sierra speedometer wacky!

[tasher]

My 2004 sierra 4x4 ex/cab long bed speedometer started reading 20mph at idle in my driveway. After researching the problem, I noticed that it is back to normal. This was over a 5 day period. Am I looking at a speedo head which is about to go out?, and can I do this repair w/out the dealer?
ct

[CBreck]

This is a common problem. You need to replace the stepper motor. My speedometer has acted up 2 times and corrected itself. Sooner or latter I will need to buy a stepper motor. The same motor is used for all of the guages and there ia 1 school of thought that says you should replace all of them while you are at it. Here is more information: http://quadrasteerclub.infopop.cc/ev...2/m/1301039081

[ChevyHDGert]

My wife's 2004 Yukon did this, it was reading wacky too, at one time it read 120 mph when we were doing about 30.

There is a recall or TSB on this (we got a letter from GM). The whole instrument panel is warrantied up to 70,000 miles and is replaced by the dealer if it is still under the 70,000 mile warranty.

[sonjaab]

Depending on the year and mileage GM is repairing them for free.
This may apply to your vehicle:
TSB #030849020 -- INSTRUMENT PANEL CLUSTER (IPC) GAUGES INOPERATIVE. *TT (NHTSA ID #10005590, NOVEMBER 01 2003)

Its best to call the GMC 800 customer assistance center and have you vin # and mileage handy. Your vehicle still may be covered for the free fix.

IF NOT COVERED.........There are a couple of cluster rebuilders on e-bay that will
repair the entire cluster for less than $200. If your handy with a wrench its
pretty simple to remove the cluster yourself.

[tasher]

Thanks for all the great info concerning my speedo. This site rocks!!

[MikeElectrician]

I fixed my speedometer!

I drive a 99 Chevy Express 2500. A few weeks ago the speedometer suddenly went crazy. It would show like 90 when I was doing 30, or go down to zero and ABS kicked in (this was when I found out I have ABS). I went online to find a solution and was amazed my problem was pretty common. Expert techs were replacing a lot of parts but getting nowhere. Sometimes the speed sensor gets replaced and the problem goes away, than comes back. I noticed nobody said anything about the wire harness, only that it should never be cut or spliced.

I know from experiance that a little dirt or corrosion plus sensitive electronics can lead to big problems. So I used electrical contact cleaner. I didn't know which part was the VSS so I cleaned all the tranny connections. I also cleaned the ABS module. I drove 200 miles since then and my speedometer is smooth and matches my GPS. Except for battery and starter everything under the hood is factory original and works, 150k miles. The only time I ever saw the check engine light was when I tried E85.