Multiple meters not working (tach, oil, temp)
 

So I have a 9o chassis and ripped a bunch o shit out and had this problem and did lots of looking for a answer (web and wiring diagrams). These are what I came up with:

Each sensor could have been dead:
*check coolant temp sensor with an ohm meter, cold and hot should be different resistances
*igniter should have a sine wave coming out of it on the green/yellow wire
*oil pressure sensor I am not sure about but would think it would be the same as the temp sensor just with the car/oil pressure on/off

The fuse could have been shot but the fuel meter would also have to not work to satisfy that explanation

Bad ground could cause it but the lights (oil, cel, ect) wouldn't come on when the key is turned to on but the car not started.

The plug on the back of the cluster is dirty, partially unplugged, or some of the pins burnt up.

The plug on the passenger side under the dash is unplugged because you ripped the blower motor out or similar reason.

For me it was the last thing listed...but I checked the grounds just to prove the adage wrong. Thought I'd post what I found, perhaps it will spare someone else some time.