Headlights don't turn on unless engine is off
Thread Starter
Drifting
Joined: May 2000
Posts: 1,712
Likes: 1
From: Seekonk MA / RI border
Headlights don't turn on unless engine is off
A little strange, no?
If I take off and then decide that I should have my headlights on...they won't come on. I have to stop, shut the car off and THEN turn the headlights on. They will now come up and I can start the car and drive.
If I turn them off while the car is running they won't come back on (on occasion they will but most times they won't).
Any ideas?
If I take off and then decide that I should have my headlights on...they won't come on. I have to stop, shut the car off and THEN turn the headlights on. They will now come up and I can start the car and drive.
If I turn them off while the car is running they won't come back on (on occasion they will but most times they won't).
Any ideas?
Pro
Joined: Aug 2010
Posts: 545
Likes: 4
From: Calgary Alberta
Do you have the automatic headlight option? Is it turned on? If so the interior fuse panel has a relay number 44 that operates the headlights. Locating this can be accomplished by finding the fuse panel information in your owners manual.
Thread Starter
Drifting
Joined: May 2000
Posts: 1,712
Likes: 1
From: Seekonk MA / RI border
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
There are only a couple of components in the system. The headlamp/multifunction switch on the column, the headlamp controller on the right forward frame rail directly behind the right headlamp and lastly, the BCM itself which sees the light sensor, headlamp switch and the programming of the twighlight system.
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Thread Starter
Drifting
Joined: May 2000
Posts: 1,712
Likes: 1
From: Seekonk MA / RI border
....but why on earth would the lights come up EVERY TIME if the car is NOT running....but only come up once in a blue moon when the car IS running? I mean, that's bizarre.
Intermediate
Joined: Jan 2023
Posts: 43
Likes: 5
From: New Zealand
Team Owner
Joined: May 2001
Posts: 87,375
Likes: 1,593
From: Western NY
Call me crazy, but I always assumed that the headlight motors weren't strong enough to overcome airflow over the car, when the car is moving, therefore they only open when the car is stationary. Therefore, OP, when you say "the car is running", do you mean the engine is running but the car is stopped, or the car is in motion?
Tech Contributor
Joined: Jan 2007
Posts: 19,470
Likes: 1,171
From: Dyer, IN
Intermediate
Joined: Jan 2023
Posts: 43
Likes: 5
From: New Zealand
Call me crazy, but I always assumed that the headlight motors weren't strong enough to overcome airflow over the car, when the car is moving, therefore they only open when the car is stationary. Therefore, OP, when you say "the car is running", do you mean the engine is running but the car is stopped, or the car is in motion?
Advanced
Joined: Jul 2023
Posts: 94
Likes: 22
From: SW CO
A little strange, no?
If I take off and then decide that I should have my headlights on...they won't come on. I have to stop, shut the car off and THEN turn the headlights on. They will now come up and I can start the car and drive.
If I turn them off while the car is running they won't come back on (on occasion they will but most times they won't).
Any ideas?
If I take off and then decide that I should have my headlights on...they won't come on. I have to stop, shut the car off and THEN turn the headlights on. They will now come up and I can start the car and drive.
If I turn them off while the car is running they won't come back on (on occasion they will but most times they won't).
Any ideas?
Looking quickly at the schematic, in order for the headlamps to come on the Body Control Module must ground the coil of the headlamp relay. Although I agree that diagnosing the circuit with a voltmeter when the symptom is present is the better approach, I would try checking, then removing all fuses that supply the BCM and waiting 15 minutes before reinstalling them.
Please disregard the foregoing as it pertains to the Body Control Module and the Headlamp Relay. Lucky131969 kindly provided a better schematic than the one I referred to. The headlamps should work regardless of the contact status of Relay 44.
Last edited by vito02; Nov 21, 2025 at 08:55 AM. Reason: Error
Tech Contributor
Joined: Jan 2007
Posts: 19,470
Likes: 1,171
From: Dyer, IN
...relay 44 has nothing to do with manually turning on the headlights via the MFS.
....and what does this accomplish? Troubleshooting in a hard fail state is the best way.
Last edited by lucky131969; Nov 20, 2025 at 11:29 AM.
Advanced
Joined: Jul 2023
Posts: 94
Likes: 22
From: SW CO
Advanced
Joined: Apr 2024
Posts: 66
Likes: 18
From: Amarillo, TX
It’s a funny circuit. The open and close signals are on different supplies so it’s possible to have both open and close commands simultaneously if the MFS is sticking. Can have it tested on eBay.
