C4 (88) Electric Guru Needed
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From: Warner Robins GA
C4 (88) Electric Guru Needed
I've been trying to track down some electrical gremlins in my 88 (specifically, my Seat Belt light has been coming on intermittently even though I always wear my seat belt. It goes off if I turn on my lights). I dropped the plastic cover that covers the wires below the steering wheel, and there was a black ground wire completely severed, just laying there.
I know it was ground because I traced one end to a bar that bolts to the inside of the driver's side, near the hood release. That's where it grounds.. the other end goes back behind the metal plate that sits behind the radio, and that's where I couldn't trace it any further. Because of that routing, I'm almost certain it's factory so it has to go to SOMETHING.
I know it's a long shot, but does anyone know what this may be the ground for? I've driven it a couple of days since I fixed it, but my seat belt light still comes on sometimes and I can't tell any difference at all.
I know it was ground because I traced one end to a bar that bolts to the inside of the driver's side, near the hood release. That's where it grounds.. the other end goes back behind the metal plate that sits behind the radio, and that's where I couldn't trace it any further. Because of that routing, I'm almost certain it's factory so it has to go to SOMETHING.
I know it's a long shot, but does anyone know what this may be the ground for? I've driven it a couple of days since I fixed it, but my seat belt light still comes on sometimes and I can't tell any difference at all.
Le Mans Master
Joined: Dec 2000
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From: San Diego, Ca
Re: C4 (88) Electric Guru Needed (Tourney3p0)
Doubt it's the ground. The one you're looking at is spliced to about 30 other devices and the idiot light wouldn't come on at all if the ground was open. Seat belt switch is normally closed. It opens and turns off the light when you buckle up. Switch is in the female half of the seatbelt. Remove the seat cushion or the entire seat to access. It's lead is black, as is the ground. Disconnect the connector and use a DVM to find out what side has 12 volts on it with the ignition in run. Then look for a spot where the insulation may have abraded. My first guess would be that it's grounding against the seat frame causing the light to stay on. If not, jumper the hot side to the connector or plug it back in and buckle the seat belt. Check for 12 volts on the ground side by backprobing the connector. If it has 12 volts, the switch is bad. The other possibility is that the alarm module is bad - it's curious that the seatbelt light would go out with the lights on. Does the "lights on" alarm sound with the headlights on, ignition off? To troubleshoot the module, you'll have to dig into the dash. I don't believe it's in production either so your only source for another one may be a boneyard.
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From: Warner Robins GA
Re: C4 (SunCr)
I don't believe this particular wire I'm looking at goes to the seat belt at all.. It just happened to fall down when I removed the plastic cover. There's still lots of stuff I can do to troubleshoot the seatbelt, but I was hoping someone knew off the top of their head what grounded next to the hood release.
As far as the seatbelt.. it makes the bell sound when I start the car, but not when the light comes on while driving. I also disconnected the wire that goes to the seat belt and goes down next to the console. I drove around like this for a couple of weeks and it still popped up intermittently, so I don't believe the sensor itself is bad since it happened even with the seatbelt disconnected.
It has to be somewhere between the connection at the seatbelt and the dash, so that's what I was trying to troubleshoot. Everything looks good in the dash, so it's probably something shorting out between the center console and the belt. I wish I had the electrical shop manual, but the Helms manual I picked up didn't come with the electrical manual.. that's bit me in the butt more than once now.
As far as the seatbelt.. it makes the bell sound when I start the car, but not when the light comes on while driving. I also disconnected the wire that goes to the seat belt and goes down next to the console. I drove around like this for a couple of weeks and it still popped up intermittently, so I don't believe the sensor itself is bad since it happened even with the seatbelt disconnected.
It has to be somewhere between the connection at the seatbelt and the dash, so that's what I was trying to troubleshoot. Everything looks good in the dash, so it's probably something shorting out between the center console and the belt. I wish I had the electrical shop manual, but the Helms manual I picked up didn't come with the electrical manual.. that's bit me in the butt more than once now.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
Re: C4 (Tourney3p0)
If it's coming on when disconnected, the hot side is grounding somewhere - it's always hot with the ignition on - grounding it completes the circuit lighting up the light.
There are two leads on the ground near the hood release. One has 30 or so devices spliced to it behind the dash. The other lead is directly from the a/c if you have electronic a/c.
There are two leads on the ground near the hood release. One has 30 or so devices spliced to it behind the dash. The other lead is directly from the a/c if you have electronic a/c.
