I managed to pull the cluster...and all the bulbs. Bulbs are all good. But from what I can tell,
those bulbs just run the idiot lights at the bottom of the cluster. Rest of the screen is still black. I am not sure how to proceed from here. I guess I can use my phone as my speedometer.
Hmmm..
You might try cleaning the contacts with some 800 grit sand paper, and rubbing alcohol..
Brandon was having some issues with his cluster due to the oxidation on the circuit board..After he cleaned the contacts his problems went away..
You can see the clean harness contacts on the left
compared to the oxidized ones on the right..
Here's more from that thread:
Speedometer Oddities
If that doesn't work you're going to have to look for an electronic cluster from any 1989-1993 MN12..
Your 93 (5.0) cluster is special because it doesn't stop at 85 mph like the rest of the electronic clusters available for the MN12..
Rest assured though..The other year electronic clusters will work..
Another thing you could try is to take the Instrument Cluster Display Module out of your current cluster, and swap it with a known good one..
The Instrument Cluster Display Module controls the Temperature, Fuel, and Speedometer display..
Here's a diagram of where it's at in the electronic cluster:
As much as I like the Electronic Clusters in these cars..If my car was equipped with one, and it started giving me fits I would probably just re-wire for the Sport Cluster..
I hope that helps..
Rayo..