Seems like there are alot of electrical problems these days, so I thought I would throw this little oddity in. Its not really a big problem, just a curious question. I have an 87 Trans AM with a 305 TPI. Everything works fine electrically. When Im driving at night, and I have all my lights on, they stay bright, and dont fluctuate too much. Only when I hit my brakes, they dim for about a half a second. I assume thats normal from the added drain of all those brake lights. The weird thing is, when I floor the car, and it gets up to redline territory, my lights all flicker. They get dim, then bright, dim, then bright. This happens really fast. Outside lights, inside lights...all of them. It only happens under WOT when the motor is almost wound out. Anyone else notice this happening??? Anyone willing to test this on their car to see if you notice it. I only notice it cuz Im one of the most **** people when it comes to my car. Let me know what you all think. Not an emergency, just a curious little problem. Thanks
Justin

 

Sounds like your alternator or just the voltage regulator might be getting flakey.

 

thanks...yeah i thought of that. Actually i was assuming the alt was going bad. Since its internal regulator...even if its the reg, new alt. is the fix anyway. I had it tested by autozone not too long ago, and they said it all tested out fine, but then again it wasnt at WOT when they tested it. Then again...what do they know? haha. ill have to check it out. Ive gotten suggestions before about a bad ground, but goodness, it could be anywhere. I cant exactly go crawling around the engine bay or under the dash while the car is at WOT to find the problem. Oh well, maybe Ill swap a new alt in and see what happens. Ill have to run my car at WOT at night to test it...damn......the sacrifices i make thanks again tho
Justin

 

You know, I had an odd problem a little bit similar to this.

When I floored it, my voltage gauge would hit the red.

On the back of my alternator, where the nut connects the positive wire to the battery, the bolt this nut screws on to was loose from within the alternator

I tightened the bolt, then put the wire and nut back on, and it solved the problem. Didn't even take off the alternator to do it either. Not sure if this is the same thing or not though.

 

It sounds like the battery negative cable is loose either on the body or the battery. When you brake or go fast any loose connection is more likely to be vibrated and make an intermittent or poor connection. If it was just the braking circuit with a fault it should only affect the rear lights and indicators.

Check for corrosion where the earth wire meets the car body.