thealt

Having an issue with my speedometer cable not working unless I engage the parking brake.
It's been this way quite a few years, and sadly.... i know what caused it. Problem was between the steering wheel and the seat.
All other gauges, instrument lights, switches, etc are fine. Only the speedometer needle does register the speed when the parking brake is off.


Long ago I pulled my dash apart and replaced the speedometer cable and some other things. When assembling in the dark, I switched instrument cluster connections. (I blame the manufacturer ) During the test drive, I smelled electrical smoke and stopped. Realized what I did and swapped the connections to their correct location. Since then, the speedometer only works when the parking brake lever is engaged. One click is enough to do it. Parking brake light comes on, and the speedometer works. Been this way since 1997.

I don't see in the wiring diagram that these 2 components are linked, but since the tachometer is on the same circuit as the brake warning light, I suspect the speedometer pulse generator is part of the same instrument cluster circuit.

Possibly a bad ground? My initial thought was that applying the brake, powers the warning light, which powers the circuit to the speedometer, which powers the house that Jack built.

Before I tear into my dash, I welcome some insights on what to check and if anyone can confirm the wiring schematic for the pulse generator is on that same circuit.

Thanks. Alt