1994 Chevy k1500 bouncing speedo.

[94 Borba]

When engaging cruise control my Speedo bounces around erratically not as crazy as other videos I’ve seen but a fair amount from 7mph to 12mph as well as this same thing happens when I accelerate. However when I left off the throttle or disengage cruise control it goes back to my normal speed no bouncing or nothing. I’ve gotten a replacement cluster to see if that was the problem no luck. I replaced the speed sensor and again no fix so I’m kinda out of ideas and hope someone has a fix. To add everything like heating and cooling controls and every other gauge on the cluster works. It is just the speedometer that doesn’t work.

 

[redherring1551]

Not sure what the problem is but maybe a short somewhere? Trace the plug wires for the speed sensor maybe they need replacing.

Also check your grounds...I was having weird electrical issues and I literally went and replaced EVERY ground cable and when I pulled the old ones off I cleaned the bolts and the surface they contacted with. Grounds replaced seemed to solve my electrical problems.

Seems like you may have a one off kinda problem.