1994 Buick Lesabre - Headlight Issues

[Matt M.]

I have 1994 Buick Lesabre that the headlights will not shut off when I press the switch. Typically this happens after the car has been running for appx 20-25 minutes. The switch operates fine and turns the lights on and off fine until the 20 minute mark. I've disconnected the switch from the wiring harness in the driver's door and the lights still stay on. This makes me believe there is a relay switch located somewhere else. I can hear a clicking noise from under the dash when I press the switch - assuming relay or solenoid. I've looked on Chilton's online repair manual at the wiring diagram. It appears the wiring harness runs into a "Light Control Module" but I don't know where this is located. I'm assuming this is where the clicking is coming from under the dash. Does anyone know where this is? Or have any other suggestions? Any help would be much appreciated. Thanks!

[spinne1]

It is directly above the fuse box and is in the same piece of plastic that holds the fuse box. You can see it if you look above the fuse box. It is not THAT hard to remove (but isn't super easy either). You don't need to disassemble the dash. You simply need to push the LCM up, then outward. You may need to do some aggressive wiggling as you do so, but it can be done. It is attached with two wiring harnesses. One you can remove by hand. The other has a 7mm bolt holding it. (you would remove the wiring harnesses after removing the LCM from its location)

The LCM is either black or brown plastic and is a rectangular box about 5 inches long, 3 1/2 inches wide and 1 to 1 1/2 inches tall.

Don't pay for one new. Get one from a junk yard. Expect to pay $50 or so at some junk yards, but only $10 at a pull-a-part type place.

[Matt M.]

I'm back with the same problem again. Honestly, I never fixed it to begin with... the problem comes and goes. Usually acts up for about a week or a little longer and then it stops and works well for about a year. I honestly do not know where to start. I followed the previous poster's directions; however, the LCM appears to be nothing more than a wiring harness that separates. I disconnected the two and sprayed electric connector cleaner and put it back together. Problem still exists.

Anyone else ever experience this? Headlights won't shut off. Even when the switch has been disconnected from the car. Somewhere there's a relay switch sticking - I just don't know where its located at in the car.


Thanks

[spinne1]

Originally Posted by Matt M.

I'm back with the same problem again. Honestly, I never fixed it to begin with... the problem comes and goes. Usually acts up for about a week or a little longer and then it stops and works well for about a year. I honestly do not know where to start. I followed the previous poster's directions; however, the LCM appears to be nothing more than a wiring harness that separates. I disconnected the two and sprayed electric connector cleaner and put it back together. Problem still exists.

Anyone else ever experience this? Headlights won't shut off. Even when the switch has been disconnected from the car. Somewhere there's a relay switch sticking - I just don't know where its located at in the car.


Thanks

Either the 94 is different from a 92 or you didn't find the LCM. The LCM is a plastic box. It is attached to the same piece of plastic as the fuse box. It is about 90 degrees from the fuse box when the fuse box hangs down. It slides either up or down the plastic "bracket" holding it to release it. It has two wire harnesses running to it. To see it, lay on your back on the floor with your feet over the seat with a flashlight. Look directly above the fuse box with it hanging down. Do you see a plastic box? If not, the 94 has a different design and I don't know how to fix that.

[Matt M.]

Thanks for the reply. Yes, I've been there and I feel I've located it. 7mm bolt dead in the center of it as you described in your first post. I've loosened the bolt and separated the front wiring harness that included the bolt – I’ll call this the female end from the box containing the male prongs. The box you reference is actually white in my ’94, but the wires are running directly out of the back of it. I do not see another wire set or harness to disconnect from this white box. I feel confident this is the LCM b/c when the two are disconnected the headlights will not come on. Any other suggestions?

[spinne1]

Originally Posted by Matt M.

Thanks for the reply. Yes, I've been there and I feel I've located it. 7mm bolt dead in the center of it as you described in your first post. I've loosened the bolt and separated the front wiring harness that included the bolt – I’ll call this the female end from the box containing the male prongs. The box you reference is actually white in my ’94, but the wires are running directly out of the back of it. I do not see another wire set or harness to disconnect from this white box. I feel confident this is the LCM b/c when the two are disconnected the headlights will not come on. Any other suggestions?

That's not it. It does not have a 7mm bolt dead in the center. It has it in one of the two wire harnesses. (Each harness is not that big--they hold 6-8 wires each or something like that.) It is not square.