Contour Enthusiasts Group Archives Forums General Troubleshooting Car dies when headlights turn on

Here's a wierd one for ya:

I have a 1995 Mystique, 2.5L manual 5-speed. 184K miles.

Last week, my car started intermittently doing this -it starts OK, then when I turn the headlights on it dies.

Even wierder - I turn the heater on and the windshield wipers come on. The fan comes on at half-speed. Also, the tach goes to 0 and the speedo jumps up to 110. The engine runs ok at this point, but the electronics are whacked out. If I turn the headlights on, the engine dies immediately.

I'll drive it for 10-20 minutes, then I'll here a "click" and everything is OK again. Headlights, heater, wipers, everything is normal.

It's happened twice in the past 2 weeks. It never ever happened before (I've owned the car 4 years).

Obviously an electrical problem - but does anyone have a clue about where to start looking? I'm wondering if the car battery has lost a cell... or if a sensor is shorting out. Or maybe something else?

Thanks for any advice.

I'd look at the battery first. My car did funky things like that with a bad battery a few years ago.

Good luck!

Jeff

The battery could be shorting out. These cars do really funky things whent he batterys are dying. And yes, the car can and does start OK in some of the se cases. You could have a bad alternator. You could also have a bad or dirty battery cable. If the battery checks out ok you should check the ground bolt that is under the battery tray. I've seen them get corroded and cause sparatic electrical problems. Worse case is a bad wiring harness. It is a 95 and I've had several with bad harnesses.

I kinda have similar problems couple weeks ago, I went and got the battery and the chargin system check at a locol shop, they recommand to change the battery and the alternator. they should be able to do that for free (check with autozone or pepboys

like most people here say, round the time that your battery/charging system goes bad, crazy stuff happens.

but i only change the alternator knowing that my battery might be able to last a bit longer (which i'm not sure if i should do that or just replace the battery too).

sounds like some wires are a little mixed up. You don't have any buddies that have touched your car lately have you? Thats sounds like something my friend bryan would do.

I brought it to a local shop yesterday. They disconnected all the electrical connectors under the hood and cleaned all the contacts, and put everything back together. They found a bad ground on the wiring harness connector to the dashboard.

Car runs great now. I was also surprised to see that my dashboard lights are now much brighter! Obviously the connection had been bad for some time.

Cost me only $70.