Simple Wiring Question
Thread Starter
Racer
Joined: May 2006
Posts: 423
Likes: 3
From: New Port Richey, FL
Simple Wiring Question
On my '76, I know that an orange, and a white wire go to courtesy lights. My question is, if one of the wires is disconnected from one of the courtesy lamps, would that make all of the other courtesy lamps fail? If not, what about a disconnected wire on one of the door activation switches? All of my courtesy lights don't work when I open either door, nor do they light up when I turn the headlight switch all the way counter clockwise. Thanks
Pro
Joined: Nov 2016
Posts: 729
Likes: 118
From: Kelowna British Columbia
Likely your ground is disconnected. I think it starts at the door switch on passenger door. There is 12 volts at each courtesy light, glove box light and rear compartment light. You can use a test light or meter to ensure you have 12 volts on each light.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
DUB
Burning Brakes
Joined: Jul 2018
Posts: 979
Likes: 258
From: Maryland
Brian, this is what I did to troubleshoot my courtesy lights which weren't working either.
1. Disconnect the positive and negative lead from your battery.
2. Put an ohm meter across the disconnected battery cables - you'll see a high resistance here - use this as a reference.
3. Open the driver door and push the door switch in/out. If all the wires are hooked up correct and the fuse is still good, then you'll see the resistance drop.
I use the beeper part of my ohm meter here since I can hear it and not have to turn around and look. Do this for the passenger door as well. If both door switches cause the resistance to drop you are good to go. If one door does not, then you can concentrate on that door.
4. If opening neither door causes a resistance drop, then you need to look at the orange feed wire. In my 69 factory assembly manual, page 297 that is
labelled 16 OR from the fuse panel. This feed continues on page 298 where it feeds both courtesy lamp 20 OR wires. BTW this also feeds the
clock and cigarette lighter as well.
1. Disconnect the positive and negative lead from your battery.
2. Put an ohm meter across the disconnected battery cables - you'll see a high resistance here - use this as a reference.
3. Open the driver door and push the door switch in/out. If all the wires are hooked up correct and the fuse is still good, then you'll see the resistance drop.
I use the beeper part of my ohm meter here since I can hear it and not have to turn around and look. Do this for the passenger door as well. If both door switches cause the resistance to drop you are good to go. If one door does not, then you can concentrate on that door.
4. If opening neither door causes a resistance drop, then you need to look at the orange feed wire. In my 69 factory assembly manual, page 297 that is
labelled 16 OR from the fuse panel. This feed continues on page 298 where it feeds both courtesy lamp 20 OR wires. BTW this also feeds the
clock and cigarette lighter as well.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
'jpatrck62'
I agree that your method allows you to test the door jamb switches IF everything is in good working order.
But as like he stated.. this test you performed does not test effect the headlight switch is doing on the circuit and why it is not working.
YES...if he employed your test and turned headlight switch **** to see what the resistance is this would give him more information. But seeing how it is not working it will require a bit more investigation and possible disassembly where he can actually check the wires themselves and see if they are not cut or broken and cause this circuit not to operate as designed.
The GOOD thing about this circuit is it is an easy circuit to diagnose with few wires to test and check.
DUB
I agree that your method allows you to test the door jamb switches IF everything is in good working order.
But as like he stated.. this test you performed does not test effect the headlight switch is doing on the circuit and why it is not working.
YES...if he employed your test and turned headlight switch **** to see what the resistance is this would give him more information. But seeing how it is not working it will require a bit more investigation and possible disassembly where he can actually check the wires themselves and see if they are not cut or broken and cause this circuit not to operate as designed.
The GOOD thing about this circuit is it is an easy circuit to diagnose with few wires to test and check.
DUB
Burning Brakes
Joined: Jul 2018
Posts: 979
Likes: 258
From: Maryland
Yeah, I see what you mean - I did that because he stated that nothing worked at all.
I probably should have started with #4 first because he stated that none of his lights worked - so if his clock and cigarette lighter don't work either I
thought it wise to check the main feed from the fuse panel first.
I probably should have started with #4 first because he stated that none of his lights worked - so if his clock and cigarette lighter don't work either I
thought it wise to check the main feed from the fuse panel first.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
Yeah, I see what you mean - I did that because he stated that nothing worked at all.
I probably should have started with #4 first because he stated that none of his lights worked - so if his clock and cigarette lighter don't work either I
thought it wise to check the main feed from the fuse panel first.
I probably should have started with #4 first because he stated that none of his lights worked - so if his clock and cigarette lighter don't work either I
thought it wise to check the main feed from the fuse panel first.
A guessing game in full force is kind of like when I am install a used VATS system off of a C4 in a car and not knowing what the value of the chip in the ignition key is in order for the VATS module to allow the engine to crank There are values from 1 to 14. I flip a coin and either start at 14 and use my tool and work my way down to 1...or start at 1 and work my way to 14. And having to wait about 8 minutes after each failed test...sometimes I start at 1 and the value of the VATS module is a 13...and ONLY IF I had started at 14 and went back to 13. I would have saved all that time. So...a guessing game nonetheless.
DUB
Thread Starter
Racer
Joined: May 2006
Posts: 423
Likes: 3
From: New Port Richey, FL
I will check the bat cables for ohms. The cig lighter and clock do work. The BAT terminal on the fuse block is hosed, and I had to run a single wire all the way back to the battery itself. When I done this I went behind the small access panel in the driver's rear wheelwell. Thus, I was also flogging around in there with a right angle drill to run it, I might have loosened some wire to the driver's door switch, as the wires for that do run through there. I swear, if there ever was a curse to this car it would be that of the electrical wiring through out this thing. It's been a nightmare from the day I bought it 24 years ago. If I had the time and funds I would properly gut the whole damn wiring system, and replace with new.
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Thread Starter
Racer
Joined: May 2006
Posts: 423
Likes: 3
From: New Port Richey, FL
The fuse block like I previously said is junk, as well as the rest of the electrical system. So I had to run another independent wire with an inline fuse to the orange wire at that location. The electrical system I have my doubts about, but I don't want to tear the whole car apart at this time to replace it.
