvature was affected.
£75 is what DHL want for £1,000 cover - the cost of a new unit if they lose it. Perhaps I was being over-cautious but that's what the man recommended (which was why I was surprised when it came back by Royal Mail!)
Swapping the units over (which would render the car undriveable) and then testing - is that possible single-handed? It's excellent logic but I don't think I can do it, and I'd probably break something else.
It is quite straightforward to take out the rear lights. I’ve done it and I’m rubbish at this sort of thing. There’s youtube videos on how to do it. Pull off the boot seal to then pull back the trim in the boot where the lights are, undo the nuts and the lights come away, unclip the connector and you’re done! Just do everything slowly and hold on to the nuts and seals when you take them off so they don’t disappear into the recesses of the bodywork. You could easily have both lights out and back in within a couple of hours without breaking a sweat. The hardest bit is lining them up again when reinstalling.£75 is what DHL want for £1,000 cover - the cost of a new unit if they lose it. Perhaps I was being over-cautious but that's what the man recommended (which was why I was surprised when it came back by Royal Mail!)
Swapping the units over (which would render the car undriveable) and then testing - is that possible single-handed? It's excellent logic but I don't think I can do it, and I'd probably break something else.
I took the left unit out and refitted it when it first started playing up; however my attempted repair didn't work and I rather lost enthusiasm after that.
When the units are plugged in on opposite sides, do they dangle on the wire or can you shove them in the gap temporarily?
I also need to make sure the fault is reproducible; sometimes the car is fine to start with and plays up after a while.
From the photo above, can we be sure the unit is at fault, or could some issue elsewhere - earthing is a popular choice - cause it?
When the units are plugged in on opposite sides, do they dangle on the wire or can you shove them in the gap temporarily?
I also need to make sure the fault is reproducible; sometimes the car is fine to start with and plays up after a while.
From the photo above, can we be sure the unit is at fault, or could some issue elsewhere - earthing is a popular choice - cause it?
From your picture it looks to me that the side lights on both lamps are on and brake light on the LH lamp is also on. Best way to check is to get someone else to sit in the car, put the sidelights on, then put the brakes on, then turn the sidelights off and put the brakes on - you should be able to see what changes. You should also get them to turn on the rear fogs to make sure they are operating as intended. I'd do all of this with sidelights, dipped headlamps and full beams - the headlights shouldn't make any difference but it's as best to know that they don't.You also need to look at the relative brightnesses of the various lamps from side to side - a faulty earth will often give a dimmer light.
As for the cause? That's more difficult to diagnose from a picture. It could be an internal fault in the lamp unit, such that when the connection is for side lights only it's also illuminating the brake light - this is why you need to check brake lights with side lights both on and off, as what actually lights up may give a clue. Swapping the unit over would also be a good idea, as others have said, as if the problem moves with the lamp then it's 99% that the lamp is at fault.
There could be a short in the wiring, so that power to the side light is also getting routed to the brake - it's be interesting to see if power to just the brake light gets routed to the sidelight too and lights that up. It could be a faulty earth, where the earth for the lamp is poor so the power routes back through one of the other lamps to find an earth.
It doesn't look like either fog light is illuminated, but it's be interesting to see if anything else lights up when they are turned on.
If you have a multi-meter and know how to use it you could also take the plug off the back of the lamp and run through the above regime, but this time, with the meter set to 15V DC and the black wire well earthed, probe all of the connectors in the plug to see if the power feed to the plug indicates the same condition. For example, if the multi-meter showed that when sidelights only were on you only had a power supply to the sidelight connector in the plug (as expected) but when the lamp was connected both side and brake lights illuminated, that also indicates that the problem is within the lamp - I hope that's clear.
I will say I've probed many a lamp connector with a multi-meter but never an Aston, so I'm assuming you can access the connectors within the plug the same.
Hope that helps and I've not just spent several paragraphs teaching you to suck eggs.
As for the cause? That's more difficult to diagnose from a picture. It could be an internal fault in the lamp unit, such that when the connection is for side lights only it's also illuminating the brake light - this is why you need to check brake lights with side lights both on and off, as what actually lights up may give a clue. Swapping the unit over would also be a good idea, as others have said, as if the problem moves with the lamp then it's 99% that the lamp is at fault.
There could be a short in the wiring, so that power to the side light is also getting routed to the brake - it's be interesting to see if power to just the brake light gets routed to the sidelight too and lights that up. It could be a faulty earth, where the earth for the lamp is poor so the power routes back through one of the other lamps to find an earth.
It doesn't look like either fog light is illuminated, but it's be interesting to see if anything else lights up when they are turned on.
If you have a multi-meter and know how to use it you could also take the plug off the back of the lamp and run through the above regime, but this time, with the meter set to 15V DC and the black wire well earthed, probe all of the connectors in the plug to see if the power feed to the plug indicates the same condition. For example, if the multi-meter showed that when sidelights only were on you only had a power supply to the sidelight connector in the plug (as expected) but when the lamp was connected both side and brake lights illuminated, that also indicates that the problem is within the lamp - I hope that's clear.
I will say I've probed many a lamp connector with a multi-meter but never an Aston, so I'm assuming you can access the connectors within the plug the same.
Hope that helps and I've not just spent several paragraphs teaching you to suck eggs.
Edited by LTP on Wednesday 5th April 16:17
LTP said:
From your picture it looks to me that the side lights on both lamps are on and brake light on the LH lamp is also on.
That's my thought too, unless LEDs can glow twice as brightly as intended. Can a faulty earth make a brake light come on when the brake isn't applied? And if an earth fault is not in the unit but elsewhere in the car, wouldn't it affect both lights?I've tried everything to make this problem go away, from a replacement unit by the dealer, to getting a mechanic to look at it, to a repair, and the ***ing thing keeps coming back to haunt me.
Sorry to hear your having ongoing issues with your rear lights.
My previous DB9 had clear rear lights and had allsorts of condensation issues, but my current car has red lights and I haven't had any problems, although I don't use it everyday and I try not to drive it in the wet, I'm even very careful with the lights when it's washed and DO NOT clean it with a pressure washer!!
Yours is a difficult issue without having to pay alot of money, the one's for sale on ebay could have a history of condensation etc.
Also there are small rubber washers you need to replace on the mounting bolts everytime the lights are removed/installed.
These Astons do have their issues and your not the only one to be frustrated with ongoing issues, my DB9 has had a fuelling/vacuum issue for the last 18 months and been in and out of AM specialist garages with no success, I have also worked on it myself and it's still ongoing. My power steering pump burn't out after I flushed out the PS fluid using the AM procedure and the Aston 1936 video, I was massively unlucky because although I didn't know it at the time there was trapped air in the system so when I started the car up the pump burnt out. I removed the pump and it's now getting reconditioned as a new one from AM is £1100!!!
Try not to get too down heartened with her, the way I view it is we are very lucky to own these cars!!
Good luck
My previous DB9 had clear rear lights and had allsorts of condensation issues, but my current car has red lights and I haven't had any problems, although I don't use it everyday and I try not to drive it in the wet, I'm even very careful with the lights when it's washed and DO NOT clean it with a pressure washer!!
Yours is a difficult issue without having to pay alot of money, the one's for sale on ebay could have a history of condensation etc.
Also there are small rubber washers you need to replace on the mounting bolts everytime the lights are removed/installed.
These Astons do have their issues and your not the only one to be frustrated with ongoing issues, my DB9 has had a fuelling/vacuum issue for the last 18 months and been in and out of AM specialist garages with no success, I have also worked on it myself and it's still ongoing. My power steering pump burn't out after I flushed out the PS fluid using the AM procedure and the Aston 1936 video, I was massively unlucky because although I didn't know it at the time there was trapped air in the system so when I started the car up the pump burnt out. I removed the pump and it's now getting reconditioned as a new one from AM is £1100!!!
Try not to get too down heartened with her, the way I view it is we are very lucky to own these cars!!
Good luck
paulrog1 said:
Try not to get too down heartened with her, the way I view it is we are very lucky to own these cars!!
Good luck
Thanks very much. Yes, with all my other cars, if they had a problem I just paid a bloke to fix them. With this one, or perhaps all Astons, you pay not to get them fixed - notably the so-called specialist who handed me a 4-figure bill and say 'Let's try new spark plugs, maybe that will work'.Good luck
A prima donna for sure. But you can still pull up outside a chip shop and someone will say 'Is that your Aston?', or park in a field full of expensive cars at a Young Farmers wedding and you still win
Ahhh, so sorry your ownership experience is being plagued by this. It’s a real shame, as most of us have been able to sort them out in the end often for little cash. When I bought my car the rears had an inch of water in them and things growing, loads of germinating seed pods swollen to the size of peppercorns.
Mine were flickering, dead LED units with one light not coming on at all. Some s/h units, loads of TLC, dismantling, cleaning, drying, hole drilling and resealing and eventually all came good.
Don’t give up hope, eventually you will hit on the solution, and laugh about it one day…..
Mine were flickering, dead LED units with one light not coming on at all. Some s/h units, loads of TLC, dismantling, cleaning, drying, hole drilling and resealing and eventually all came good.
Don’t give up hope, eventually you will hit on the solution, and laugh about it one day…..
Edited by Calinours on Thursday 6th April 15:04
Simpo Two said:
That's my thought too, unless LEDs can glow twice as brightly as intended.
It's not so much the brightness as the pattern of illuminated LEDs. The sidelight is the horizontal bar and the brake light is the "boomerang" above and around it.Simpo Two said:
Can a faulty earth make a brake light come on when the brake isn't applied?
Yes it can. You often see older cars where something like an indicator glows when the brakes are applied. If the current can't flow to earth but is finding its way via another bulb it can illuminate any other bulb in the cluster, but with conventional filament bulbs they usually don't glow at full brightness.Simpo Two said:
And if an earth fault is not in the unit but elsewhere in the car, wouldn't it affect both lights?
Not necessarily, because each lamp will often have its own local earth as the lamp body, being plastic, doesn't conduct electricity. There will be a black wire from the loom somewhere close to the lamp cluster that will be attached to an earth stud on the aluminium body. It does depend on how AML designed the earth points and wiring in the loomSimpo Two said:
I've tried everything to make this problem go away, from a replacement unit by the dealer, to getting a mechanic to look at it, to a repair, and the ***ing thing keeps coming back to haunt me.
You need to establish the root cause - simply swapping out parts like lamps won't do it, especially if it's a loom fault. You need either an auto electrician or someone familiar with auto electrics who's handy with a test meter. I doubt that the root cause would show up on AMDS, either. Best of luck, and maybe try the lamp swap? As far as will they temporarily go into the opposite hole, then no, but you can either leave it in the boot (if the wires will reach) or hang it from a bit of bent wire, like a cut coat-hanger, so it' s not hanging off the loom - that's not a good idea. If you do remove them yourself be careful when you refit, as over-tightening the fixing can crack the lamp - then you're in a different world of pain.
Edited by LTP on Wednesday 5th April 18:52
Thanks very much for the info; if you're ever in the area there's a free lunch with unlimited beer waiting 
I might try the unit swap trick when the weather is better, but not feeling the excited about it and might damage the good one. Probably a job for a good autoelectrician to find it once and for all, and luckily I know one.
I might try the unit swap trick when the weather is better, but not feeling the excited about it and might damage the good one. Probably a job for a good autoelectrician to find it once and for all, and luckily I know one.
Simpo Two said:
Thanks very much for the info; if you're ever in the area there's a free lunch with unlimited beer waiting
I might try the unit swap trick when the weather is better, but not feeling the excited about it and might damage the good one. Probably a job for a good autoelectrician to find it once and for all, and luckily I know one.
If I was in the area I'd be suggesting I take a run out with my multimeter in the boot - I'm not an auto sparkie but I've fixed a few non-Aston cars of my own over the years. I might try the unit swap trick when the weather is better, but not feeling the excited about it and might damage the good one. Probably a job for a good autoelectrician to find it once and for all, and luckily I know one.
What I don't know is how much of the boot trim you need to pull out to get to the back of the lamps, how difficult is is and long it would take. If you can get the trim out and know a good autoelectrician, then ply him/her with beer.
sexual stereotyping fixed.
Edited by LTP on Thursday 6th April 15:21
LTP said:
What I don't know is how much of the boot trim you need to pull out to get to the back of the lamps, how difficult is is and long it would take.
The proper way to do it is to loosen the ally rail along the boot opening, pull the rubber edge trim off, winkle the carpet trim out from beneath, prise it forward a bit, disconnect the light then complete the removal. So not difficult in the scheme of things, just a faff. When the mechanic was adjusting the unit last time he left the trim under the boot strip, left the light connected and just got his arm round.It's a funny thing, I'm very good at DIY and quite inventive, but have no confidence working with cars. The risk of hitting an unforeseen barrier or snapping something important just seems to great. Here, even if I managed to swap the units over the fault probably wouldn't show itself (I can't drive it with the lights missing), and then I'd have to get them back again as they were. So high risk, time and effort for low return.
Simpo Two said:
It's a funny thing, I'm very good at DIY and quite inventive, but have no confidence working with cars. The risk of hitting an unforeseen barrier or snapping something important just seems to great. Here, even if I managed to swap the units over the fault probably wouldn't show itself (I can't drive it with the lights missing), and then I'd have to get them back again as they were. So high risk, time and effort for low return.
You don't need to drive the car. You just need two people (one in the car to operate the switches and/or press the pedals, one at the back to note what's happening). You may have to have the ignition in "Pos 2" or engine started to be able to test fog lights, but AFAIK the brake lights on an Aston will come on if you just press the brake pedal. Similarly, the sidelights will illuminate from the light switch. You could do the light swap in a garage (with the door open if you need to idle the engine)edited to add
Stating the obvious, but If you are going to idle the engine, do it in "Park" or "Neutral" (preferably Park if available) not in "Drive" or "Reverse"
Edited by LTP on Thursday 6th April 16:43
Took a two mile trip to the supermarket today to restock with beer etc.
Today the brake light has magically repaired itself, but the indicator light has broken. Well, I hear a double speed tick and the display says 'Bulb failure left turn indicator'. Naturally all three lights on that side are working. I am exactly back to the message two months ago which prompted me to take it to the garage to get the allegedly-broken bulb replaced, to be told that the tail unit was borked, to get the tail unit allegedly-repaired.
The fault, whatever/wherever it is, comes and goes and the messages vary from day to day.
Today the brake light has magically repaired itself, but the indicator light has broken. Well, I hear a double speed tick and the display says 'Bulb failure left turn indicator'. Naturally all three lights on that side are working. I am exactly back to the message two months ago which prompted me to take it to the garage to get the allegedly-broken bulb replaced, to be told that the tail unit was borked, to get the tail unit allegedly-repaired.
The fault, whatever/wherever it is, comes and goes and the messages vary from day to day.
You definitely need a man with a meter to work out if the faulty signals are being supplied to the lamp unit, or whether the car is supplying the correct input into the lamp but things are getting confused within the lamp itself. But I'm beginning to suspect that the issue might be the car rather than the lamp unit. It might be worth removing the boot trim, see if you can spot the earth stud for that lamp, remove the eyelet, clean it, clean the stud and the body where contact is made, reassemble and re-tighten the nut
When you say you got the double-speed click (which is usually an indication of a bulb failure) did all of the indicator bulbs illuminate and flash correctly? And when you say "all three lights on that side are working" do you mean the three lights in the LH rear lamp unit (brake, indicator and side) or did you mean all three LH indicators (front, rear and side repeater in the mirror).
Also want to say you have my sympathy, and not wanting to depress you further but intermittent electrical problems can be an absolute bd to track down and fix. I also appreciate how frustrating it can be having an invisible idiot behind a keyboard typing things like "why don't you try....?". So I won't suggest anything else other than stock up on beer for your tame auto-electrician.
When you say you got the double-speed click (which is usually an indication of a bulb failure) did all of the indicator bulbs illuminate and flash correctly? And when you say "all three lights on that side are working" do you mean the three lights in the LH rear lamp unit (brake, indicator and side) or did you mean all three LH indicators (front, rear and side repeater in the mirror).
Also want to say you have my sympathy, and not wanting to depress you further but intermittent electrical problems can be an absolute b
d to track down and fix. I also appreciate how frustrating it can be having an invisible idiot behind a keyboard typing things like "why don't you try....?". So I won't suggest anything else other than stock up on beer for your tame auto-electrician.^^ Continuing thoughts appreciated
LTP said:
It might be worth removing the boot trim, see if you can spot the earth stud for that lamp, remove the eyelet, clean it, clean the stud and the body where contact is made, reassemble and re-tighten the nut
Can do - but does the tail light have an earth stud anywhere nearby?LTP said:
When you say you got the double-speed click (which is usually an indication of a bulb failure) did all of the indicator bulbs illuminate and flash correctly? And when you say "all three lights on that side are working" do you mean the three lights in the LH rear lamp unit (brake, indicator and side) or did you mean all three LH indicators (front, rear and side repeater in the mirror).
The orange indicator section seemed to be illuminated as brightly as the other side, just flashing twice as fast. Front indicator and side repeater all working. No repeaters in the door mirrors.LTP said:
Also want to say you have my sympathy, and not wanting to depress you further but intermittent electrical problems can be an absolute bd to track down and fix. I also appreciate how frustrating it can be having an invisible idiot behind a keyboard typing things like "why don't you try....?". So I won't suggest anything else other than stock up on beer for your tame auto-electrician.
He requires more than beer unfortunately, but he's the guy who found that (what everybody else said was) a misfire was a knackered torque converter. A brace of W12 Bentleys outside his premises suggested he has adequate skills - and more software than you can shake a stick at, say people who know him!d to track down and fix. I also appreciate how frustrating it can be having an invisible idiot behind a keyboard typing things like "why don't you try....?". So I won't suggest anything else other than stock up on beer for your tame auto-electrician.Edited by Simpo Two on Friday 7th April 19:40
Simpo Two said:
Can do - but does the tail light have an earth stud anywhere nearby?
To be honest, I don’t know. But my guess would be “yes”.Simpo Two said:
Just checked again - indicators working normally now, no messages.
But if I put the sidelights on then press the brake pedal I get a brake light message and double-bright light on left as per photo at top, as if the brake light is jammed on.
Sorry if I’m appearing dim (pun unintended, but, I’ll take it) but the picture at the top shows, to my eyes, both sidelights on and the LH brake light on. So if that’s what you’re seeing with the sidelights on and brake pedal depressed, that would indicate to me that the LH lamp is doing what was expected, but the brake light on the RH side is not working.But if I put the sidelights on then press the brake pedal I get a brake light message and double-bright light on left as per photo at top, as if the brake light is jammed on.
I’m taking my Vantage out tomorrow (basically same lamps) so, if I remember, I’ll get my wife to sit and operate the controls while I check exactly which elements of the lamps illuminate when various things are activated.
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