Crazy electrical problem...

[The Green GT]

The other day I was driving home at night, and I kept seeing a flash on the dash reflecting on my front glass. When I would look it was gone. Then it started doing it more the next day. My battery light randomly flashes on and off. Atleast I think its the battery light. Its the one all the way to the left. (I ended up with '96-98 gauges on that part, so its a little different.)

Charging is fine, everything is fine, it runs just as good as it did before it started doing this. Plus my aftermarket oil press gauge was freaking out too. Im talking jumping from 0 to as far as it would go so fast it was actually making a pretty loud tapping noise. I pulled my radio out the next day to hook my antenna wire back up, cause it fell out, and I checked the wires I had under there for the gauge, they were fine. So were all the wires under the hood I checked. What do you think this could be from?

 

[HISSIN50]

Could the sender wire be intermittantly grounding?

The battery light could be unrelated. I would check the alternator power cable connections if any of your other electronics act up. Otherwise, sometimes the regulators burp, the belt slips, etc, which can make the light flash for a second.

 

[The Green GT]

Could the sender wire be intermittantly grounding?

The battery light could be unrelated. I would check the alternator power cable connections if any of your other electronics act up. Otherwise, sometimes the regulators burp, the belt slips, etc, which can make the light flash for a second.

Yea, but its not just for a second. It keeps flashing. Sometimes like a damn strobe light. I have a video Ill post up tomorrow.

 

[earleys94gt]

Sounds like something is breaking contact repeatily, then contacting again but doing so fast as to cause the 'strobe' effect.

 

[HISSIN50]

Have the alt bench tested.

If you can make it strobe on demand, we can have you run some tests on the regulator wiring......

 

[The Green GT]

I cant really do it on demand. Sometimes it wont do it, sometimes it will. But I cna sometimes change it or make it stop if I rev it up a little, Im pretty sure its a wire rubbing somewhere, and it moves some when I rev it.

 

[The Green GT]

Video: YouTube - '94 GT possessed.

 

[Chythar]

I'd be willing to bet the voltage regulator on the alternator is dying, and you're getting TOO much voltage into the system. I HIGHLY recommend you get your alternator tested ASAP! If you have too high a voltage coming from the alternator, you can start frying your electrical system.

 

[The Green GT]

Ill go get it tested.

Only thing is the alternator is less than a year old.

 

[Chythar]

If the alternator was a rebuilt one, the voltage regulator is likely the problem. Many shops merely test the electronics to see if they're good, and only replace the bad parts. The rest of the electronics may test OK but may fail within a year or two. This also happens with distributors and the PIP inside - they tend to be re-used and can reach the end of their life sooner than planned.

I used to get rebuilt alternators through my local mechanic and had three of them go bad before the three year warranty was up. After the last I gave up and bought a new one. No problems for several years now.

 

[The Green GT]

It didnt do it at all today. So Im not sure if it is a wire. Seems like the wire would have to be moved alot to not touch at all.

If the regulator was going out would it intermittently cause voltage irregularities? Or would it always do it? Would temperature be a factor? It was warmer than usual today, but it seems that cold would make it work right. I hate electrical problems.

 

[Chythar]

It all depends on how the unit failed. Heat is definitely a factor, but the engine bay still gets nice & warm even on cold days. You could have corrosion or a partially-fried unit; once the resistance gets high enough, the unit messes up. There might be a crack in a chip in the unit, so if the unit happened to be bounced the right way it would intermittently short out.

Got a voltmeter? You can check the alternator output while the engine is idling to see if it's steady at 12v.

 

[The Green GT]

That little tiny plug on the alt was loose. Pushed it back on and it hasnt done it since.

 

[Chythar]

Excellent! Glad it was that easy. Guess we were both right in a way - something was loose.