85 Vette Headlight Won't Open
Thread Starter
Cruising
Joined: Sep 2012
Posts: 12
Likes: 2
From: Noblesville, IN
85 Vette Headlight Won't Open
New to the vette owners club. Got an 85 with headlight frustrations. Rebuilt right side with new gears, new/used left. New relays. Hand crank them up and they will close but they refuse to open. Any clues? Thanks
Last edited by chief85vette; Jan 8, 2013 at 08:51 PM.
Thread Starter
Cruising
Joined: Sep 2012
Posts: 12
Likes: 2
From: Noblesville, IN
Thanks for the post Razor. I got the left to work except when you go from head to park it does not close. Hmmm.
Now right side will close but not open. Fuseable links check good. No power at RH relay. The trouble shooting guide I found said to check the isolation relay. From what I can tell the headlight switch might be bad. I get battery voltage on the gray wire at all times (off/head).
Your thoughts?
Now right side will close but not open. Fuseable links check good. No power at RH relay. The trouble shooting guide I found said to check the isolation relay. From what I can tell the headlight switch might be bad. I get battery voltage on the gray wire at all times (off/head).
Your thoughts?
Race Director
Joined: Aug 2007
Posts: 11,889
Likes: 8
From: Whitefish Falls Ontario
St. Jude Donor '08-'09
Pull the two relays for the motors and check their terminals, if ok try switching them when you put them back, you should have power to the right hand relay directly from fusible link "G" through its contacts to the dk/grn and ground through the relay to the white to operate the motor..
Last edited by ccrazor; Jan 10, 2013 at 10:47 PM.
Thread Starter
Cruising
Joined: Sep 2012
Posts: 12
Likes: 2
From: Noblesville, IN
I will try that this weekend. When I started, the RH motor worked up/down. LH would not move. Now LH goes up/down, RH does not move.
I hear the isolation relay clicking when I move it around. Hmmm.
You have been a big help!
I hear the isolation relay clicking when I move it around. Hmmm.
You have been a big help!
Race Director
Joined: Aug 2007
Posts: 11,889
Likes: 8
From: Whitefish Falls Ontario
St. Jude Donor '08-'09
The isolation relay is used only in the close operation.. It operates when the lights are turned on.. With the switch off the normally closed contacts are used to supply power to the right hand motor, the left motor gets power on the grey wire from the light switch to close the lights.. With the switch off, both motors have power to the grey wire.. 
Last edited by ccrazor; Jan 11, 2013 at 10:25 PM.
Thread Starter
Cruising
Joined: Sep 2012
Posts: 12
Likes: 2
From: Noblesville, IN
Ok. I traced the fuseable links from the each fuse to the relays and found a bad spot in one wire. Tried to load pics but have not got that far. Wire was not kinked or spliced just a noticable fat spot cut it open and complete corosion. Repaiered now itiis good to go.
Now I have voltage and both relays. LH works fine. RH has voltage on GRN/WHT to the motor but won't go up. Suspect motor went bad after I rebuilt gears. It worked about three times after gear replacement then nothing. Still goes down just not up.
Is there a way to rebuild it or is it better to replace it?
Now I have voltage and both relays. LH works fine. RH has voltage on GRN/WHT to the motor but won't go up. Suspect motor went bad after I rebuilt gears. It worked about three times after gear replacement then nothing. Still goes down just not up.
Is there a way to rebuild it or is it better to replace it?
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Race Director
Joined: Aug 2007
Posts: 11,889
Likes: 8
From: Whitefish Falls Ontario
St. Jude Donor '08-'09
If it goes one way it should go the other, are you getting a ground on white when you have power on the green?? If not check the ground connection behind the RH headlight..
Thread Starter
Cruising
Joined: Sep 2012
Posts: 12
Likes: 2
From: Noblesville, IN
Checked and cleaned the ground. RH works when it wants to. Turn on and it sits there then opens. Sometimes part way sometimes all the way. Closer than where we were at the start. Going to check continuity to ground. Maybe a bad spot in the wire there too.
Safety Car
Joined: Sep 2004
Posts: 3,953
Likes: 550
From: Mission Viejo CA
It sounds to me like you have dirty limit swithes inside your headlight motors. Since you replaced the gears in one motor, I'm presuming you figured out how these limit switches work. The motor armature must slide on its axis to actuate the switches. Use a lightweight white grease (Lubriplate or equiv.) on the motor bearings.
If the motor goes one way but not the other, your motor is good. Yes, going from headlights to parking lights, the lights stay up.
I was having the same problems, but now my headlight doors could tear your arm off!
If the motor goes one way but not the other, your motor is good. Yes, going from headlights to parking lights, the lights stay up.
I was having the same problems, but now my headlight doors could tear your arm off!
Last edited by Hot Rod Roy; Jan 22, 2013 at 01:01 AM.
Race Director
Joined: Aug 2007
Posts: 11,889
Likes: 8
From: Whitefish Falls Ontario
St. Jude Donor '08-'09
With the hood open, have someone operate the light switch, do you hear, or can you feel the motor running?? If not you need to check the green for ground and the white for power.. What is the condition of the connectors?? If the motor is running that would indicate a problem with the gears, I know you said you changed the right hand one, but if it's running it should open. If it doesn't run and you have power (assuming it closes properly all the time,) then you need to open the motor up and check the two sets of n/c (normally closed) contacts under the commutator..
Thread Starter
Cruising
Joined: Sep 2012
Posts: 12
Likes: 2
From: Noblesville, IN
Hey long time no hear from me. All good advice. I still need to check the headlight motor because I think the limit switches are the problem. When I plug it in I hear popping and clicking in the closed. I pull the light switch and walk around then it opens. When it is in the open there is no sound. Will check it out this weekend. Thanks Dave