it's the collant temp guage i think... the one on the instrument panel, beside the speedometer.
I hopped on PT and found some stuff about fan resistor, switch, and the relay between the headlight and battery. All of these have been switched with known good ones. I read something about a motor relay above the blower motor. I can't seem to find it...
'91 3.0L PLX MTX
'92 3.0L PLX ATX
Always a work in progress