1990 R2500 Suburban speedometer not working

[vista_burb90]

For a while now my speedometer will hold at about 65 when running. Sometimes the needle will fall all the way to the right when off. Sometimes needle will end up at far left and then bounce when running or sometimes just hold at 0 when driving. Kinda odd…
Trip and odometer has no issue tracking mileage.
Cruise control works and shifts great too. Can anybody confirm my thoughts leaning toward a bad gauge?

M40 — TRANSMISSION,AUTOMATIC 3-SPEED(THM400-475/3L80)

Thanks!

 

[HotWheelsBurban]

For a while now my speedometer will hold at about 65 when running. Sometimes the needle will fall all the way to the right when off. Sometimes needle will end up at far left and then bounce when running or sometimes just hold at 0 when driving. Kinda odd…
Trip and odometer has no issue tracking mileage.
Cruise control works and shifts great too. Can anybody confirm my thoughts leaning toward a bad gauge?

M40 — TRANSMISSION,AUTOMATIC 3-SPEED(THM400-475/3L80)

Thanks!

That was my last square body Burb, but I never had that problem with it.... If you could get another gauge cluster and swap the speedometer out, that would confirm your theory....
Back in the day, this type of thing was usually a bad or loose speedometer cable. But these speedometers are electronic and run by the PCM (I think?).

 

[BKING33]

I had the same problem with my speedo. I just recently got it repaired by a repair shop that does gauge restorations.

 

[83Stepper]

Wonder if the speedo isn't getting the signal from the VSS sensor, or an intermittent signal causing it to bounce around like that. But if you can get your hands on another speedo to test the theory of it being a bad speedo, do that first. Probably be cheaper than swapping out the vss sensor since the cruise is working correctly and not being affected by the dropout/peg on it.

 

[Edelbrock]

I would buy a HUD display for the spedo. It projects the speed onto your windshield. That way you can see your speed without taking your eyes off the road. They plug into the cigarette lighter and work off of GPS. Plug and play, and way cooler than the dash gauges. $20.

Amazon.com

 

[gmbellew]

1990, I think, is VSS. but i am not 100% on a 2500. if it is VSS and no codes being thrown and cruise works i would strongly suspect the speedo gauge itself is the problem. because if the VSS were not sending the signal to the ECM, and code would be thrown.