OP switch signal wire?? what color??

[85-m1028]

wondering what the "gray wire" at the 3 wire connector to the oil pressure switch is for.

If this is the signal wire for the oil pressure guage, what kind of guage would I need? I.E. brand or specific calibration that will work.

the engine is a 97, see sig..

[More Power]

wondering what the "gray wire" at the 3 wire connector to the oil pressure switch is for.

If this is the signal wire for the oil pressure guage, what kind of guage would I need? I.E. brand or specific calibration that will work.

the engine is a 97, see sig..

The 1998 GM book I have indicates that the oil pressure switch receives 12vdc via an orange wire (1.0mm metric cross sectional wire gauge) through the ECMB 20-amp fuse, and the output of the switch is a gray (1.0) wire, which connects to the lift pump.

The oil pressure sender has a low resistance when oil pressure is low and a higher resistance (~90 ohms) when oil pressure is higher.

Jim

[JohnC]

... oil pressure switch receives 12vdc via an orange wire (1.0mm metric cross sectional wire gauge) through the ECMB 20-amp fuse, and the output of the switch is a gray (1.0) wire, which connects to the lift pump.

The remaining wire, whatever color it is, is for the gauge and connects the gauge to ground through the variable resistor.

[85-m1028]

So I should be recieving 12v from the gray wire. I use that to power a relay for the lift pump?

I have yet to get any voltage indication from that wire! perhaps the pressure switch is bad? Would that keep the computer from giving fuel?

gray = votage to lift pump relay

orange = voltage supply ecm 20amp

brown = signal for guage

thanks :)