Electric Problems

[JIMOCO]

Realizing that electrical problems can be difficult to diagnose, I thought maybe one of you may have had a similar experience and found the cause. I have a MKIV and used the Ron Francis harness, battery cut off and speed hut gauges. No mods. For three years all was good. When I turned on the ignition the gauges would reset and then I would turn the key to start. Recently, the gauges sometimes did not reset until the car started but all was working fine. Lately, I have randomly had the gauges not reset until the car was started and began to move. Sometimes all is normal. Assumption is a loose wire that I have not found. On Monday, my oil temp gauge was reading fine then dropped to zero. I looked again and it was back to normal then later, back to zero. Checked the wires between the sender and gauge and all looked good. Yesterday, I turned the key and no gauge response then turned to start and heard a click. All electric dead. This included the courtesy lights, clock and under hood lights that are separately wired and fused from the ignition. Then I noticed the under hood lights were very dimly lit. OK, must be a dead short somewhere. Checked every fuse and nothing blown.

I checked a few things, tried the phone a friend approach and decided to disconnect the battery and look further when I had more time. Before disconnecting the battery, I returned to the car and noticed the under hood lights were shining bright. Tried to start and it fired right up but still no gauges. Not trusting that the issue was a fluke I disconnected the battery and continued to look for an issue.

I do not trust the electrics now and do not want to risk any damage so I have left the battery disconnected. My first thought is maybe a bad ignition switch but that is just a guess. Has anyone had a similar issue and found a solution?

[Big Blocker]

There have been numerous posts about bad ignition switches lately, you might want to do a search for those as a reference.

2nd question; what battery are you using . . . cells going bad are a reason for intermittent electrical issues.

Doc

[Itchief]

Bad or loose grounds cause a lot of strange/intermittent electrical issues you may want to check out the ground for the gauges

Rick

[Boydster]

I was going to say grounds. If at one point the engine wouldnt even turn over, check engine to frame ground and frame to battery.

[seagull81]

Have your battery load tested at the parts house. Goofy batteries do crazy things.

[Kilner]

There are many possibilities but don't drive yourself nuts looking for a busted wire somewhere in the harness YET. Always check and recheck the basics. fuses, battery load test, all main power AND ground straps/cables, alternator voltage output. Your many issues in many different areas suggests a main power source issue. Good luck!

[JIMOCO]

Thanks for all of the replies. So far I checked all fuses, checked and tightened the engine ground and battery grounds. Adjusted the connections to the battery cut-off. I checked all connections behind the dash. I have not yet found the issue. Everything appears to be functioning normally at this time. I have not been able to get a repeat failure. I am leaning now toward an issue with either the starter or ignition switch because the system shut down immediately when I tried to start the car. Although neither are showing any indication of an issue and I did not see any smoke at either location.

For the oil temp issue I have an extra sender that I will swap and see if that makes a difference.

I have an Optima Red Top and will have it and my alternator tested. Thanks again. I hate electrical gremlins!

[Boydster]

Oh, you have a battery cutoff? Install a temporary volt meter right after the cutoff (not the battery side, the car side) and watch it the next time there's a failure. Those things do go bad... especially the Chinese ones. A drag car I used to crew on many years ago used to eat em up like a kid in a candy store. Once they got away from the Chinese made units... no problemo.

[JIMOCO]

I thought about the cut off but I have some things on their own fused circuit directly to the battery. They went out as well. Could the cut off cause a dead short? I am thinking maybe a short in the starter solenoid. When I was having the issue I had 14 volts on either side of the cutoff.

[Fixit]

Time to be negative about this post (pun intended :D)

Reply #9 states that even your direct connect hot feeds (not on cut-off) went dead as well. This is telling me one of two things:

- Your "main" ground off the battery to the frame is questionable. It should be tight, metal on metal, with a star-washer under it to bite in. (no paint, PC, etc.) You should also have a ground strap from the engine block to the frame as well.
- There's something wonky with the battery itself... Do you have another battery around you could temporarily rig? (Even sitting outside the car using jumper cables - do it safely!)
Pull the battery and have it load tested at the parts store. Hopefully they'll have a "toaster" - the rig that REALLY puts a load against it. Have 'em nail it a few times and see if it fails and how fast it recovers.