Headligh Experts Needed
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 844
Likes: 46
From: Southaven MS
Headligh Experts Needed
My drivers headlight will not go up or down. I have used the search feature and checked the connections, replaced the gear, unplugged and reconnected the control module, and also checked the wires at the back of the headlights to see if im getting 12+ on both wires. Everything I have checked so far has been fine. I need to know what to check or replce at this point. Please help.
Cruising
Joined: Aug 2006
Posts: 14
Likes: 0
If it is your motor try this turn the switch on tap on head light motor with something like a screwdriver handle. If it is the motor it will sometimes still have enough left to work a few times more. Then you would no for sure it is the motor. Also you could just get a new one without installing it plug it in if it works install it if not you no you still have not found your problem return it.
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 844
Likes: 46
From: Southaven MS
I'll let you know on the motor. I want to check a few other things before I start replacing parts. I do think it could be the motor or control module. I just want to see which it is. Thanks
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Drifting
Joined: May 2000
Posts: 1,917
Likes: 3
From: Southern NH
Another way to check the motor is as follows:
The logic here is if you disconnect the headlight motor from the car and apply a direct +12V across the connector wires it should raise. The Control Module does just that except it keeps +12V on both wires and then switches the ground on the appropriate wire (hence applying +12V or -12V across the 2 wires) to raise or lower the headlight.
- Unplug the connector just behind the headlight to disconnect the headlight from the car's electrical system.
- Identify the 2 wires that control the motor. It's the Light Green/Dark Green on one headlight and Light Blue/Dark Blue on the other (i can't remember offhand which is which side, but the other 2 wires are the same color on both sides).
- Get a +12V separate power source if you have one (or rig something up from the car's power).
- Connect the Dark wire on the headlight side connector to Ground.
- Now apply +12V to the headlight side connector's Light colored wire for a second or two. If you don't see or hear anything from that motor, then the motor is dead (possible broken wire internal to it). If it moves up then the problem is not in the motor, but more likely back at the control module.
The logic here is if you disconnect the headlight motor from the car and apply a direct +12V across the connector wires it should raise. The Control Module does just that except it keeps +12V on both wires and then switches the ground on the appropriate wire (hence applying +12V or -12V across the 2 wires) to raise or lower the headlight.
Last edited by JC in XTC5; Aug 16, 2006 at 04:30 PM.
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 844
Likes: 46
From: Southaven MS
OK. The headlight motor is fine. When I jumped it from the battery it worked perfectly. Does this mean the actuator control must be bad or is there a way to check it. The passenger side headlight works perfectly. wouldnt both lights not pop if the control was bad?
Drifting
Joined: May 2000
Posts: 1,917
Likes: 3
From: Southern NH
Originally Posted by redcycle13
OK. The headlight motor is fine. When I jumped it from the battery it worked perfectly. Does this mean the actuator control must be bad or is there a way to check it. The passenger side headlight works perfectly. wouldnt both lights not pop if the control was bad?
I've been thinging about how the control module knows when to switch it's internal relays on and off, i.e. how does it know when the headlight is raised and switch the ground relay back to +12V. I know it's not a timer since if the plastic stop on the headlight bracket is missing the motor will continue to run past the closed position and reopen as described in an old TSB on that issue. So it has to be some kind of sensing circuit that senses the increased current when the motor arm hits the stopper.
So to get back to the problem, this should help further isolate the problem:
- fashion a small test light with a small flashlight bulb and two wire leads.
- connect the test light leads to the light/dark motor wires at the output of the control module. It shouldn't matter whether you tap onto the wires with the motor still connected or not, but you may have to leave the motor connected due to the current sensing requirement of the control module. A way around this might be to measure the impedance of the motor and stick a similar value resistor in series with the test lamp so you can leave the motor disconnected.
- turn the headlight switch ON and you should see the test light illuminate during the time that the control module grounds the dark wire (and also when turning the switch off as it grounds the light wire).
If the test light does not turn on at the output of the control module, then that confirms where the problem is and you would need to replace it.
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 844
Likes: 46
From: Southaven MS
Another good idea. I'll check in the morning so i'll know for sure what to replace. Do you know if the control module is the same for firebirds. They look identical and can be found very cheap.
Drifting
Joined: May 2000
Posts: 1,917
Likes: 3
From: Southern NH
Originally Posted by redcycle13
Another good idea. I'll check in the morning so i'll know for sure what to replace. Do you know if the control module is the same for firebirds. They look identical and can be found very cheap.