Tach Problems?

[Wilstruck]

Tach is reading 500-1000 rpm off. When truck first started tach reads correctly. while driving it will start reading about 500 rpm under. when stopped at traffic light tach will drop to 0. Has anyone experienced anything like this. Im thinking maybe a sensor going bad. If key turned off it will reset and read correctly for a short time.

[f5fstop]

Check your connector at the instrument cluster. Probably not a sensor, since the tech signal to the cluster is supplied by the PCM (via class 2), and if a sensor was going bad, the PCM would set a code and illuminate the service engine soon light.
Could be the cluster going bad, or maybe someone has experienced this and knows the fix. But looking at the schematics, this is what it appears to be with my limited knowledge.

[Wilstruck]

That makes sence. I had the dash all apart installing sirius a few weeks ago, so connections could be the problem. Ill have to take it apart and check it out. I read somwhere that the motors in these clusters are common for failing . Has anyone else had any issues? Im 700 miles over 36,000 and did not purchase the extended. Guess this repair is on me!!!!!!! Thanks for the help.

[Wilstruck]

Whats more cost effective to replace or repair? If repair any sugesstions on where/who?

[Wilstruck]

Whats more cost effective to replace or repair? If repair any sugesstions on where/who?

[Wilstruck]

Went to dealer for #@##'s and giggles and they are replacing cluster under goodwill waranty. Thats a A+ for Gm.

[f5fstop]

Originally Posted by Wilstruck

Went to dealer for #@##'s and giggles and they are replacing cluster under goodwill waranty. Thats a A+ for Gm.

I was going to suggest that, nothing to lose, and with only 700 over, GM has been known to bend a little. Great news....