I just installed a radio into my 2000 Chevy Blazer and now I noticed that my speedometer isn't working. However, the tach and all other gauges are working. I didn't notice this before the radio but I made sure to use the GM Wiring Harness Adapter when installing the radio. I am MECP certified and have been working on vehicles for quite some time now. But, I have never seen this happen before so I thought I'd post the question on here.

Please let me know if you have any ideas. I checked the fuses but nothing was blown as I expected. Since the other gauges are working fine, I almost think it is coincidence.

Thanks for your time.

 

Does the vehicle operate (shift, drive, run, etc) properly? If so, the speedometer driver in the cluster is likely at fault.

Do you have access to a scan tool capable of reading the VSS output?

 

yes, it runs, drives and shifts perfectly fine. I can have it scanned. What should I have them specifically look for?

BTW thank you so much for your help!

 

Just look for the vehicle speed and verify that the VSS is working. It sounds like the VSS is working properly and the gauge cluster has somehow failed.