jja Posted January 8, 2012 Share Posted January 8, 2012 My 70 MC came with the power door lock option. However, the locks do not open/close using the switch on the driver's side. They both open/close using the switch from the passengers side. Because the solenoids both work but only from the passenger's side, I am assuming the drivers side switch is bad. I took the switch off to bench test it with an tester that has the black and red leads and that you can test ohms, volts, etc. The back of the switch has two prongs that I connected the back and red leads to and then pressed the switch to see if the needle moved. It did not. Attaching the leads to the wire from the doors shows current (the needle moved). Can the switch be bad? Any use in taking the switch apart and trying to clean/repair it? Am I on the right track? Quote Link to comment Share on other sites More sharing options...
cny first gen 71 Posted January 8, 2012 Share Posted January 8, 2012 Check the wires that go throught the door too 40+ years of flexing they can break. Quote Link to comment Share on other sites More sharing options...
Mr70Monte Posted January 8, 2012 Share Posted January 8, 2012 there should be 3 terminals on the back of the switch. kinda like this ( lock) o o (common) (unlock) o using your meter (analog or digital) on the lowest ohms setting, black wire to common, red wire to lock.......move switch on front, meter should move.... then move the red wire to the unlock terminal......do the same with the switch......meter should move I've disassembled the switches before, but never had any luck with getting them to stay back together, new switches for '70 are now available. hope this helps. Quote Link to comment Share on other sites More sharing options...
overdrive Posted January 8, 2012 Share Posted January 8, 2012 The first thing I'd check is connect the wires back on the switch and make sure you have 12 volts at the switch. It can't send voltage to the actuator if there's none at the switch. Set the volt/ohmmeter to DC voltage and put the black lead on a good, clean ground somewhere on the door. Use the red lead on a fuse that's powered with the key off,(just test them all if you don't know which one)to prove that you actually have a good ground. Some fuses are powered with the key off and some only when it's on. With the red lead on a 12v source, if you can't get power and your black lead has a good connection on the door, the door isn't grounded. This isn't likely, but it could be possible. Once you're sure you have a good ground connection with the black lead, test with the red lead to see if one of the 3 wires on the switch has 12vDC. If you have no voltage, you must go backwards from there to find where the power is lost. If you have 12vDC, now operate the switch and see if you have voltage on one of the other wires. Check the third wire for the other switch position. I took my switches apart and had the bezels replated. They can be disassembled and put back together. On all but one I was able to bend a small part of the bezel over the edge of the contact plate, like it was done at the factory. I used a very small drill bit and was able to drill the bezel and put a "pin" across the back side to hold it together on one of either the window or lock switches. Good luck and let us know if you need more help. Somebody here will help you out. Dan Quote Link to comment Share on other sites More sharing options...
jja Posted January 9, 2012 Author Share Posted January 9, 2012 The contacts between the switch and the wire plug just needed a little filing. Thanks for all your help. I especially like the replies that get all technical. Quote Link to comment Share on other sites More sharing options...
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