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Early C4 Headlamp help needed! New Problem!

OSU-VETTE

Well-known member
Joined
Jan 19, 2003
Messages
60
Location
Central OH
Corvette
1985 Z51, Black with Purple Accents
Hello everyone,

I have searched through all the forums for advice and guidance on my headlamp problem, I am reasonably sure it is the gears, but not completely. The passenger side light would "stick" in the upright position and eventually drop down, especially when I would drop the hood. Now it is stuck down, moves about 1 inch to flip up and no further. Shuts fine. The manual release takes it no further than the inch the motor takes it. I don't hear the motor running when trying to go past the 1 inch, however it may be and I cannot hear it over my cursing.

Before I spend the hours on the gear change, I would greatly appreciate any guidance from this community, I may go the rebuild route through Ecklers ($129 plus core) if I must. Kind of leaning that way anyway, not sure the many hours to do the rebuild is worth it if I don't know for sure this will fix it! Thanks in advance to any and all help.

Oh, and Go Bucks!

Jeff
 

Jeb

Well-known member
Joined
Jan 20, 2005
Messages
456
Location
Covington, Louisiana
Corvette
1987 Convertable
You might try placing your hand on the headlight motor while an assistant flips the switch so that you can "feel" whether the motor is working. I'm hard of hearing myself so I have to do this sort of thing quite often.

I haven't had to rebuild mine (yet) but I understand that a reasonably competent shadetree mechanic can do the rebuilding without too much of a problem and you'll save some of those BUCKS! There are some great articles here on how to do it.

GO BUCKEYES!!!

Muck Fishigan!
 

milehigreg

Well-known member
Joined
Dec 3, 2004
Messages
271
Location
Denver Colorado
Corvette
1989 Dark Red Coupe
Go for It!

Changing the plastic bushings is not difficult and it is inexpensive. There are articles on the forum and the latest Corvette Magazine has a new article on this standard DIY fix. Everybody does it. Jump off the bridge.:_rock
 

OSU-VETTE

Well-known member
Joined
Jan 19, 2003
Messages
60
Location
Central OH
Corvette
1985 Z51, Black with Purple Accents
Thanks, I have reviewed all the articles, it doesn't look that difficult, just taking my time, I will probably order the gears and give it a shot, worse case I order the rebuilt motor, nothing ventured, nothing gained.
 

GuyzVette

Well-known member
Joined
Dec 19, 2005
Messages
86
Location
Wichita, KS
Corvette
Polo Green 1994 LT-1
Yeah, I was worried about doing it, as I am a big time novice as far as mechanics go. But I did both of mine, and then did a buddy of mine's car a few weeks later. The picture instructions really help the first time you do it, but it's much easier on the second one. Plus, its such a cheap option, and then when you are done, you know you don't have to worry about it for at least another 10 years.
 

OSU-VETTE

Well-known member
Joined
Jan 19, 2003
Messages
60
Location
Central OH
Corvette
1985 Z51, Black with Purple Accents
Thanks everyone for all your encouragement and experience, I am hoping the true root cause is the gears and not something else, will let you know what I find. I ordered the gears today from Ecklers, they are usually very quick at shipping and I have Saturday ready to go since the Bucks don't play until 8pm.

Thanks again!
 
Joined
Sep 16, 2003
Messages
522
Location
Newark, OH
Corvette
2003 50th Anniversary Convertible
Let us know how everything goes! Good luck!!

GO BUCKS!!

Jim
 

MrRenoman

Member
Joined
Sep 28, 2006
Messages
7
Location
Sparks, NV
Corvette
1998 Convertible 6 spd, Pewter/Black
Keep in mind that the early C4s 84-87 have an entirely different style motor than the later C4s. Early C4 motors don't use bushings in them. Both style motors do fail over time but for different reasons. Usually both style motors, when they do fail, exhibit similar problems. They stop rotating or are intermittent. Early C4 motor failures are frequently caused by dirty limit switch contacts or brushes. These are the 3-wire motors that use relays to direct current through the motors. The motor internal limit switch operate under torque when the motors operate the headlight assemblies. When an early motor turns a headlight assembly the assembly completely rotates and hits stop which exerts torque on the motor. This torque is transferred into a linear motion which causes internal contacts to open and close. It is these contacts, when dirty, that cause the motor to stop it's rotation. Frequently a push on the headlight assembly or a rotation of the knob on the end of the motor will cause the headlight assembly to continue to rotate. If the motor is intermittent but does rotate both headlights intermittently then a cleaning of the internals usually restores the motors to good health and usually with no additional parts.

Later C4 motors use a 2-wire motor connected to a controller that reverses the current through the motor causing the motor to rotate in opposite directions. Frequently, the internal bushings deteriorate and turn to dust. When this happens the motors will only turn the motors parts way, may continue running but nothing is happening. Dismantling the motors and replacing the bushings is usually all that is required to restore these motors.

There are other things that could be contributing to poor headlight operations including failed relays and or high resistance connections in the contacts. So a thorough inspection and isolation of the problem is required. The factory service manual (FSM) is a valuable tool to do this.

There are troubleshooting procedures in the FSM to determine if the problem with the early C4 motors are with the relays, wiring or the motors themselves. It's a good place to start before tearing things apart.

Frequently replies to posts such as headlight problems recommend the wrong solution simply because some authors may not realize the differences in the motors. It happens in many posts I read about headlight motor problems. If you have an early motor then isolating the current through the relays to the motors and cleaning the limit switches and brushes is the easiest and cheapest way to attack the problem. Later C4 usually require just bushings, but I've also read that some motors, both early and late, will need gears. Gears aren't as common a failure as are dirty contacts or bushings.

Art
 

OSU-VETTE

Well-known member
Joined
Jan 19, 2003
Messages
60
Location
Central OH
Corvette
1985 Z51, Black with Purple Accents
Art, thanks for the thorough response, my current problem is the headlight goes up about 2 inches, very quickly, then stops like it is binding or hitting something. The manual knob will not let it go any further. I have the gears to rip it apart and try to fix it, I am leaning toward a tooth on a gear went bad and it is binding on that. I do have an early C4 (85) so if this doesn't fix it, will try cleaning the connections as you suggest. Heck, I am sure I will clean them anyway since I will have it all apart. Appreciate the advice, the goal is to attack it today while it is raining. Will update everyone when I find the problem, hopefully the fix!
 

MrRenoman

Member
Joined
Sep 28, 2006
Messages
7
Location
Sparks, NV
Corvette
1998 Convertible 6 spd, Pewter/Black
It's very possible it's a gear. I have seen a few that have broken gears. If the headlight rotation is stopping and you can't turn it, that seems more like a mechanical problem. Also, I've seen where the side headlight cover screw has backed out hitting the hood during rotation causing the assembly to stop in it's tracks. If that's not the problem then it does seem like gears. Good luck.

Art
 

OSU-VETTE

Well-known member
Joined
Jan 19, 2003
Messages
60
Location
Central OH
Corvette
1985 Z51, Black with Purple Accents
I finally got around to taking apart the motor yesterday and decided to take a much closer look at the problem. Once again it seemed like the headlamp was catching on something, and sure enough, it was. The screw that holds the cover in had worked its way out and was hitting the hood. Unfortunately the headlamp motor is very strong and as I put a little (and I mean very little) pressure on the unit, it pushed around and tore a piece of the hood off about an inch long and 1/4 side. Looks just lovely now.

I was so disgusted with myself I did not change the gears, will tackle that over the winter at this point. So, lesson learned, look for the little things and take your time. Now I get to visit a body shop to see about getting this fixed. At least the Buckeyes stomped Iowa.

Thanks everyone for all your support and help, I will keep you updated on when I do get around to fixing it!
 

MrRenoman

Member
Joined
Sep 28, 2006
Messages
7
Location
Sparks, NV
Corvette
1998 Convertible 6 spd, Pewter/Black
That's a real bummer. I had the exact same thing happen to me. The headlight wouldn't rotate very far. That's when I realized that the screwed had backed out and was hitting the hood. The lesson learned from this was why I mentioned it in my previous post in this thread. Sorry to hear it tore up the hood, it did nick mine too. I know this is enough to p*$$ anybody off. I'm sure you had a few choice words and thoughts when it happened, I did.

Art
 

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