I was asked to consult on a buddy's 1970 Charger equipped with hidden headlights. Customer complaint was a large unexplained draw with ignition on. I traced this to a 6-7 amp draw from the motor that moves the headlight doors. Although the gross function of the system is apparently okay (headlight doors go up and down when they should), the motor 'down' circuit is still pulling a load even after the doors are all the way down. Clearly, the internal limit switch is not doing its job.
My buddy's "service manual" is woefully inadequate when it comes to the internal workings of the system. (Although a genuine Mopar book, I don't think it's the full FSM.) It does cover how to diagnose and repair a non-working system, provides warnings about running the motor without a load and turning the knob without disconnecting the harness - but not much else.
This motor was supposedly rebuilt during the tenure of a previous owner, but that sentence now tells you about as much as I know about that rebuild.
Are there any user serviceable or adjustable characteristics of this system short of a motor teardown? I welcome any comments in general, or specific answers to the following two possibilities:
a. There is a small slotted screw at the top of the "differential housing" on top of the motor. Is that of any help here?
b. There is an adjustment at each side so the doors can be allowed to close "further". Even so, if using said adjustment would allow the motor to travel to the limit switch, it would leave the doors horribly out of alignment with the surrounding grille. When I look at the system, the shade-tree side of me wants to "clock" the motor differently on its mount. If I trashed the paint and detailing in this area, would there be much movement to be had?
If the down limit switch is trash, of course the motor needs to come apart. If the switch isn't trash, there has to something to tweak here.
Sorry for the long read. Thank you in advance for any suggestions.