Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Car loses power when braking or signaling

I drive a '91 Corolla, 5 speed with the 4AFE motor. Recently when I apply my brakes or turn on a signal, the power momentarily cuts out. By this I mean the clock and radio stop working. It only happens for about 1 second and comes back on, even if the brake pedal is still depressed or the turn signal still on.

This is the first time it’s been consistent, but it started acting up about a week ago when I lost power a few times (I can’t remember exactly but I don’t think it was under the same conditions with the brake pedal.) And then it actually died and I was able to start it again. Yet, when it died my dash lights came on instantly, which makes me think it’s a separate issue (And won’t a car still run without power once it’s going, if the alternator is ok?) Alternator has roughly 5,000-10,000 miles on it and there are less on the battery FYI. Any questions feel free to ask.

Thank you!

This is probably a simple electrical problem. Braking or signaling both demand slightly more current to power the bulbs. Check for a loose or corroded battery terminal, connection at ground or starter, weak cable ends, or badly corroded battery cables. If everything appears to be in order, you may want to replace the battery cables. They can corrode inside the insulation and cause intermittent problems like this.

Thank you for your input, and I apologize for not getting back sooner. It appears you were correct. I ended up taking it to an electrical place and they just cleaned all the connections, put lock washers on, and put some kind of yellow gunk on the connections. Haven’t had a problem since. Thanks!

if your idea about a car continuing to run without power because the alternator is “OK” how would you turn the car off? I am just trying to make you think of the order of how things operate.

To me it sounds like a relay problem somewhere. Sorry I can’t be more specific. Maybe a ground for the relay.