bad speedo revisited

[RickPA]

My speedometer is still going up 50 and staying there after about 35 minutes of driving then it works OK after sitting with the key off for a while. Now my fuel guage is starting to get wacky. It seems to wander a lot and reads high. I've also had 2 cluster instrument lights go out in the last month.

Good news is that truck runs fine and the problem seems to be localized to the cluster.

Any Electronic wizards out there got a clue about what's going on?

 

[BuffaloXplorer]

Don't think the speedo is anyway related with the electrical components in the cluster - i think it's determined by cable means.

I had a similar problem in one of my other cars and have only one tip: When the speedo is working, pay attention to the rpms. Write down local speed limits (or 5-10mph increments) and the corresponding RPMs - that way, if/when it does totally fail, you can at least judge your speed by engine speed.