I'm getting soooo frustrated with our Suburban. About a year ago, the driver seat button went crazy, where if you pushed the button forward, the seat would go backwards, and if you pushed it backwards, the seat would go forward. We just left it, didn't bother fixing it. Well, a few months ago, the speedometer went crazy, where every now and then we would be going 20m/h and the speedometer would say we were going 120m/h and when you turned the truck off, the speedometer would never go back to zero. But after a few days however, it would fix itself, well recently it's gotten worse and it just keep doing it and doint it. We never know how fast we are going any more. Now about a week ago, the seat warmers went crazy, we hit the buttons to turn the seat warmers on and after a few seconds they would turn themselves off. Some times they stay a little longer but they eventually turn themselves off as well, if you turn them back on, they eventually turn themselves off whether after a few seconds or a minute. Now we noticed that the temperature reader on the rearview mirror has also gone crazy telling us that it is 6 degrees out when we know it is like 45 or what ever. What is going on?!!! Are all these things related?? What is wrong with our Suburban?

 

I would suspect a grounding issue or a short somewhere..
Where that poor connection is , is a guess... have you added any aftermarket options? if so start with those connections....
Check the battery ground cable, it needs to be clean and solid at both ends and the cable should be in good shape....

 

my burb does all the same issues yours is doing except the speedometer issue. it did have the speedo issue when we bought it but the dealer replaced the cluster. also had that happen in an 03 1/2ton truck. had to replace the cluster as well. i did a search and found an older post on checking the grounds, battery and one on the frame rail drivers side. if it ever gets above 15* im gonna check all these and clean them to see if it helps. if it does i will let you know and maybe you could try that.
also found a post regarding the backwards seat controls stating that the seat controler can be flashed and programed by the dealer to get back to normal. as mine is the same.

 

My 92 burb had a something like that & I found that the grounding straps had rusted and broken off. replaced them & never had that prob again.
Hope this helps.

 

My wifes 04 tahoe had simalar problems. The front passenger side seat rail had rubbed the wireharness bare. It might help.

 

I have a similar problem with my '05. The heated seats don't always work and the left and rear view mirrors sometimes look tinted to the point you can barely see the temp and direction, then they straighten out for no apparent reason. The RH mirror is not affected.

 

FWIW, the RH mirror doesn't have the dimming function.