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Strange electrical problem

642 views 5 replies 3 participants last post by  rotate 
#1 ·
I've noticed that in the past few months, I would get in the car and the car won't start. I mean nothing works. Nothing lights up and nothing turns. The dashboard is dark and the radio doesn't work. It's almost as if the battery was completely dead. After disconnecting the ground of the battery and reconnecting, everything is normal.

This has been happening more frequently (almost every other day now), and because I have a quick disconnect on the battery, it's no trouble resetting the power, but I'm worried that whatever the underlying problem is, it won't be reset with mere battery disconnect in the near future.

Any idea what might be causing this? I'm suspecting that there's a major relay that's acting up.

Does anyone have a schematic that may show which relay may be responsible.
 
#2 ·
There is no single relay. The only common point between the starter circuit and the instruments is the ignition switch (besides the battery). The electrical diagrams for most of the main circuits and relays are in the back of the Haynes manual.
 
#3 ·
You are using a "shock" effect to re-energize the system.

Start with the old corroded posi-cable ($100 or so) and go from there.
Inspect using :
Multi-meter (0.0 Ohms all the cables)
jumpers
Probes
Battery load tester ( the battery may be finished)

Even run a redundant ground from battery to engine to body($10 or so)
 
#4 ·
I'll inspect the grounding and power cables. It's been so bloody cold here the past few days I haven't had the opportunity to do some hard troubleshooting.

Fortunately, the problem is occuring with sufficient frequency that I can "catch it" when it happens.
 
#6 ·
This morning the problem occurred again, and thank god it wasn't so freezing so I took the time to diagnose the problem. Wouldn't you know it, the problem was actually being cause by the quick disconnect. I've had this on my vehicle for 4 years without a problem, but the contact area which is not visible during normal operation had corroded. A little sand paper and contact cleaner spray solved the problem.


 
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