Headlight mystery C4

[Vette1993]

Strange problem. My 85 coupe started having this headlight problem a short time ago. When headlight switch is turned on, the two lamps start to rotate to the open position, however the right lamp stops halfway open. There is no grinding sound, no thump, clicking or otherwise. Lamp is on, just entire bucket is not fully open. Same thing upon closing switch. However, if the switch is pulled while hood is fully opened, all works perfectly. I have checked for obstructions within the headlamp area, found nothing. Lamp also retracts perfectly to closed position while the hood is open. Something is failing halfway through the rotation. I have checked, cleaned and lubricated all moving joints visible on the assembly. Any ideas???

 

[AlbertaZ06]

just had this problem last year. Ended up being not the gears in the headlight motor, but the plastic dowel pins inside the gears. I ordered some cheap dorman ones off amazon for a Ford that worked. Think I have pictures of the rebuild on my LSX Swap post somewhere in it. I even cut up some rubber hose and put in there to keep me going, until I found parts that would work, and wasn't a expensive complete rebuild kit.

 

[2KforeverC5]

Strange problem. My 85 coupe started having this headlight problem a short time ago. When headlight switch is turned on, the two lamps start to rotate to the open position, however the right lamp stops halfway open. There is no grinding sound, no thump, clicking or otherwise. Lamp is on, just entire bucket is not fully open. Same thing upon closing switch. However, if the switch is pulled while hood is fully opened, all works perfectly. I have checked for obstructions within the headlamp area, found nothing. Lamp also retracts perfectly to closed position while the hood is open. Something is failing halfway through the rotation. I have checked, cleaned and lubricated all moving joints visible on the assembly. Any ideas???

Head lights both working? High and low beams? Remove pop up fuse Manually open the pop ups gently feeling for a miss while turning. It should go all the way up manually. Close it back manually gently feeling for a miss. Replace fuse back you’ll hear a current click (normal). Engine off. Turn on headlights as if you’re replacing the bulbs. Both pop ups should be open. Everything should be back to normal.

 

[Dave91TM]

Mine went wonky a few years back. When turned on or off the lights rotated but the motors tried to keep going and made a whirr thunk whirr thunk noise. Turned out to be the delrin bushings, a cheap fix. Yours seem too quiet for the bushing problem, I'd try 2k's
suggestion first.

 

[Vette1993]

Yay!!! Problem solved! Working with my son, we discovered that the jam occurs when the hood is lowered to almost being closed, so it was an interference problem. After feeling around the lamp assembly, we discovered that the edge of the c-clamp that holds the rubber overflow tube was binding against the edge of the lamp assembly. Fix was to relocate the bracket to the left overflow tank mounting screw, and I also rerouted the hose under the A/C lines back up to the radiator. All is good now.