Gold TA

I know the 98’s had a different coolant temp sensor than the 99-02 (3 wire vs 2). My gauge started to ‘not work’ at different times, but it still read to the computer fine via scan tool. The previous owner replaced the gauge (unknown part) right before I bought it, and it worked no problems for 6 months. I have an original GM sensor coming in a week or so (nearly impossible to find it in stock), but could it be the wiring? Do two of the wires feed the gauge and computer, or does the computer pick up the temp someplace else? Thanks.

Y2K_Frenzy

I’m probably speaking out of turn since I’m new and not quite GM savvy yet, but a lot of times older vehicles have temp SENDER that operates the temp gauge and a temp SENSOR that “talks” to the computer.” If the gauge isn’t working I’d bet either the sender is bad or possibly the gauge itself. I could be way off on this though.

jetech

Hi Gold TA. I think the 3 wire sender your car has, the dark green wire goes to the temp sender. brown wire is senser ground to PCM. Yellow wire is sensor signal to PCM