For the past several months I have been serching on here about speedometer problems and tring suggestings from there, but none seems to have the same problem that I am having. I have a 91 cherokee limited with electronic speedometer, it works most of the time when at dead stop, then 0 when I start moving. It sometimes will jump around when driving, but not often.
I replaced with other speedometers with no change,so I put old one back because circuit board the back of speedometers where different, tried with two different electronic speedometers. I also changed the sensor on the back of the t-case, no change in operation, all other guages work fine.
I'm not sure where to go next, any help would be great.
Thanks

 

91s had electronic speedos?

 

Ya 91 has electric speedo with speed sensor on the back of the t-case

 

Maybe the speedo gear is worn out?

 

And you checked the continuity of the wiring, to make sure there are no breaks or shorts? Because if there is an intermittent short to ground, you'll probably get no reading on the speedometer when it shorts, or "jumping around." Is it worse when the vehicle is moving? Does it go haywire when you hit a chuckhole or a rough road? I'm betting on some kind of wiring harness problem. Can you run wiring outside of the harnes from the sending unit to the speedo?

 

Thanks for the reply. I checked that, gears look good.

 

Thanks for the reply. Bumps or rough roads make no difference. I did not check continuity, figured since it works at dead stop wires where ok, but I will check that and may run new wires to see if that makes a difference.
Have to wait for warmer weather

 

I found a dirty/bad connection at a connector at the firewall. Find the harness that comes up from the tranny/tcase and clean the terminals in that connector.

 

Are you talking about these speedos?

 

and thats the end of this thread ^