Quad 4 coolant sensor wire colors

[yellow3800]

This should be simple.

QUESTION:  What are the wire colors going to the coolant sensors to  the '90 Q4 engine?

I have a 90 wire harness and [2] 91 engine coolant sensors.  I want the instrument gauge to work because it doesn't right now.

I assume there will be 3wires total, one two-pin and one single-pin.

I thinkg its a gry and gry-red wire pair going to a 2-pin sensor and I heated the sensor up, plugged it in, and no reading [still as if cold on gauge].  The other sensor has one pin.  I have a connector pretty much under the air box [can't reach coolant area, but what the heck] of grn and blu [2 pin].  Don't know where it goes.

both sensors came from a car with gauges, so I know even having the one pin sensor, still should give a gauge reading somehow.  Both sensors were good when removed.  Yes, both sensors run side-by-side.

I hope I provided enough info.

Andy  

[Cliff8928]

That single-pin sensor will be the one for the gauge.  However, it needs to be grounded in order for the sensor to work right.