Speedo Issue on 94 YJ 2.5

Hoping somebody can point me in the right direction. I have a lot of CJ experience but YJ's, not so much.
This little red YJ 2.5L runs well but the speedo (digital) will quit working after about 3 miles. Within a couple more miles the CEL will come on. It never runs bad It will start working again if you let it sit overnight. Seems to be associated with temperature,,, maybe? Pulled the cluster and cleaned all contacts, no difference. Cleaned the contacts on the sensor on the tranny, still no joy. Ideas? Ever hear of a sensor failing when warm? I don't like resorting to changing parts but that maybe whats required???

 

If you got a CEL, I would first check and see what the error code is. As it will remain in your computer until you disconnect the battery.

 

Forgot to include, the code it is showing is the 33, which is the a/c clutch relay. No a/c on this YJ but I've read that code can mean other things not related to a/c? Always ends with 55, which is end of codes, normal.

 

You could check to see just what the a/c sensor is hooked up to affect a vehicle w/o a/c. Sometimes temp can affect sensors as heat can shrink metal contacts breaking a connection. I would suggest starting with the vehicles speed sensor.

 

I was really thinking the other direction... the metal expands when it gets hot and is shorting out the circuit.

 

Yeah, funny thing is, most thought on the code 33 is it will always be present on a non-ac jeep but should not activate a CEL. Same as the code 12 battery disconnect. Those codes should not activate the CEL yet here I am with a CEL (after the speedo drops out) but just a code 33. I checked out the sensor and while it looks good. Who knows what happens after 3-4 miles. If it would just stay broken, I might have a chance. Thanks for the input. I might just buy a replacement and cross my fingers.

 

how about checking the sensor when it gets hot ? Would that be possible ?

 

Maybe, but I'm not even sure how to check it. 1 bolt and 1 three wire plug but once warm, is there a way to check for open circuit, resistance or output? Not sure how or what to check. Thought about spinning it by hand or egg beater hand drill??? I know the 3 wires are 8v in, ground and signal...

 

I’m not sure we’ll see what the smarter guys has to say. Stand by.