Hello-
I've been having a problem lately with my 4DR 4WD Chevy Tahoe. Lately it has been completely losing electrical power while driving or sitting at a light. Everything is running fine, then it just shuts off. All lights, everything. When this first started happening, the truck would start right back up. Now, however, it stays dead until I remove the positive battery cable (negative doesnt help). When I put the pos. cable back on, there is enough juice to crank it back up. There is no corrosion on the cables, but I noticed the last time this happened that the positive cable terminal was extremely hot and the stock red rubber around the cable end was starting to melt/burn. Ive had the battery and alternator checked out and they tested fine. Had a general mechanics shop look at it all day today and they couldnt reproduce the problem, so they didn't figure it out either. I've got a nice Optima Yellow-top so I don't think the battery is the problem.

Last summer, the car was doing almost the same thing. The only difference was the terminals were corroding badly. I had the battery check and they said it was bad (another Optima yellow top, only a year old), so I got it replaced. It ran fine until this current problem arose last month.

Lastly, when I bought car 3 years ago, the alternator died and I had it rebuilt to a slightly higher output (to power my sound system, which is now unplugged to eliminate that as the problem). Could this be damaging my electrical system?

Thanks for taking the time to read this. Hopefully someone has an idea of what's going on, but I realize electrical problems are difficult to diagnose, especially over the net.

 

I had a similar problem with my 96 silverado, if you have another car you can and are willing to take a battery out of try switching the bat, my bat was putting power out backward or something like that, it shut off more when I was pulling something but it would just die, on the highway if I was pulling. I also had a bad alt, I had mine replaced though.

 

This sounds like a computer related problem. A good mechanic shop should be able to test it properly. Make sure it gets hot enough while it's being tested so that the problem will reoccur for the tester. The fact that You have to disconnect the battery to make it start means that the computer is being reset when disconnecting the battery. Make sense? It may be a sensor that causes this or the computer itself.

 

uncle bill
I am just curious of your thought, but if the computer reset it should start up again without having to take power away. But my thought would be maybe it is a sensor that is shutting down the engine and when the bat is disconnected it is reseting that sensor or computer allowing to to start again.

 

I've seen many times when a computer malfunctions that disconnecting and reconnecting its power source ( battery ) allows it to reboot. Then it works properly until the original problem reoccurs. It will then again malfunction. It may be a charging system or battery problem and I felt that kcb37 had addressed that issue. Automotive computers are as touchy as PC's and the same problems can occur in both. Once the problem reoccurs, then it will malfunction in the same manner ( IE: heat related or whatever ). I cannot say that this is the problem in this particuler vehicle but if the charging system is up to snuff, the computer is next in line for investigating. Thanks for listening.

 

It could be that the alternator is still bad or probably a bad connection (mis-wired). An electrical short circuit may be causing your problem.

I went to an alternator rebuilding shop when I wanted higher power and luckily until now there had been no problem regarding my electrical system.

 

That's strange it should make no difference whether you disconnect the negative or positive battery cable unless you have something else wired into the electrical system. This could be a second battery or a " cap " for a stereo which obviously store power.


I doubt it's anything to do with any of CU's they wouldn't shut down the electrical system.


I believe this is where your problem lies , the fusible links or probably overheating and opening up. There is too much current draw. You should have this cable checked for integrity.


The vehicle has a large electrical draw as is and introducing a second large draw may be too much for the one battery.
It's not clear if this problem showed up after you installed the sound system. The stereo could be causing the problems if it's a " large high output system " in which case you may look at getting a second sealed dedicated battery for the stereo. You'll need to have a battery isolator installed which will safely distribute the charge from the alternator also isolate the main battery and secondary battery from each other.