70 Charger headlight doors will only go down using light switch

[matchek]

Hi need help with someone who has deep understanding of electrical wiring and grounding.  A couple of years ago a mechanic replaced the headlight relay with a modern one.   The headlight doors worked for a year and then stopped working.  Got busy and forgot about it.  Now it bugs me as the the doors look cool closed but want to be able to drive at night. Can't open them with the light switch.

So I did a lot of research on the 5 pin headlight/headlight door relay.  I since replaced it with 2 different relays and did not change the problem.   I tested the relays on a bench and they work as they should.

I have a weird unique voltage issue.  First though if I connect a wire to from the battery, the motor opens and closes the doors perfectly.

When I turn on the lights, with car running, the doors stay closed.   The wire to the motor to open the motor reads 10.5 V and the wire to close it reads 7 V (it is supposed to read 12.5V and 0 V).  That is really weird so the motor is getting current to open the door and close the door?!?!

With the light switch on, if I gently pull up both doors with my hand around 1 inch,  I hear 2 to 4 clicks and the doors open the rest of the way on their own.   With the doors fully open, the voltage to open the doors read 12.5 V and the close the doors wiring reads 0 V as it should. 

Another thing with wiring two prong disconnected at the motor, with the light switch on and the engine running the wire to supply current to open the doors read 12.5 V and to close reads 0V as it should.  It is only after everything is plugged in right with the engine running that the I have what appears opposing current at the motor. Really weird.  So frustrated. Does anyone have any ideas???

Also when the doors are open, the doors always close when I turn the light switch off. 



 

[70 sublime]

Sounds like the switch in the motor is not right if you unplug the wires and have normal voltage that you would expect

There is a plastic gear in the drive of the electric motor that has stops on it to turn the two power switches off and on when it is fully open or fully closed

You can get a new plastic gear but be careful when you open it up because it can be very fiddley to get it all back together again

Sounds like some of the teeth are broken off because you can open the doors part way by hand then it takes over and does what it is supposed to do