Headlight switch relay mod and still a dead headlight switch?
 

I probably shouldn't start a thread yet since I am a professional with automotive electricals but... any advice between this afternoon and tommorow could help out and makes things faster.

What's going on.

I did the headlight switch mod over a year ago but my interior lighting started to flicker and give out sometimes. About 4 months ago, my fog lights popped the fuse for them and havent really been hard pressed on finding out why. A few days later, my dash lighting started to flicker again and finally died and I could smell the dreaded "something just got hot" smell but no smoke or anything. Fast forward to yesterday I realize my parking lights no longer work... but they work when I trigger why remote start and alarm, but if I crank the switch it is zero, nada. I listened for the relay and I couldn't hear squat.

What really confuses me here is that I did the relay mod and the relay should only be drawing 150mA of current so that is nothing to the switch, but for some reason I think it may be the switch. I need to pop the binnacle and see what the plug looks like. The smell I could smell didnt smell like a cooked wire but more like overheated plastic.

So basically I am going to pull the binnacle tommorow and survey the headlight switch connector, and if I have to for the time being, just install a toggle switch until I can afford a properly rebuilt or new headlight switch if it comes to that.

Any other suggestions on where to look?

i'll bet you find problems with the relay and the high(er) current carrying wires, rather than the low current side of the system.

Or maybe else something entirely!

Most likely.

This is what I know as of now before taking anything apart. The relay is not being activated as there is no clicky clicky on the headlight harness. The fog light relay however is working but has no power because the fuse blows when it rains and I flick the lights on.

Consider doing some tests with your alarm disconnected and completely off the system. Our cars have a hard time tolerating extra load.

It only draws 8-10ma of standby current armed...doubt it has anything to do with my parking lights since it is connected in front of the relay and can flash the lights just fine.

If anyone is curious, I placed the parking light wire for the alarm/RS in front of the relay (toward the car) so that it wont flash the interior lighting (saves wear and tear on bulbs)

Anywho, I aint doing shit today as it is below freezing. Jack, you enjoying the weather on the other side of town buddy?

Yup, I'm staying warm today too. I just picked up some pretty nice original 'Vert seats from JKruger. They are going in my 10th Anny after a quick redye treatment. The heater in the truck kept me nice and warm.:icon_tup:

Love me some headrest speakers!

I dont think I'll have to work tomorrow so hopefully I can get something done. My wife works nights at the Dallas PD (yes she deals with CRAZY shit) and sleeps during the day, so I am usually taking care of my daughter unless I am working. Tomorrow she is off so hopefully I can take advantage of my parents garage and dive into this. My main priority is going to get after the parking lights because...well...they are a necessity. I can live without fog lights for the time being now. I'll just have to pop by work and get some of my tools and my multimeter.

I plan (plan) to take a lot of pictures for posterity, but you know how that goes when you are in the zone.

Fixed it today!

I took the switch out and popped the cover and the problem was very visible. The headlight switch problem is an engineering flaw of epic fail proportions. I took pics of the fix and will post a how-to either later today or tomorrow morning.

When you guys see the pic and my explanation of why headlight switches fail, the engineering flaw will be totally obvious.

I have my parking lights and interior illumination now. :nod:

I've fixed 3 so far that have all failed the same way. The trace on the PCB can't handle the current. Bypass that with a wire from the actual switch to the plug and you're good to go. No splicing or relays required.

Correct. Eeverywhere else on the board has large traces for that circuit except for that one spot.

I posted a thread on fixing it, although I did it differently because my dumb ass forgot to grab my multimeter from work and couldn't check continuity. If I hadn't forgot that, I would have done it the way you described.

The fun part is they sometimes continuity test just fine. It's only once you try to pull a dozen amps through it that it flakes out. The first time this happened on mine it had me scratching my head for a while. I even took the switch apart and pulled the board out of the switch housing (not recommended) to make sure I wasn't missing some failed passive component somewhere. Sort of acts like a bad solder joint even when all the solder joints have been re-done.

Mine failed on the little tiny and thin trace that bridges the 12v input pin and the through hole connection that connects that trace to the other side of the board.

I pulled the board out (I dont recommend it either!) and the entire circuit for the W/G wires 12v input, the traces are huge. It's just that one spot where it is too thin and likes to get toasty.

Thankfully, you dont need to remove the board to get to it as you can expose it by just removing the white plastic vented cover. I took the whole thing apart just to make sure there wasn't any more debauchery going on. If you do remove the whole board...expect lots of cussing.

Lol sounds like the wiper switch - can't get the board out without de-soldering a ton.

Yeah, and I was pretty sloshed when I did it which made it worse.

Want to mess with the headlight switch? Put the beer down!

I did manage to get the binnacle off without removing the steering wheel though, which was rather scary as it requires finesse and the bending of plastic. :scared:

Do either of you have a pictures of a switch after doing IceMark's relay mod? Do the new relays fit inside the switch or are they external?

I'm about to do mine, as the switch has the burnt plug syndrome Lol

U talking the headlight or wiper switch mod? The headlight mod is an external relay, but I've never seen pics. The wiper repair replaces relays inside it with same sized better ones with same pin arrangement.

Headlight mod

What relay are y'all using to do the mod on the headlight switch? I've tried to search for the relay based on the information Icemark gave, but I cant for the life of me find a STDM (Single Throw, Dual Make) relay.

Would this one work?

4 Lot Temco 12 V 30 40 Amp Bosch Style s Relay with Harness Socket Automotive | eBay

That'll work.

So did you get it working or not?

Haven't ordered yet. My car is a LONG way from being done. Just doing research little by little.

I'd still like to see a completed repair and where yall placed the relay.

I just wired it into the headlight harness using scrap wire from work of the same gauge as OEM. I left 4 inches of slack between the relay and where I patched into the headlight harness and just zip tide the relay to the headlight harness.

The easiest way to get to the headlight harness is to remove the knee bolster from below the steering wheel, pull the binnacle (instrument cluster surround) and unplug the headlight harness. Once unplugged, pull it down from under where the knee bolster would normally reside and you got a couple of feet worth of slack in the headlight harness to work with. When done, fish it back up the dash (which is easy).

I do remote starts at work all the time so the scrap wire I used was scrap remote start ignition wires. Go by car toys, best buy or any car electronics install place and they should have a bin full of scrap wire.

You think I have enough room to get to the harness? LoL

I think you have enough room, just be careful with that ancient drop light.

Hey! :icon_no2:

That droplight is the BOMB! Been in the family for generations! I've dropped that thing countless times and it keeps on tickin!

I tried a newer one a couple years ago and I returned it because it made everything look yellow! New crap sucks LoL