Velkinheim

Hey guys, been lurking on this site for a while, never really needed to make a new thread before, until now.

I have a 1986 C4 Corvette, and my headlight motors failed on me in the open position, and I'm getting really tired of manually closing them during the day. I found that they still automatically open up just fine, it's just they get stuck open and won't automatically close when I push in my headlight switch in.

Before the motor outright failed on me, they were just kind of delayed at first. As in, when I hit the switch to turn them off, the passenger side didn't close right away, but rather took anywhere between 10-30 seconds to automatically close.

I thought it was due to the cold weather and snow, and thought I should just change to the bronze gears later in spring.

2 weeks later, the same thing starts to happen to my drivers side. They would close at the same exact time, it's just that both of them started taking anywhere between 1-30 seconds to automatically shut off. (I noticed that they tend to close faster when it was warmer outside)

Then a day later, next thing I know, they just never closed automatically ever again.

I went through this site combing all the headlight motor related threads I could find, I disconnected my head light assembly, opened the motors up and found that the plastic gears are in perfectly fine working condition. The 4 rubber stoppers in the plastic gears are also in perfectly fine working condition. Everything was greased up, and sealed with silicon when I first opened it.

I read from other threads that sometimes problems occur with the limit switches, maybe the contacts were not good, but when I hooked up the motor to an external power source, the motor worked as it should, operating perfectly fine in both directions. (as in, they would totally open and close the headlight assembly if they were hooked up)

So now I'm starting to think that there's something wrong with my relays. I know there are two actuator relays, and one isolation relay, and I replaced all 3.

After replacing the old relays, I greased, sealed, screwed, bolted and hooked everything back up. I pulled my headlight switch, and the headlights opened normally just like I was able to before this problem, but when I pushed the headlight switch in to turn off the lights and close the headlights...nothing. She just refuses to flip back shut.

I'll leave a wiring diagram here so you guys can follow me :


I took a multi meter and tested the terminal that comes from the relays. It's supposed clip onto the cable that's hooked up to the actual headlight motor. There's three lines in that one bundle, black, white and green.

With my headlight switch in the off position (as in, the position that's supposed to turn/flip the headlights closed) green always reads 12v, white reads relatively nothing, and black is my ground.

I connected the motor assembly directly to my car battery terminals and found that the motor will spin, in both directions just like I did with my external power source. (I just have to flip the alligator switches I have to make the motort run the other direction. + to green, - to ground to spin the motors one way, - to green + to ground to spin the motor the other way.)

So, just today, I thought that maybe the terminals weren't making good contact, so I bridged the female terminals from the relays to the male terminals in my headlight motors with my alligator clips...and nothing.

I did find something odd. When I bridged the motors to the relays/rest of the car, it just drops power. The 12 volts from my relays/car just drops down to 0 when she's hooked up to the headlight motor.

So now I'm completely stumped as to what could be causing the problem. My gears are good, the rubber stoppers are fine, I THINK my limit switches are just fine too, the motor spins in both directions, new actuator relays, new isolation relay. The cables between headlight motor and relays make good contact...It's just when they do contact...it just mysteriously drops power.

I'll link a few pictures of my limit switches, cause the limit switches are the only things I am not 100% positive about. I kept reading from other threads that the shaft is supposed to move these contacts points (the limit switches) and break the circuit, but nothing moves. My contacts always seem to be touching, and my shaft only rotates. It doesn't move in any other direction Can someone enlighten me about the limit switches and the shaft in greater detail?

https://imgur.com/a/nIfcb?

Here are the two other threads that I thought were the biggest help in troubleshooting my headlight motors thus far.

https://www.corvetteforum.com/forums...placement.html

https://www.corvetteforum.com/forums...ght-motor.html


I currently have the left hand driver's side motor dissected and I can take plenty of pictures, so just ask.

UPDATE 3/28/18

I figured out how the shaft of the headlight motor is supposed to break contact on ONE of the limit switches. I just had to really push down hard on the grey manual turn ****.

I assembled the driver's side headlight motor, and attached it back to the hood, and this time when I pull headlight switch, the driver's side automatically closed (when it should have opened) and the passenger's side flipped open. But when I pushed the headlight switch in to turn everything off, nothing happened. They didn't reverse at all. I'm getting really frustrated with this thing.

xrav22

Something I noticed when I put my new headlight **** on. Make sure that yout **** isnt all the way down on the rod because it will stop before your switch closes all the way.
Sounds silly I agree but I was wondering why my lights did not close just after replacing ****.
Clean all contacts with cleaner, good luck

Ukguy1986

Velkinheim

To whomever it may concern, I found out what the problem was. My 12v line is bad. I made a direct connection from the positive end of my battery terminal all the way to the 12v line. (idk why it took me this long to do that, this whole time I kept thinking I was having a bad ground) On the left hand side, it's the green line, on the right hand side, it's the green and white line. When both those wires are bypassed, and a direct connection from the positive battery terminal is made, the headlights will automatically close.

That wire is supposed to be "hot at all times". I get a 12v reading when I disconnect the clips that give power to the motor, but as I've discovered a while ago, when connected, the power just mysteriously drops under load.

The solution to my odd problem is that I just need to replace the "hot at all times" wire on both sides.

Tho, my new problem is that I don't know where this line is actually broken. I don't know if it broke between the motors and the relays, or from the relays to the headlight switch itself.

Velkinheim

Hearing you say that almost confirms my suspicions.

I'm almost positive it isn't the fuse link, because when I hook my multi meter to it, I get a voltage reading of 12. It just so happens, under any kind of load, that power drops.

I'm almost 100% positive that the problem lies somewhere with my red wire, the "hot at all times" wire in the diagram. My problem now is I just don't know where exactly the break is.

From what I described in my post, how initially it was just the passenger side, then eventually the driver's side became affected, I'm inclined to believe that the entire wire has corroded/broken/crimped or whatever, and will need to be replaced. From headlight switch all the way to both motors.

Velkinheim

I know I'm super late to this, but turns out the problem was the switch itself. There was a fault in the wiring right behind the actually switch that on the dash.