My car dies when the brake pedal is pushed

[weisserguy]

I have a 97 SL1 automatic under 90k. The other night the car wouldn't start, totally dead battery. I got it jumped and it idled just fine, however, once the cables were removed and I was going to drive around to charge the battery, I pushed the brake so I could shift into gear and the engine died. Jumped it several more times and sure enough the engine died each time the brake was pushed.

I checked the charging system and with the car idling, disconnected from the jumper car, the voltage across the batt was 14.4. I checked the cables leading from the batt. and they all look fine, also evidenced by the good voltage.

I got on here and did some research and found similar threads but they are for a 94 and a 96 I believe. I checked for the ground in the trunk but the only thing that looked similar was a connector that looked absolutely fine, and it wasn't in an area that would really promote corrosion, it was halfway up the trunk wall.

So, my question is...where do I look now? All the grounds I could see looked fine. And what would cause the battery to die like that? The car worked fine the day before.

[2teendaughters]

Check the brake booster for a vacumn leak. If the diaphram is gone the massive leak when you press the pedal could cause it to die...

[weisserguy]

well, just got back in from tinkering. The car didn't die from the brakes this time. One time it died from the headlights being turned on, then it died twice from the brights. However, at one point in time, the brakes were on, the headlights and brights were on as well as the hazard lights and the car didn't die at all until the brights were turned on and off several times, then died again.

[wrenchtnr]

I think your battery is trash. How old is it? With the engine off what's the voltage? Then turn on the headlights and check the voltage.

[paterson]

battery or terminals poss serp belt or tensioner

[1995sl1sohc]

I would have the battery tested it sounds like it is junk to me.

I had a similar problem, it would stall when I would use the power windows or put any kind of load on it. The alternator, starter, and battery all tested fine, so I went over all of the wiring between everything it checked out fine. So I figured it had to be the battery so I undo the battery bolts to change it and I find a nicely stripped battery bolt that was getting really poor contact with the battery. I replaced the bolt and haven't had a problem since.

[weisserguy]

The battery turned a year old this month, and I live in Sacramento, Ca. Far from an extreme climate. But there is hardly any voltage across the battery when off. I'll take some voltages with the car running when I get home.

[1995sl1sohc]

The battery is junk, see if it is still under warranty. It should read 12 volts with the car off and 13-14 volts with it running.

[weisserguy]

Well, just took the battery to the parts store. Clean bill of health. 12.5 volts and 615 cold crank amps.

Where to check now...alternator? would it be the alternator if the voltage at idle is 14.4v?

[OldNuc]

No, 14.4 at idle would say the alternator is good and the battery test indicates that the alternator also has adequate output power. When you hit the brake there is a large current draw on the electrical system. If the battery is dead as yours was, and still might be, Then that current draw my drop the system voltage low enough to shut off the car.

To take the battery out of the equation you should put the battery on a slow charger for 12 to 16 hours. One of those 2 amp trickle chargers and 24 hours is even better. then if after a good slow charge you still have a stalling problem when you hit the brake further searching is in order. First get the battery fully charged.

[Growser]

I'd give OldNuc's idea a chance or switch out the battery from another car. Once you've ruled the battery out I'd check your battery cables next for corrosion.

[ahimsa1]

One possibility is that your side-terminal posts are coming loose or the threads are a little stripped so that they work ok when adapters are screwed in at the store for testing purposes, but they don't make a good connection when your battery cables are connected in the car. I've had that happen... had to replace a GM side-terminal battery battery due to the connectors on it going bad. I'd hook up another battery (using jumper cables to make it easy) and see what happens. Good luck!

[weisserguy]

Hmm...didn't think about that, but the car seemed to run fine until the jumper cables came off, then it was a matter of time for the car to shut down.

However, when I was taking the battery out to get it tested, none of the terminals were loose and were fairly snugly torqued in there. I have it on the charger now though.

I guess i'll give the cables a try if the charging doesn't work. Actually, I'll probably change them soon anyway.