Check Rear Lights - Amber Warning
Discussion
This has been flashing up for a couple of months now.
It only happens when I have started the car and press the brake pedal to move out of Park.
I have had a couple of people check my rear lights for me and they are always fine.
Is this something I can just ignore?
This is on an XJ8 (X308).
It only happens when I have started the car and press the brake pedal to move out of Park.
I have had a couple of people check my rear lights for me and they are always fine.
Is this something I can just ignore?
This is on an XJ8 (X308).
There are two microswiches in the brake light switch assembly - possibily one has got out of sync with the other due to wear or dirt and this can cause fault random messages.
If you have cruise control do fault indications only happen when it's swiched on? That'll almost certianly be the cause if so. The switch is a monumental PITA to get out so a shot of WD 40 in situ might do the trick be all you need.
If you have cruise control do fault indications only happen when it's swiched on? That'll almost certianly be the cause if so. The switch is a monumental PITA to get out so a shot of WD 40 in situ might do the trick be all you need.
This from my recent XK8 experience however I am led to believe by my local indie of 3+ decades experience that the XJ8 series uses the same design (although a little mechanically different in the pedal actuation). Certainly if fitted with cruise control (and possibly without it) there are two micro-switches fitted to the brake switch circuit board. The current view is that one indicates that the brake pedal has been depressed and the other turns the cruise control off. Additionally it seems certain that the two switches act in a fail-safe mode in that one is normally closed and one normally open and if at any time both are in the same state for more than a very short duration (e.g. > 100mS) a warning is displayed as posted and if fitted cruise control is disabled.
Mine has been playing up since last August and I kept putting it off having read the horror stories about replacement but finally got round to it last weekend. I can confirm that it does not matter if cruise is turned on or off, it still triggers randomly and from my investigations it would also seem that as many if not more of the faults are due to a solder joint going bad (mine was) as are due to a faulty micro-switch (these are very hardy sealed items with normally a very low failure rate). As such, you might as well spray air-freshener on it as WD-40 (your car will smell nicer as well).
The micro-switches can be replaced, joints can be re-soldered (there are tracks on both upper and lower sides of the PCB but it is not multi-layer) so if you are handy with a soldering iron a low-cost repair can be effected. I bought a replacement from a breakers, checked the micro-switches with a multi-meter (not always effective if a faulty item is intermittent but I decided to risk it) and de/re-soldered them to the board as a preventative measure.
I can't speak of the XJ specifically but on the XK8 removal is not too bad at all although replacement can be very awkward and time-consuming and is much eased by having a second person with supple wrists and small hands manoeuvre the switch back into position while you watch the holes to see when the bolt threads appear. Tip: mark the end of the upper bolt with a spot of white paint or tippex before removal. That way when you can only see one bolt through a hole you will know if it is the right one for the right hole. You will also be able to orient it properly when trying to replace. Do get a good extension (9"-12") for an 8mm socket. There is a built-in auto-adjustment ratchet in the switch - make sure it is reset before re-fitting or you might be unlucky and have to do it over (although I have heard it can be reset without removal with a screwdriver).
All in all it took about 15 minutes to remove, about 55 minutes to replace (which latter was a 40-minute struggle with a lot of cursing, a 5 minute break and change around then suddenly in about 10 minutes it was in). At least we didn't have to resort to seat removal, tricks with fishing line or piano wire and nobody got a bent spine
After a week or more with no messages (they were appearing almost daily), all is well now.
Jim
Mine has been playing up since last August and I kept putting it off having read the horror stories about replacement but finally got round to it last weekend. I can confirm that it does not matter if cruise is turned on or off, it still triggers randomly and from my investigations it would also seem that as many if not more of the faults are due to a solder joint going bad (mine was) as are due to a faulty micro-switch (these are very hardy sealed items with normally a very low failure rate). As such, you might as well spray air-freshener on it as WD-40 (your car will smell nicer as well).
The micro-switches can be replaced, joints can be re-soldered (there are tracks on both upper and lower sides of the PCB but it is not multi-layer) so if you are handy with a soldering iron a low-cost repair can be effected. I bought a replacement from a breakers, checked the micro-switches with a multi-meter (not always effective if a faulty item is intermittent but I decided to risk it) and de/re-soldered them to the board as a preventative measure.
I can't speak of the XJ specifically but on the XK8 removal is not too bad at all although replacement can be very awkward and time-consuming and is much eased by having a second person with supple wrists and small hands manoeuvre the switch back into position while you watch the holes to see when the bolt threads appear. Tip: mark the end of the upper bolt with a spot of white paint or tippex before removal. That way when you can only see one bolt through a hole you will know if it is the right one for the right hole. You will also be able to orient it properly when trying to replace. Do get a good extension (9"-12") for an 8mm socket. There is a built-in auto-adjustment ratchet in the switch - make sure it is reset before re-fitting or you might be unlucky and have to do it over (although I have heard it can be reset without removal with a screwdriver).
All in all it took about 15 minutes to remove, about 55 minutes to replace (which latter was a 40-minute struggle with a lot of cursing, a 5 minute break and change around then suddenly in about 10 minutes it was in). At least we didn't have to resort to seat removal, tricks with fishing line or piano wire and nobody got a bent spine
After a week or more with no messages (they were appearing almost daily), all is well now.
Jim
Edited by jimattfield on Sunday 12th May 20:07
I should have clarified WD40 in situ may not be a cure but it can be a useful diagnostic tool if it gives you a tempoary - or maybe - permanenet fix. It's such a pain to access the switch IMO you're going to actually remove the original one then for peace of mind it's probrably best to replace it with a new one.
About £40 from British Car Parts when I looked for one.
About £40 from British Car Parts when I looked for one.
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