Headlight switch and loom fires.....DIY prevention

[Moreland 10]

Wish I'd seen this post before today, same problem of burnt out brown wire. I've tried to check the damage and only seems to be the light switch loom so was glad to find out it's only a short one instead of having the whole dash out. I've sourced a new loom and will be doing this mod when it arrives! I've got another problem though that now my ABS light is on, heater fan and window wipers don't work either. All fuses seem ok, could this be a relay problem? Any suggestion out there? Thanks

[dingo 0]

good thinking here, really easy to do! thanks

[Rob_ 10]

I've just picked up a Corrado this week. I noticed yesterday that the headlight switch was warm/hot to touch so im guessing this is why. Thankyou for this post. My last car, a Mini Cooper Sport (old school but cool), fell victim to an electrical short behind the dash resulting in not only a scary drive to work but also a complete write-off. Now i know what im upto tomorrow! Maplins here we come!

 

---------- Post added at 02:54 PM ---------- Previous post was at 02:48 PM ----------

 

My ABS light has also come on. Started intermittently but now seems a more permenant feature. Is this related?

[RW1 0]

These will be useful as they don't have the little filament bulb inside that is on all the time causing the heat. Use LED's and run cold.

http://the-corrado.net/showthread.php?56755-What-would-the-interest-be-in-new-late-headlight-switches-Pricing-Update.

 

ABS, nope..... looking at probably a wheel sensor. Given the rain, check and WD40 the front left ABS connection just by the bottom of the strut behind the disc splash plate. Also, may as well do the right side while the tools are out.

 

If not that..... you need a diagnostics session with VCDS and see what fault code(s) is being shown.

 

.

[Rob_ 10]

Going back to the light swtich issue... is the reason the wires tend to short because of the heat given off by the two bulbs inside the switch itself? Or is it the amount of voltage passing through that one particular brown wire, in which case would it not be better to locate the fuse closer to the other end of the cable rather than right next to the switch? Over the weekend I took the switch apart and replaced the two bulbs with 12V LEDs. It was a fiddley job but as a result the switch no longer gets hot, but should i still worry about this short circuiting issue?

[RW1 0]

Going back to the light swtich issue... is the reason the wires tend to short because of the heat given off by the two bulbs inside the switch itself?

 

Short occurs cos the bulbs make the switch cap plastic levers inside go brittle and break. If one breaks (the upper most one), the other plastic lever then skews the switch internal contact slider and its possible to put 12 volts directly onto the brown (earth) wire and so melt the wire insulation and heat it up.

 

Or in case of the German made original swtiches, they can come new with poor soldering which has bridged the 12 volts onto the brown wire and same as above happens. Switches have been like this since as far back as 1997 and I know of three incidents on fitting a replacement toasting the wire including mine.

 

Or is it the amount of voltage passing through that one particular brown wire, in which case would it not be better to locate the fuse closer to the other end of the cable rather than right next to the switch?

 

Brown wire is an earth wire used only to complete the small bulb (centre lamp symbol) illumination circuit. Therefore it is only a smaller size wire and heats up fast when the fault occurs. The brown wire has no part to play in the sidelight or headlight circuits.

 

I located mine at the fuse/relay plate as per the post early in the topic. Mainly for ease of access by the bonnet pull handle.

 

I did some test with 1 amp car fuses and same size wire and length with a car battery. It doesn't matter which end really as the results with the fuse still protected the brown wire under test with no damage. The fuses always went instantly. Reducing the fuse to less with a cartridge fuse ampage rating on a 1.2watt bulb ciruit for the direct short that occurs can only be beneficial. Looking at the switch mechanical contacting inside, the short is capable of carrying headlight currents easily and more, hence the fire risk. Reason the other wires in the loom do not burn quickly is because they are of a heavier gauge. In my incident they did show signs of heat not directly attributable to the adjacent brown earth wire. I managed to get the faulty new switch off PDQ.

 

Over the weekend I took the switch apart and replaced the two bulbs with 12V LEDs. It was a fiddley job but as a result the switch no longer gets hot, but should i still worry about this short circuiting issue?

 

The shorting issue will still be there. You may have fitted the LEDs but as the switch could still fail as the bulbs will have already made the plastic somewhat brittle. Plus if you are one of those peeps who punches switches ON/OFF, then the top internal lever could still break, even if not affected - the levers are not strong. Then a skewed contact plate will bridge the 12 volts to the brown wire and ......

 

It is a good worthwhile dormant cheap mod until one day ............

 

.

Edited August 15, 2011 by RW1

[Big_Al 10]

Just a quick question, can new switches be bought from anywhere ?

 

I am already getting the relevent parts to put the inline fuse on the wire, but just thought I might as well replace the switch too.

[8vMatt 1]

Just a quick question, can new switches be bought from anywhere ?

 

I am already getting the relevent parts to put the inline fuse on the wire, but just thought I might as well replace the switch too.

 

Hi mate,

 

Give me a shout if you do want a new switch to go with putting a fuse in the line. And, no the switches aren't available in shops or online as I've brought them into the country direct from the manufacturer.

 

HTH, cheers Matt.

[Corradoholic 10]

Hi guys,

 

just had a look behind the dreaded headlight switch...hoping for the best....but finding the worst.

it seems that the brown wire has completely burned the casing from the wire as far as i can see leaving just the bare wire. i take it that this is a bit of an issue.

There is some minimal damage to the other wiring that i can see but i dont know how far down the wire is melted or what other issues there may be.....but there are no non working electrics as far as im aware.

can someone please advise me on which items i should replace - should i do the headlight loom upgrade, new switch and in-line fuse modification? are all necessary and is anything else required?

 

Many thanks,

 

Max (not looking forward to driving his car for a few days)

[GusPW 0]

Hi guys,

 

just had a look behind the dreaded headlight switch...hoping for the best....but finding the worst.

it seems that the brown wire has completely burned the casing from the wire as far as i can see leaving just the bare wire. i take it that this is a bit of an issue.

There is some minimal damage to the other wiring that i can see but i dont know how far down the wire is melted or what other issues there may be.....but there are no non working electrics as far as im aware.

can someone please advise me on which items i should replace - should i do the headlight loom upgrade, new switch and in-line fuse modification? are all necessary and is anything else required?

 

Many thanks,

 

Max (not looking forward to driving his car for a few days)

 

You'll probably find that the wires are damaged all the way down to the fuse box, mine was even though it didn't look to bad before I removed it. Find an undamaged switch to fuse box loom from a breakers and buy a new switch of 8vmatt.

And fit the in line fuse

Edited August 14, 2012 by GusPW

[8vMatt 1]

Thanks for the recommendation Gus.

[Corradoholic 10]

thanks GusPW - does it have to be a breakers or is it part of the headlight loom upgrade available on here? or do you know of anyone on here that makes a switch to fuse box loom (if it is a separate to the headlight one)?

 

Matt - i'll get in touch through the other thread for a switch, cheers.

[GusPW 0]

No problem, don't know much about loom upgrade i'm afraid, never bothered myself, found headlight intensity adequate with osram night breaker bulbs. Others i'm sure would disagree.

expect some one with more knowledge of relay looms will be along to answer that.

 

8vmatt- no problem, well chuffed with mine.

[smithy21 10]

I reckon I'll give it a go as well. Look out for the headlines. "Car bursts into flames in driveway" which is slightly better that "Car bursts into flame on motorway" This electricity stuff is puzzling, don't trust anything I can't see.

 

 

 

hi all, need some help please, i beleive this fault as already happened, will putting in this in line fuse bring back my light on the dip beam switch. it lights up on the side lights but when switched to dip beam the green light on the switch goes out but the dip beam works. would disconnecting the resistor for the dim dip headlights help. (mines a 1993 2.0L 16v and dont accualy know if one is fitted) when you turn on the side lights it takes a while to light up, as if someone is working a dimmer switch lol. also, when you take a test light to the wires at the back of the head lamp switch, on dip beam all the wires are live! some lights it up brighter than other wires :/

are the dip beam lights ment to be on the same time as the full beam lights. i thought they were ment to be individual. could this be a relay causing this? and what relay is the full beam and dip beam?? someone please help???

[Portent 0]

hi all, need some help please, i beleive this fault as already happened, will putting in this in line fuse bring back my light on the dip beam switch. it lights up on the side lights but when switched to dip beam the green light on the switch goes out but the dip beam works. would disconnecting the resistor for the dim dip headlights help. (mines a 1993 2.0L 16v and dont accualy know if one is fitted) when you turn on the side lights it takes a while to light up, as if someone is working a dimmer switch lol. also, when you take a test light to the wires at the back of the head lamp switch, on dip beam all the wires are live! some lights it up brighter than other wires :/

are the dip beam lights ment to be on the same time as the full beam lights. i thought they were ment to be individual. could this be a relay causing this? and what relay is the full beam and dip beam?? someone please help???

 

Do you mean dipped lights or side lights? The green light on the headlight switch should work as follows...

 

Switch off - green light off

Switch to side light position - green light on

Switch to main beam position - green light off again (regardless whether dipped or full)

 

I can't comment on which wires should be live but the lights taking a while to get brighter isn't right and I would suspect a badd connection or faulty wire somewhere. Check the connections and wiring behind the switch and also around the headlights themselves.

 

Is the car fitted with an uprated headlight wiring loom? Cheap ones can be problematic. Alternatively if one isn't installed then consider kurzys uprated loom which should bypass a faulty connection and dramatically improve the brightness.

 

I'm pretty sure that dipped and full beam come on together.

Edited August 17, 2013 by Portent

[bully 10]

Today bully caught fire due to this i managed to burn my hand putting out the fire im now left stranded and need to fix the car

 

Started with main beam lights not working

 

Whilst trying to fix this in the workshop i saw smoke coming from the switch i pulled it out and it it was on fire

[lilfuzzer 1]

Wow good job u were there hope it hasn't done too much damage bud

[bully 10]

really looking for some help on this... if anyone has the parts.. can get the parts... as im now in the bus.. Please Help :(

 

car is located near high wycombe, even if anyone knows someone close by can give me some help fixing this also.. as i think its a bit beyond my skills... any help or advice welcomed.

[ryan_welshman 10]

Anyone have trouble where one sidelight will stay on after ignition is switched off? Goes off after ignition is switched on an then switch is flicked a few times but juat annoying to check everytime to make sure the battery isnt run flat!

[seanl82 23]

Check you've not left your indicator on. It's supposed to do that. :wink:

[delfinis38 1]

Check you've not left your indicator on. It's supposed to do that. :wink:

 

parking light :)

[ryan_welshman 10]

Ahh ok, that makes sense. Cheers

[Peteb 10]

Hi, thought I would put an inline fuse in today but noticed someone had already put one in, but it's on the grey and blue wire. Is this any good? cheers.

[Hairyarse 10]

That looks like just a spade connector to me?

[Pete b 10]

Yeah it's connected to an inline fuse but not sure what this wire is so think I will just do the earth any way to be safe. Both the earth and the live are the same gauge wire so not sure why this happens.