back up lights

The back up lights on my 1971 Comet GT do not work. Fuse is OK, bulbs also OK. Am I correct in assuming that the back up light switch on the floor shifted C4 is also part of the neutral safety switch? I tried moving the shift lever a bit to see if something was a little out of adjustment but no luck there either. The neutral safety part of the switch works fine.

 

It could be the switch, but could also be a disconnected wire. A test-light or multi-meter is your friend...

 

The Comet bulb sockets are commonly bad, check for voltage at socket before digging into switch.

 

Yo mean bulb socket in metal housing? My bU lights have not worked in long time, but, the car would only start in Park. The socket has power, bought new NS switch but it supposedly wrong one according to a transmission shop doing work on car few years ago.

 

If socket has power, the switch is doing it's job.

Usually a issue with the socket ground.

 

Comet rear sockets are different from a Maverick. The Comet is a plastic socket with a separate ground wire. The maverick sockets are metal and ground to the tail lights. the back up lights are in the neutral start switch.

 

There ya go. Use a dual contact #1076 bulb.

I wound up modifying wedge bulb sockets from a '88 T-Bird. Only required modifying one of the locking tabs to fit perfectly in Comet housing.

 

The sockets on my Comet are metal and attach to the plastic taillight housing. I held one lead on my test light against one of the contacts inside the socket and the other against one of the bolts that attaches the taillight housing to the rear panel. With the ignition key in the on position, still no luck. I am also wondering why my bulb sockets are metal if they are supposed to be plastic. They appear to be original factory sockets. Am I correct in assuming that the car doesn't have to be running to do this test?

 

Only one contact will have voltage, other is ground.

Voltage supplied to socket only when ign is on and lever is in reverse. No doesn't have to be running.

Only function of brass base shell, is to hold bulb in socket. It is not ground.

 

Thanks. Touched first probe to one contact, the other probe to the other contact, still no voltage. Unless it is a wiring issue, it must be the neutral safety switch. I can't find any place where the wiring has been tampered with. Is it unusual for the neutral safety part of the switch to function and only the back up light portion to fail, or is this fairly common?