Reoccurring electrical issue

[Jase21]

For months now I have had an electrical issue with my 92 MTX. When I open the door everything is fine until I turn the key to start the engine. At that point, everything cuts off including the interior clock. I have tried several remedies but nothing has worked so far. I replaced the battery terminals, and the battery itself. I am beginning to suspect the altenator, but when I bought my new battery, I was told that the problem could be a short in the wires? At this point I am stumped.

 

[itwonder]

Make sure the battery is fully charged. It should read around 12.7 volts. You can buy an inexpensive voltmeter at Walmart if you don't have one. Replacing the terminals may not have been enough. You may need to replace the positive and negative battery cables.

Try opening the door and turning on the headlights on bright. Is everything still fine? Are the headlights full brightness?

Is there a click or any noise when you turn the key to Start? It is possible the problem is in the starter if everything else checks out.

 

[Jase21]

The battery was brand new. When I tried to jump it nothing happen. When it occurred before it would click weakly then fade out as if the power were fading away. Right now everything is out.

 

[rubydist]

sounds like a short to me.

put the volt meter on the battery and watch it as your assistant turns the key to 'start' if the battery voltage drops significantly (1.5V+) that suggests that you have a short. it could be the starter, as was suggested earlier, or it could be in the key switch or anywhere between.

 

[Jase21]

The problem reoccured again which cost me three days of missed work. I was able to run the car ofter tightening the terminal bolts on the negative cable. My neighbor had a charger with the voltmeter on it. While I was charging the battery I noticed that the meter was showing a charged battery so that outage is not caused by the battery. The second time it went out which was this past weekend, I tightened the bolts on the positive cable, but at this point, I know it will probably happen again. When it happens again I may have power until I turn the key to start the car when I hear a click and everything goes out.

 

[silver93sho]

Definitely sounds like a shorting issue. You would need to get the wiring diagrams for the starting system, trace the wires that come into play when you turn the key to start and start to narrow down wiring or components. sitting here at work i really cant give more info than that but i would work from key on(start) wire(s) forward. Electrical troubleshooting can be a PITA but by ruling out things in an orderly fashion you'll find the issue much faster, rather than throwing parts at it. Don't immediately rule out component problems either. read your diagrams and see what relays or other things are in the loop during the starting process. Also, are you using the cheap terminals that u screw to the battery cables? if so, those things suck terribly. i did a quick negative terminal replacement with one of those and it caused the same problems, clicking during start and acting like a dead battery. they don't stay tight at all. replace the entire cable, from battery terminal to starter and negative ground with the ones that are already crimped and do both of them at the same time.

 

[93rev2sev]

You need a new starter.

 

[St Louis SHO]

Could be a bad ground. Take jumper cables and use the ground side from the battle post to the engine lift bracket and see what happens.

 

[rubydist]

I would take the cables off the battery and do a good job of cleaning them up. then I would take a hard look at the cables where the terminals attach. since you said that tightening that helped you, I suspect that there is corrosion in that connection too.

I have had battery terminals that looked fine, but had a thin layer of corrosion that made the battery look charged, but it would not flow enough current to start the car.

 

[luigisho]

I've experienced the above as well.