My speedo stopped working in my 110mph guage cluster. Pretty sure the motor went bad as the needle had a lot of resistance when I took the cluster out.
Anyways, I figured I'd upgrade to a 145mph, and after install, I notice the tach is way off. So I replace it with my old tach out of the old cluster, and it does the same thing!
So my theory is that the 145mph cluster has an electrical problem as far as the tach is concerned.

So I guess the question is:

If I simply pull the speedo out of the 145mph cluster and put it in my old 110mph cluster, will it read right? Or will it read as if I had a 110mph cluster in there? I'm not sure where exactly it is calibrated at....I would assume the cluster's electronics, though it may be in the motor it's self. Any help would be appreciated. Thank you in advance

 

what kind of car is this in ? and is the speedo elect. or mech. ?

 

90 RS, electronic speedo