Headlights, Left Opens But Won't Close Automatically!

[ParisTNDude]

My driver's side headlight wasn't opening and I had been driving with both open using the manual operation mode. I thought the headlight motor had gone bonkers, but found out (after removing it and testing it) that the motor is in great shape. When I put it back in the car, I was amazed that the headlight door on the driver's side closed automatically, but still wouldn't open. The right works perfectly. I searched everywhere and found what I think is the problem...one of the 3 relays is probably bad...which one, I don't know. I am waiting for my factory service manual to arrive and maybe it will give the troubleshooting information I need. Does anyone have experience at fixing this winking headlight dilema???

 

[wildbill85]

1984-87 Corvettes have three relays that control the operation of the headlight doors

Suggested Installation Instructions for Product Numbers:
618-649 1984-1987 Corvette Headlight Actuator Isolation Relay
601-723 1984-1987 Corvette Headlight Door Actuator Relay
The 1984-87 Corvettes have three relays that control the operation of the headlight doors. One
isolation relay (618-649) and two for the headlight door actuators (601-723). All three should be
replaced at the same time.
The relays are located in the left front bumper area and are mounted on the inner wheel housing.
DIRECTIONS FOR SAFE AND PROPER APPLICATION
Procedure:
Step 1: To access the relays remove the two 7 mm screws holding the plastic cover over the relays.
Step 2: Remove the two 10 mm screws holding the bracket assembly to the inner wheel housing.
Step 3: To remove the relays, lift up the long metal plate lock that holds the relay to the bracket.
The relay will then slide off the bracket.
Step 4: Install the new relay and reassemble components by reversing Steps 1-3.
Front
of
Car
Isolation Relay
And Connector
Headlight Door
Relay &
Connectors
LH FRONT OF ENGINE COMPARTMENT ON
WHEELHOUSE HEADLIGHT PANEL

 

[ParisTNDude]

Thanks

Thanks for the info. Do you happen to know which of the three relays operates the driver's side headlight? I'm guessing one of the three relays is bad, but I don't want to replace all three if they're good. After reading your notes again, it looks like both doors use the same part number for the left and right relay...is that right?

 

[wildbill85]

I had the same problem with the left headlight,when i would close the light it would not shut off burned up 1 gear, not knowing what was wrong. I rebuilt that headlight motor it worked for about a 1/2 hour burned up that gear. So I purchased a new motor installed it.,work for about a week and it did the same thing. I thought I burned that gear up.I took it a part on Sunday I found that the motor was ok,what i found was that the pigtail that you connect the motor two was getting a bad connection. There is 3 prongs on the plug if you look at it you can see if they are line up right or if they are pushed back. One pin is for the open and the other pin on the plug is for the closed on the headlight. I did this on my 85 vette and it seems ok now This might be your problem a bad connection on your plug not the relays. Bill

 

[ParisTNDude]

You've got a good idea

Good idea! I'm going to check that out today. Thanks, again!

 

[boomdriver]

Good idea! I'm going to check that out today. Thanks, again!

why not just trade the relays and see if the problem moves?

if it does not move, then it gets complicated. The motors shut off/stop signal comes from internal limit switches that work from the shaft torque as it hits the end of travel. It pulls the shaft one way or the other. There are sets of breaker points that open or close to turn off the motor. The relay then changes the direction based on what path the breaker points have allowed. These are just like the points in an old ignition system. They get worn and do not make contact or they get burned. They have to be adjusted properly. The motor shaft also has a spring that helps it maintain center. This is usually where everyone screws up not getting that installed properly. If you;re willing to do surgery on a delicate motor (you'll need to learn to do gears soon) you can do this in a couple hrs if you really pay attention to the mechanism. Or you can do an exchange for $150 each...or upgrade to 89 & up motors that do not use relays and breakers but have their own issues with a drive system thats designed to wear...