Heres what its doing...

This car has a Tanks Inc EFI Tank, and its got the correct fuel sender in the tank. I grounded the sender to the chassis,

Now. Key on, with roughly 5 gallons in the tank it reads just over 1/4 tank. As soon as I turn the Dash lights on, Headlights on, and thumb wheel is turned on for back lights. The fuel gauge will go to zero. I have put a solid state voltage limiter in the cluster.

Heres what I have done to correct the issue.

Cleaned every ground. made several extra straps for ground. Ran a ground from the battery to the sender, tried OE sender, has new fuel gauge in the cluster, cleaned circuit board contacts. tested board, made a ground from cluster to dash frame, cleaned ground from frame to column, tried different thumb wheel dimmer switch. all have same issue, as soon as back lights in cluster come on the fuel gauge drops to zero.

I tried a different voltage limiter and with that limiter it will peg to full when back lights are on. I can wiggle the limiter and get no change. Ive tried to check power behind the dash but its very difficult to get my scrawney ass back there to test, but Im going to grab some alligator clamps for my DVOM and test again. I thought maybe the battery was low, so I ran the test with 13 volts from my charger on it and it did exactly the same thing........

ANY POINTERS, will be greatly appreciated. New dash harness, New engine harness, new forward lighting harness.....


Thanks in advance