Headlight question on '85 (help)
Thread Starter
Heel & Toe
Joined: Mar 2005
Posts: 18
Likes: 0
Headlight question on '85 (help)
On my '85, the driver side headlight will not open when I pull the switch, but when I manually open it, it will close using the motor. Is the something which can be fixed, or will I need a new motor.
Team Owner
Joined: Jan 2003
Posts: 20,306
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From: Summerland B.C. Canada
Thread Starter
Heel & Toe
Joined: Mar 2005
Posts: 18
Likes: 0
Thanks for the PDF Agent86 hopefully this will help. Forgot to mention that I took the motor apart and the gears are fine, had new ones ready to replace the old ones and to my surprise they looked brand new. The motor has to work since in turns the lights back to the closed position.
Pro
Joined: Jul 2002
Posts: 729
Likes: 4
From: Yukon OK
There are 3 relays in the group. Two of them can be swapped the third cannot. It is called the isolation relay.
The early C4 motors have two limit switches internal to the motor to stop the motor when the headlight hits the stop going up or down. It uses the worm gear acting against a spring to push a drive dog and activate the proper limit switch.
Now on to the problem. When the contacts on the switches go bad you will lose the motor in ONE direction but not the other. It is possible to clean the switches by taking the motor apart and removing the rotor. It is a real pain and the fix is only temporary.
You could also have a problem with the head light switch. Best bet is to measure the voltage at the motor. There are three wires; a ground, an Up wire and a Down wire. The up and down have 12 volts when the motor is to travel in each direction. I had a motor that would work if I hit it on the side with a screwdriver handle when voltage was applied. It jarred the contacts just enough to make contact.
Best bet is to watch eBay and buy a set of 88 and later headlight assemblies and then buy the control module and eliminate the relays. The later headlights are much more reliable, but you do have to be sure the delron bushings are good.
Good luck
The early C4 motors have two limit switches internal to the motor to stop the motor when the headlight hits the stop going up or down. It uses the worm gear acting against a spring to push a drive dog and activate the proper limit switch.
Now on to the problem. When the contacts on the switches go bad you will lose the motor in ONE direction but not the other. It is possible to clean the switches by taking the motor apart and removing the rotor. It is a real pain and the fix is only temporary.
You could also have a problem with the head light switch. Best bet is to measure the voltage at the motor. There are three wires; a ground, an Up wire and a Down wire. The up and down have 12 volts when the motor is to travel in each direction. I had a motor that would work if I hit it on the side with a screwdriver handle when voltage was applied. It jarred the contacts just enough to make contact.
Best bet is to watch eBay and buy a set of 88 and later headlight assemblies and then buy the control module and eliminate the relays. The later headlights are much more reliable, but you do have to be sure the delron bushings are good.
Good luck
