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Discussion Starter #1
I have had the back lighting for the headlight switch going off and on for the last few weeks and finally today had the time to replace the bulb (LED) with a different type and now it doesn't work at all. I checked power between the ground (black wire) and hot (red wire) on the back of the headlight switch and I don't get any voltage at all. All headlights and interior lights work including the dash cluster illumination lighting. Anyone have a good schematic to look at. I've taken a look in my FSM's and it's hard to understand where the headlight switch is since i'm not seeing a black or red wire where it says "headlamp switch". Looking at the headlight switch as seated in the drivers seat the black wire is the furthest to the left in that connector and the red wire is the 3rd from the left. I have already verified continuity from the light bulb socket end to the electrical pin on the back of the switch and all is good there. Need some help guys.
 

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You probably know , but just in case, I am 99% sure the headlamp illumination light is powered through ign on, not dash lamps. ( on all the time lights on or off)

As you say the manual is less than helpful .

I went to check mine to see which fuse , and low and behold, my lamp is not working :(


I "think" it is fuse #11 powering through splice S232 ---------B4 on C200----------- splice S255 ------------ to headlamp terminal "F" but not 100% sure
 

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LEDs only work with one polarity. You may have the bulb in backwards. NO JOKE.
 

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Discussion Starter #6
I've already looked at those schematics as well and unless I'm wrong on the wire coloring on my switch connector that is different. I'm going to pull the lower dash back apart at lunch and get some pics and also reference the connector wire location numbers/letters.
 

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I "think" it is fuse #11 powering through splice S232 ---------B4 on C200----------- splice S255 ------------ to headlamp terminal "F" but not 100% sure
95 Wagon

Same as what I found in my 94 FSM "fuse block details" So it is a "hot in run" circuit.

This is what I had when I did the flash to pass. The plug is from the back(wire side) (1994 Caprice)

A Empty
B To Twilight Orange 18ga
C To Markers/Dash Dimer Fuses #41 #42 #43 Brown
D Headlight Switch Illumination Bulb Ground Black
E Power To Headlight High/Low Switch Yellow
F Headlight Switch Illumination Bulb Power Fuse #11 Pink
G Breaker Power To Twilight/Daytime Module Dark green/White
H From Exterior Lamp Fuse #31 Orange 16ga
J Empty
K From Fuse Link Red
 

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Discussion Starter #9 (Edited)
Ok, had a chance to mess with it at lunchtime and it turns out it's a bad ground. Now I just need to either chase the ground wire (should be left A pillar behind kick panel) or run a new ground wire. I'll start off by checking for a clean and tight ground bolt.
 

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Discussion Starter #11
Ok, I still can't make heads or tails with the wiring diagrams in my FSM. Here is a pic of the connector at the back of the headlight switch. Location D is a either a black or brown wire which I have determined is a ground for the light in question and has a break in it somewhere. Location F is the HOT feed for the light. Any help is appreciated. I would assume the black or brown wire just goes directly to a ground source via a ground junction somewhere? If that's the case I can just run a new ground wire directly to the connector although i'd much rather locate and repair the issue.
 

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I am working from a 95 manual

You should be able to find in a similar area of the 96 book
I am in 8A-14-2
Ground distribution G200


Splice S201 is supposed to be behind center of cluster " center of spiral taping"
Good luck getting there with the dash in .
That said I really doubt that slice would be the issue

So you are saying everything BUT the headlamp illumination works and if you stuff a ground wire in the back of terminal "D" of the HL switch then the little illumination lamp works as well ?.

Have you tried tugging a bit on that wire to see if it is stretchy like the copper is broken inside, near the plug?

If you look in the manual, after the S201 it is a round about route to the A pillar ground .
Involving connectors 201 B and c 202 B ( that is the jumper for Twilight sentinel )
They are to the right of the steering column near the big C200
 

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I would assume the black or brown wire just goes directly to a ground source via a ground junction somewhere? If that's the case I can just run a new ground wire directly to the connector although i'd much rather locate and repair the issue.
Attached is a pic from my 95 Schematics PDF file I bought years ago. IT looks a little different from the FSM schematic. In the upper left corner of the pic is the Headlight switch Bulb and yes this bulb is lit all the time through the Ignition on.

It sounds like you have traced it to a faulty ground and as Wagon mentioned, there are a lot of grounds tied together in the harness and the break could be anywhere in the wire. If it were me, I may just pierce the wire about an inch or 2 from the connector and see if you can find ground there. If not, it may not be worth your time trying to find the break and fix it. Instead, I would just cut n splice in a new wire and run it down to the same area of the kick panel rather than tearing into the harness/dash and trying to find the break. I would say, be sure to pull the kick panel and inspect the wires/ground for any looseness or breaks first.
 

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Attached is a pic from my 95 Schematics PDF file I bought years ago.
I take it that is not a GM file?

Does not show slice numbers or position

Does not show connector numbers which are different depending on base, Twilight sentinel, DRL
 

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I take it that is not a GM file?

Does not show slice numbers or position

Does not show connector numbers which are different depending on base, Twilight sentinel, DRL
That is correct, as I indicated before this is just a series of Schematics that I purchased for about $10 years ago from an online service. It is 50+ schematics of different circuits on the car and is in one .PDF file so it is easy to access.

Not sure where they pulled the schematics from to build this PDF but it comes in handy from time to time. It is a little different even from the schematics I've seen up on GoldSSWagon site. So it gives you a different perspective of what I may find on his site or even in the FSM. I have the FSM's for my car (95) but very seldom use them. Attached is the first page which just gives you a rough idea of how this is setup but it is really convenient to use.

I will say that in some of the schematics like the HL circuit, it does show the Connectors and which color Wire goes to which pin of that circuit. Used these back when I was wiring up my Pwr seats, Mirrors and others that were added and I had to make up harnesses for.

As far as the Splices are concerned....I've seen these in some of the smaller circuits and how GM chose to do this. If those slices are buried in the harness anywhere with a bunch of wires, I'd leave them alone and just run a new wire in parallel to the existing harness. I would not tear into the factory harness and possible disturb other wires for just this bulb. Just like when installing Pwr seats and Mirrors, those circuits were tied into the overall harness and a mess to get to. Instead, I just to just get the pigtails for both ends and create a Sub-Harness for each and run it in parallel to the existing harness.

Attached is page 1 from the PDF schematic file I have and gives you an idea of how the PDF file is structured.
 

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