Tracing power feeds?
- Thread starter trbojo
- Start date
achalmersman
Well-Known Member
- Joined
- May 28, 2012
Not sure exactly what your looking for. Let me know if your looking for something else
Power Distribution 1
Power Distribution 2 
Ignition
Starting Charging
Power Distribution 1
Power Distribution 2 Ignition Starting Chargingexactly what I needed..thanks! tracing a voltage drop and I need to follow power...
achalmersman
Well-Known Member
- Joined
- May 28, 2012
Great. Let me know if you need any more
There are five feeders that attach to three fuse links (shared links on two pairs). Of that, only one feeder powers the entire vehicle electrical system minus the engine. The second feeder powers the engine electrical system. Then one feeder runs the coolant fans, one runs the blower fan, and one runs the power brakes and high speed fan system.
Voltage drops will occur at the ignition switch, but most commonly, at the C100 bulkhead that feeds the dash fuse panel.
Best choice is to unscrew the single bolt that holds the bulkhead to the firewall, pull the connector out, and soak it in paint thinner to remove the tar from the terminals. Clean it with a brush, then inspect it thoroughly.
My bet is that you'd find corrosion on some of the terminals. It will look like a white or green powdery substance on the surface. If so, it's generally the cause of your voltage drop. There is no real way to repair this; you need to replace the terminals on both sides of the connector. Then repack it with white lithium grease and re-assemble.
I'm sugar-coating it...this is a PITA project, but it's the only way to really fix the problem.
Voltage drops will occur at the ignition switch, but most commonly, at the C100 bulkhead that feeds the dash fuse panel.
Best choice is to unscrew the single bolt that holds the bulkhead to the firewall, pull the connector out, and soak it in paint thinner to remove the tar from the terminals. Clean it with a brush, then inspect it thoroughly.
My bet is that you'd find corrosion on some of the terminals. It will look like a white or green powdery substance on the surface. If so, it's generally the cause of your voltage drop. There is no real way to repair this; you need to replace the terminals on both sides of the connector. Then repack it with white lithium grease and re-assemble.
I'm sugar-coating it...this is a PITA project, but it's the only way to really fix the problem.
Thanks that helps a lot... I started at the starter last night and checked all the fuse links pulled them off and cleaned everything up... Didn't really find anything there... I'm going after C 100 today so you're telling me that only one wire feeds the fuse box and the ignition switch all the power inside the car? The problem is with my alky pump... I had 13.8 volts at the pump connector with the engine running... When I plug the pump in and operate it with the tester it drops to 10 volts... I am powering the alcohol controller with one of the ignition feed spots off of the fuse box....
It's visible and accessible from under the hood. There are dual connectors on it; one for the body wiring, and the other half is part of the engine harness. You can remove the body wiring half (it clips in) to get at the engine harness half. Pull it out as far as you can, and it should give you enough to work with. Drop it in a metal can, soak it in solvent, and brush the tar off.
Remember, the single fuse link feeds the single 12 gage feeder that feeds thru the bulkhead, to the dash harness, to the ignition switch, back thru the dash harness, back again thru the bulkhead via pink/black wires, then finally to the engine electronics. Multiple connections there, multiple potential high-resistance points. Amazing they lasted as long as they did.
We recently did a production run of engine wiring harnesses, mostly sold to counter odd electrical problems within the engine wiring. The harnesses are wearing out, time vs. temperature gets them.
Mother Nature is having her way with us.
Remember, the single fuse link feeds the single 12 gage feeder that feeds thru the bulkhead, to the dash harness, to the ignition switch, back thru the dash harness, back again thru the bulkhead via pink/black wires, then finally to the engine electronics. Multiple connections there, multiple potential high-resistance points. Amazing they lasted as long as they did.
We recently did a production run of engine wiring harnesses, mostly sold to counter odd electrical problems within the engine wiring. The harnesses are wearing out, time vs. temperature gets them.
Mother Nature is having her way with us.
Yep, if the brake booster is in the way, you would be able to get at it easier with the fender out of the way. Still, you will need to pull it as far away from the firewall as you can, to work on it.
If you find that corrosion, post some images. It will likely only be on the red 12 gage feeders.
If you find that corrosion, post some images. It will likely only be on the red 12 gage feeders.
