Grand Prix engine stalls when turn on lights

gunny
Posts: 2
Joined: Sat Nov 28, 2015 5:08 pm

Grand Prix engine stalls when turn on lights

Unread post by gunny » Sat Nov 28, 2015 5:22 pm

My 2004 Grand Prix runs great unless you turn on the lights and step on the break at which time the engine will die. Runs great during daylight hours. Have replaced fuse panel under hood, pcm, checked all fusses, and lights. What's next?

User avatar
carriedi
Posts: 2573
Joined: Wed Apr 10, 2013 12:42 pm

Re: Grand Prix engine stalls when turn on lights

Unread post by carriedi » Sun Nov 29, 2015 1:23 am

wow, that's a weird one. does it happen with just the parking lights on or does it have to be the headlights on. and the brake lights have to be on too?

so, if you hold the brake pedal down while the engine is running and you turn on the headlights, will the engine die right away? If you have the brake pedal down and you turn on the parking lights on, does it die or stay running?

does it die while you are driving down the road and you turn the lights on?

can you tell me exactly what is happening to make the engine die? Need to be very specific so I can try to picture it to see what might be tied together. Parking lights and brake lights are tied together but the headlights should be separate.
Browse "SIMILAR TOPICS" At The Bottom Of This Page.

gunny
Posts: 2
Joined: Sat Nov 28, 2015 5:08 pm

Re: Grand Prix engine stalls when turn on lights

Unread post by gunny » Sun Nov 29, 2015 9:01 am

My car stalls when any lights are turned on and you apply the breaks. Running lights, fog lights, head lights. This will happen when idling or driving down the road. I have noted that if you tap the breaks quickly the car will lose power over a period of approximately 3 seconds and then die. I have pulled fusses one by one for the anti-lock brake solenoid, anti-lock brakes, anti-lock brake motor, fog lamps, parking lamps, and head lights trying to isolate a circuit to no avail. I have also removed the wiring harness on the light switch and jumped the lights to eliminate the switch itself. I believe it must be in the running lights but I am stumped on how to proceed.
Note: if no lights are turned on everything (engine and breaks) works great, if you turn on any lights ,all work and engine runs great but, if you turn on lights (any lights) and step on the break, engine stalls.
This car has been in the shop several times and the PCM, the fuse box under hood, and EGR has been replaced as culprits.

User avatar
carriedi
Posts: 2573
Joined: Wed Apr 10, 2013 12:42 pm

Re: Grand Prix engine stalls when turn on lights

Unread post by carriedi » Mon Nov 30, 2015 2:09 am

I would think that any shop would look at the brake light circuit first. I would look into the running lights and the brake light circuit. Measure the amp draw with the running lights on and then applying the brakes. I would also check for any aftermarket add on parts or accessories. The lighting circuit will look like a good ground when looking for a ground wire connection but when you turn on the lights it will connect to a grounded wire from the add on piece. Check your 5 volt reference when you have the lights on and the brake on.

I would not replace any parts unless I could find a reason why they wopuld be related to the brake switch and/or the light circuit.
Browse "SIMILAR TOPICS" At The Bottom Of This Page.

  • Similar Topics
    Replies
    Views
    Last post