I am trying to get the headlight doors to function on my 73 Dodge Monaco. I have a few motors & extra relays. I figured a 73 Chrysler 300 motor & relay would be the same however the motor didn't work. I bought a 69 Imperial motor (for $150) & it wouldn't take the headlight bar so I switched the white plastic parts from the 73 Monaco to the Imperial: the motor works but doesn't open the doors. Must they be adjusted somehow? I switched the relays as well: 73 300 to 73 Monaco. I have one working motor: the 69 Imperial & I am starting to think the relay wasn't bad on the car to begin with so I can put that back. I don't think I put the white part in the motor correctly. Any advice on what to do next? Can I fix mine? I would pay for a good 73 Monaco motor or trade.
You can get yours rebuilt at
www.headlightmotorman.com
A couple of tests to run first. Put the plastic parts back in your original motor, be careful not to damage the switch plates. Once re-assembled, ground the motor to a good ground. There is a two wire connector going into the motor. One wire moves the motor to open the headlight doors, the other moves the motor in the opposite direction to close the headlight doors. Use the manual knob to turn the motor one direction or the other until it locks up. If the motor will not lock up, most likely your white gear set is stripped out. If you are able to get the motor to lock up, briefly touch a hot lead to one of the two leads going into the motor. This will prevent the motor from breaking the gear set because the gear set has no load on it. One lead will do nothing, the other lead should move the motor and the square gear hub. If that works, keep briefly touching the working lead until the motor locks up. Now reverse the process with the other wire that previously did nothing. It should now move the motor in the opposite direction. If the motor will run in one direction but not the other, the switch plate is bad. If the motor will run and lock in both directions, it should open and close the headlight doors.
To test the relay function, use a test light. Ground the test light and prepare to hook the probe to the detached harness that feeds the motor. Turn on the vehicle ignition and the light switch. One wire from the two wire harness should light the test light. If that happens, turn off the headlight switch with the ignition still on and the other lead should now light the test light. If neither wire will light the test light, the relay is bad. If only one wire lights the test light, the relay is also bad. Rarely, a bad light switch will keep power from getting to the relay. Run these tests and report back.
Most of these motors were pretty much the same in terms of the internal function. I memory serves me correctly, I think some of the latter ones had a different sized operating rod for the headlight doors, which would explain why the rod would not fit you purchased motor, but I am not sure about that.
Dave