So on my 92 truck the speedometer and odometer quit working intermittently. and only for a few seconds to a minute at a time. I think i've narrowed the problem to a wiring problem from the harness on the fender to the speedometer head unit and here's why:

The cruise control still works while the speedo/odo quit working. So since the cruise keeps working the sending unit to the computer has to be good, right?

I've cleaned the connection at the speedometer head and at the bulkhead through the firewall. And looking at the wiring diagram there is a junction where the signal from the sender branches to the computer and then to the speedo head.

Am I right in my diagnoses?

thanks.

 

So far. Fault has to be between the wire splice and the eyeball, and could be in the speedo itself, ie a bad solder joint.

 

J_martin, thanks for the response and confirmation. One thing I didn't mention and should have is that I've got another speedometer gauge cluster from a wrecked truck with ~40k less miles and put that cluster in for a couple days. Same issue. So it has to be in the wiring between that splice and the head unit.

thanks, Aaron