pop99

A good friend of mine just called and told me his 99 Dodge has electrical problems. He says when he turns on the headlights the engine dies. Also when he steps on the breaks it dies. He was told the brake light switch was bad. He changed that with no change, and is now looking at the headlight switch. Someone else said that the battery is weak and to get a new one.

He just had a new baby so money is a little tight. Any help would be appreciated.
Thanks,

Barry

natstayl

So deliver new batteries to him/her! Not trying to be coy, employ some of your racin buddies, they might want to help. Most all of us have found ourselves on the bottom ourselves, once or twice. Maybe one of these days he/she will be able to return the favor, maybe not to you but somebody.
Nat

BigBlue

If the battery can crank the truck, then I doubt it's that. It takes a lot of juice to crank these trucks.

Tom Bolitho

I would check the engine ground connections. It could be back feeding when the lights are turned on and not allowing the engine to ground.

pop99

Tried a new battery, no difference. The truck even dies out when you put it in reverse. It seems like whenever a light bulb comes on it kills the engine. After calling several dealers one finally said he thinks it is the computer. We're going to try and take it in on Monday and hook it up to their computer and see what codes come up.

nitrousn

with the truck running try to do a wiggle test on the wires and see if you can duplicate it. i saw one with a tilt column that would die with the column all the way up. the wires were loose on the ignition switch causing the problem. what does the voltmeter read ?

pop99

we've had the dash all apart and checked all the wiring. Checked the grounds too. It seems like if you turn on the headlights, backup lights, or break lights for some reason the engine dies out. We managed to drive it with the 4 way flashers on but everytime the lights would flash the engine would die out. When the lights flashed to the off position the engine ran fine. Have never seen this problem before.

nitrousn

what is the volt meter reading and what does it do when it wants to die out?

pop99

I'll try and check the volt meter tomorrow and let you know. Thanks to all

Barry

Mexstan

Is that 99 Dodge a diesel or a gasser? If it is a gasser then the diagnosis takes a different approach.

pop99

Guess I forgot to say, it's a gasser.

Mexstan

New game if it is a gasser. My guess is that you probably have an alternator with a weak output. Get a voltmeter and check the voltage on the input terminal of the ignition coil with the lights off. Then turn the lights on and see if the voltage drops. If it drops, then have both the battery AND the alternator checked. Let us know what you find.

pop99

Yesterday we swapped batteries twice and took the alternator to the local auto parts store to be checked. They said there was no problem with it. We didn't get a chance to mess with it today.

Mexstan

OK, that eliminates those possibilities, but you still need to do that coil voltage test. It will only take a couple of minutes to do. Report back the voltage readings you get with lights off and on.

pop99

Thanks, I'll try and get my friend tomorrow and see what we can do with the coil test.