Thread: Brake pedal pushed in equals lights dimming and voltage drop/car cutting off

K so (ONE DOWN ONE Electrical gremlin to go) anyone had this problem happen?

Everytime im in the car and I hit the brakes the car will drop voltage and then die. Its kinda like when you go to start the car and everything cuts out because the battery cables were loose. Everything will reset/cut off and then come back on once the brake isnt pressed anymore. But the car cuts off. You then have to jump the car to get it back started. But once its started its fine. The voltage just doesnt stay at 14.4 like its supposed to.

This also happens with the car off. I can press my foot on the brakes with the key full turn before starting the car and watch my electronics die out until I take my foot off the gas. Anyone know anything about it?

My electronics were cutting out when I hit the brakes in my p10. I replaced both battery cables and dropped a redtop in... problem solved so far...

Let me post some pre-requisite stuff just in case this will help. Before I figured out my Other elcrical problem. I replaced the battery cables, battery, alternator, checked the obvious grounds, and checked fuses. The problem still persisted. Now that my dashlight/tail light problem is fixed I guess the simple question would be: what could cause the whole cars voltage to drop after being warmed? Also what would cause the car to cut out all the electronics when the brakes are pressed?

vac. leak from brake booster causing the car to stall?

Hi Crim! Na cant be. This has to be something electrical. Plus with the car running it ran perfect and had -20 vacuum like its supposed to. Keep in mind it does it with the car off also. Which tells me its electrical.

I have this problem too.

Seems like the switch is bad, at least one of them. When the switch closes it must be shorting to something causing the strain. Do all of the brake lights work? I would pull the plug on one of the brake switches and try again. If the problem goes away with one or both switches pulled find out which switch it is. It could be the cruise control unit failing as well since one of the switches is to shut that off.

your altenator is going out. Everything will dim when you press the brakes, but seem to go back to normal when you let off. It's def the alt.

Sounds the same to me. I'd even venture that, since you need the jump each time, that your battery has an issue, can't hold proper voltage, and it killed the alternator as a result. Get both checked asap.

Do you have upgraded ground to the block?

Cleaned and retightened the factory grounds?