Nooo headlight weirdness!

[big_treacle]

Morning. Interesting drive home from work last night when my headlights went mad.
I have sidelights & full beam but not normal dipped headlights. I unplugged & replugged the light control boxes to no avail. I've just been looking at them (labelled 'lights switching unit' & 'indicator & hazard lamps switching unit') - I can't see any burn marks to indicate problems. I guess the relays themselves might be knackered. Switching the lights on and off I did notice the dipped beams briefly flashed on once.
Any ideas what I should look at next?
Cheers

[Steve_T]

big_treacle said:

Morning. Interesting drive home from work last night when my headlights went mad.
I have sidelights & full beam but not normal dipped headlights. I unplugged & replugged the light control boxes to no avail. I've just been looking at them (labelled 'lights switching unit' & 'indicator & hazard lamps switching unit') - I can't see any burn marks to indicate problems. I guess the relays themselves might be knackered. Switching the lights on and off I did notice the dipped beams briefly flashed on once.
Any ideas what I should look at next?
Cheers

Perhaps there's a dry joint on one of the circuit boards?

[big_treacle]

Steve_T said:

Perhaps there's a dry joint on one of the circuit boards?

Yeah maybe. I'll see if I can see anything. I'm gonna get an electronics mate of mine to check it out tomorrow to see if he can find anything.
Just wondered if there are any other obvious things to check?

[methodwares]

that's what happened to mine. the control box in the boot has 6 relays and one of them no longer makes a clicky noise when power is applied. I couldn't find that specific relay anywhere. I could find some with the same spec, but they all had different pin layouts.

If it is the relay and you can get one, can you get me some so I can fix my old box.


Oh, I got a new one from one of the TVR parts places on the web.

[big_treacle]

methodwares said:

that's what happened to mine. the control box in the boot has 6 relays and one of them no longer makes a clicky noise when power is applied. I couldn't find that specific relay anywhere. I could find some with the same spec, but they all had different pin layouts.

If it is the relay and you can get one, can you get me some so I can fix my old box.


Oh, I got a new one from one of the TVR parts places on the web.

Ah yeah that does sound a bit similar. Can't really hear any relay click when I switch it.
Just checked all the fuses & look OK. I'll get my electronics bloke to have a look tomorrow & go from there.
Cheers

[methodwares]

you can pull the box out and open it. a 9v battery is just about the right size to hit the switching voltage pins and enough juice to actually make them switch, so its an easy test. there is a row of 4 and a row of 2 on the PCB and i think it was one of the middle ones on the row of 4 that conked on mine

[jonnie5]

You may have already checked this, but have quick check of all of your fuses as well.

I once had a similar thing when the entire lighting system went completely , and it took a very confused AA man about 2 hours to finally discover one blown fuse.

[brakedust300]

Very sorry to drag this one out again but i now have this exact problem.... what was the cause in the end? Can the relay be replaced or do i need a new light control box?

[kojak]

I had this. Side lights and full beam worked, but dipped didnt. It was the control box in the boot in my case. If you havent already checked the unit, do so first. Check that 2 of the wires arent burnt out.

Edited by kojak on Monday 28th July 21:24

[central]

kojak said:

I had this. Side lights and full beam worked, but dipped didnt. It was the control box in the boot in my case. If you havent already checked the unit, do so first. Check that 2 of the wires arent burnt out.

Edited by kojak on Monday 28th July 21:24

Same thing happened to mine a few weeks back.

The box turned out to be OK, just a couple of wires slightly frazzled. (caused by a *tad* of play in the connector)

[brakedust300]

Just checked the box & cables & all seems ok, I get the strange "flash" of headlights as I power down, did anyone change a relay & fix it?

[DonnyMac]

brakedust300 said:

Just checked the box & cables & all seems ok, I get the strange "flash" of headlights as I power down, did anyone change a relay & fix it?

I had this rapid flashing (not the control box/wiring) I 'fixed' mine by playing with the wires behind the headlight/heater/aircon dials.

Fixed after a couple of plays with it.

[big_treacle]

Mine turned out to be the control box

[methodwares]

brakedust300 said:

Just checked the box & cables & all seems ok, I get the strange "flash" of headlights as I power down, did anyone change a relay & fix it?

big_treacle said:

Mine turned out to be the control box

Mine was the control box as well, a relay inside the control box (not on the fuse panel). I was able to determine the faulty one, but had no luck finding the replacement. none of the ones I found had the correct pin-out to solder onto the board. if you open the control box and use a 9V battery, you can trigger the relays (6 of them) one at a time to determine if one is faulty.... if like mine, one won't 'click'

[brogenville]

I had a similar problem where the full beam wouldnt go on. After a bit of head scratching I managed to trace it back to a duff relay in the control box. Luckily my local tv repair man was able to provide me with a relay that dropped straight in.

Naturally I was pretty chuffed with myself to fix the problem for about 2 quid when the breakers wanted nearer 100 for a used replacement box.

[QuiteQuietCerb]

controlo box here too. 2 cables burned out, had to be bypassed

[jonbarrett]

I wonder if the time has come to reverse engineer some of these control boxes and start manufacturing some new ones. I know some electronics distributors that specialise in sourcing obsolete components. Assuming the PCBs are single or double sided they should be simple to redesign. The problem will come if any of the silicon is bespoke programmed. Hopefully all the logis is off-the-shelf.

I'm willing to give one a go but I'd need someone to send me a duff box. Anyone interested?

[kojak]

Mine was a bad relay in the box also.

[methodwares]

don't think there is any logic in this particular box. just relays, resistors, diodes, etc.

i'll have to try my local tv repair guy see if can get a new relay, then i'll have a good as new box for next time.

[brakedust300]

Any ideas where they get the relays from? Surely cant be a custom TVR part? they must be used in something else?
Ill pull mine apart tonight....