Any ideas on why my motor is still running constantly? It runs anytime the headlight switch is up or down. Only when the parking lights are on does it shut off but then I can't have my main lights on. I ended up disconnecting the whole thing to keep from killing that motor.. On opening it up, I found the plastic gears are not stripped. Another note is that I cannot manually raise the headlight w/ the knob and this is a gen 1 on a 1985 GT.

Sure sounds like you have a stripped gear. Did you take the gears out and inspect them?

Have you looked at the small metal plate that captures the gear to drive it? It's pressed onto the shaft and if it comes loose, only has to move outward just a small amount in order to fail.


That plate has 4 tabs that insert into the gear cavities and hold the bump stops. Those fingers can also break off.



We commonly look at the large gear for indications of stripping,


But if you might have one of the early Generation 1 motors, it may have a second plastic gear that can strip.


And finally, if your motor has previously been rebuilt using plastic gears, it may have gotten aftermarket gears that were undersize, allowing only a small part of the edge of the teeth to engage. If the gear strips, it isn't as obvious as the picture above, and would require very close inspection of the very edges of the gear. Though some of those gears were white, many of the aftermarket gears were black.

There is another metal t-gear that can wear out when the motor won't stop. Mine (85 SE) would run whenever the headlights were on. I ignored it a long time until I got around to rebuilding, but it wasn't possible to rebuild and have a working unit because the t-gear was stripped. Finding a spare t-gear has been difficult. About the only way I see is to get a complete working unit. I ended up prying the unit up until it engaged the stop. I also had to cut a wire in the motor harness because the blue wire connector didn't stop it.

See I couldn't even find the slightest bit of wear on the gears (also there is only one plastic gear and a metal t-gear). I have a macbook so I can't post pictures but I'll see if I can get some up.

Possibly the armature has come loose from the steel shaft. I can't say I have seen that before in an 84-86 headlight motor but it happens in electric motors at times. The shaft is splined and it is a press fit into the armature. Generally that is a very tough connection and generally should never fail.

------------------
Rodney Dickman

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Had this problem with my 88 motor. The headlight would rise slightly but failed to go up all the way so I knew the motor was running. The adjustment knob failed to raise or lower the assembly. I ordered the rebuild kit but upon disassembly I found nothing amiss. Everything looked great. I found that with enough effort the metal shaft that passes through the large plastic gear would spin inside the gear. The motor would run but with the shaft spinning inside the gear the headlight would not come up.

I received some advice here to drill through the gear and the shaft and insert a roll pin to lock them together. I did a variation on this method by drilling an angled slot on both sides of the shaft where it enters the gear body and inserted wedges to lock the shaft to it. Then reinstalled the 3 plastic pins and then seated the actual gear. Not elegant, but I don't have a drill press and lacked the confidence to drill it by hand precisely enough for the pin to seat securely. I shoulda taken a few pics but you get the idea. This was a couple of months ago but it seems to be working great.


I know the gen 1 motors are different but I thought this could be useful.

[This message has been edited by Rsvl-Rider (edited 01-10-2015).]

quote Originally posted by Rsvl-Rider: ...................... I know the gen 1 motors are different but I thought this could be useful.

Yes, that procedure might be a little difficult with the Generation 1 motors. The gear actually spins freely on the shaft until the drive plate that captures the bump stops is attached to the shaft. The gear actually turns the plate which in turn rotates the shaft. The only way I can see that the Gen. 1 motor could run without without lifting the motor is either a gear is stripped, which he says it isn't, or the windings have come loose from the main screw shaft of the motor, or the drive plate has lost it's fingers or come loose from the horizontal shaft.