Dash Malfunctioning!

The dash in my 1991 oldsmobile 98 is flashing false warning signs, sometimes it switches to km/hr and you can't change it back. Any idea how to fix this or what could be wrong?!?!

I'd guess your ECM (engine control module) or "brain" is going south.

i've tried replacing the ECM, that wasn't the problem..

My dash always malfunctions, but not like you are describing. The odometer goes crazy sometimes. Sometimes I can read it, sometimes I can't.

So, what is the ECM, and what does that entail to replace? Is that expensive?
Thanks

The ECM is the "engine control module" and it controls all the electonics in the car (aka the "brain"). A reman'ed ECM is around $50 offa Ebay and it is located behind the passenger side hush panel under the glovebox.

If the ECM isn't the cause, then I would say that the connections to the dash need to be cleaned, or the dash cluster itself is going bad. That or the sensors sending information to the dash are faulty.

I bought an ECM off Ebay for $40! Thanks for that idea!

However, I guess we need it reset for our car or something like that. Do I have to take it to a dealer to get this done? Or is this something we can do ourselves?

Thanks!

No, you dno't need to reset it or anything. Assuming the ECM you got has the correct PROM chip in it, all you have to do is swap them out.

No, you dno't need to reset it or anything. Assuming the ECM you got has the correct PROM chip in it, all you have to do is swap them out.

We've already tried swapping them, and the screen tells us the "Please clean Key, Try again in 3 minutes" Can I swap PROM cards? Or what can I do?

Thank you!