I have a '76 911 with the 1976 wiring to the speedometer (150 MPH VDO gauge) and I'm encountering a problem. The speedometer isn't working at all, and is just dead and the needle isn't moving! I've checked the hot (red) wire, and it has 12 volts. The other wires are on tight and look to be very good. Here's what happened previously to the problem:
1)Sometimes one of the wires would come loose causing the speedometer to not work. Fix: put wire back on contact.
2) *yesterday* the speedometer needle would work intermittantly and before I pulled over to disconnect the wires so that it wouldn't do any damage, the needle rapidly and randomly jumped up and down.
Now: Today I've found some bad connections and fixed them in 2 of the wires thinking that would solve the problem. I've reconnected everything, and the speedometer is still not responding at all! I'm pretty sure I've got everything connected correctly. What could be causing the speedometer not to work? Could the sensor be bad due to the wires being loose?
Thanks
P.S. I've set up my wiring as shown in the photo in this thread:
Speedometers