No reverse lights - new switch

[hemmah]

My 69 911T reverse lights do not work. I checked the bulbs and they work. New switch added and lights still do not work.

Help

[Flat6pac]

Did you get the pin in correctly?

[Scott R]

Did you pull the switch and test it outside of the transmission? Also the grounds for the backup lights get corroded over time from road debris, try running a temporary ground to test.

[john walker's workshop]

check for 12V on one side of the switch and when in reverse, you should get 12V out the other side too. if that checks out, it's between the switch and the lights.

[ossiblue]

Remove the two wires from the switch and connect them together, bypassing the switch. Turn on the ignition switch and see if the lights come on. If they do, something is wrong with your switch/pin. If they fail to light, see if you have voltage where the wires are joined together at the switch. If you have voltage there, retest at the reverse light socket where the wire connects. If voltage is present at the socket wire connector, retest at the socket itself. If you have power at all the test areas, then a ground problem is likely.

[Bob Kontak]

Originally Posted by Flat6pac

Did you get the pin in correctly?

Was there a pin in there to begin with?

I just ordered a new reverse switch for my 81. When the pin would make the connection it (the switch) grounded to the transmission case from inside and blew the fuse in the circuit.

I went through the process JW and ossiblue talk of and I could not figure it out as I had continuity between the female switch terminals when the trans was in reverse.
Finally thought "what if" and sure enough the terminals grounded to the case.

Maybe too much of a story but their process along with Scott R's ground check will ferret the problem out.

You need a multimeter and ten minutes watching a youtube instruction video if you don't already have that tool/knowledge.

THE BEST Multimeter tutorial (HD) - YouTube

[hemmah]

Yes the pins are correct. I have the switched bypassed now through a manual switch. I flip the manual switch and the lights come on.

[hemmah]

No I have not checked the switch. New switch. But new switches fail too. I'll check. Thanks

[hemmah]

Thanks. I'll check for the 12V

[hemmah]

I have the switched bypassed now through a manual switch. I flip the manual switch and the lights come on. I'll check the ground. How does the switch activate in the tranny? fluid or gear or ??

[hemmah]

I'll check the ground. Probably it. I'm an EE and should know better. Do know how to use a MM. Thanks

[ossiblue]

Originally Posted by hemmah

I have the switched bypassed now through a manual switch. I flip the manual switch and the lights come on. I'll check the ground. How does the switch activate in the tranny? fluid or gear or ??

If you have the tranny switch bypassed and the lights come on, then it is not a ground issue, it is a switch issue. Begin by using your MM to check continuity between the connectors on the tranny switch. Put the tranny in reverse and connect you MM to each connector and see if you get continuity. If you don't, pull out the switch and see if you have the pin inserted correctly, of it the pin is even there! If you reused an old pin, it may have worn down and is failing to close the switch contacts. If the pin is the issue, you can either buy an new one or grind down a drill bit to the proper length--there are threads on this.

The switch activates when the pin is pushed outward by a lobe inside the housing as the gear is changed into reverse. Purely mechanical function.

[hemmah]

I see now. I think the pin is gone. Must have been gone since I bought the car 20 years ago.

Thanks for the help. I'm smarter now.


Take care
Steve

[hemmah]

Oh where can I buy a pin?