officer_nasty

I got a 96 mustang gt which has 2 Engine Colant Temperature Sensors.

Book says that the ohms should be between 58,750-40,500 ohms when cold and 3,600-1,840 ohms when warmed up. Harness should be around 5v.

I tested them last night and this morning and this is what I got:

Driver side: (Grey sensor)
-29.1k or 29,100 ohms when car was cold.
-2.80k or 2,800 ohms when cars was warmed up. (correct according to manual)
-The harness tested at 5.18v. (correct according to manual)

Passenger side: (Blue/green)
-.36k or 360 ohms when car was cold.
-.03k or 30 ohms when car was warmed up.
-The harness tested at 4.63v.(correct according to manual)

My book only gives instructions for one ECT sensor. Are they both suppose to be measured the same or they completly different? If I replace them do I just get any ECT sensor or is there a difference between the grey one and the blue/green one?

FlamingoGT

Did you do these tests with the harness connected or disconnected?

officer_nasty

I did it with the harness disconnected.

Went to autozone and the driver side (grey switch, Coolant Temperature Sensor) tested at 33.2k and I tested mine this morning and it tested at 32.9 so I'm guessing that one is cool.

I also tested the passenger side (Blue/Green switch, Temperature Switch?) and mine tested at .40k and autozones had a brown one but I think it was the wrong one, that tested at 2.6K I think.

I'm going to check at another store if someone doesn't tell me what the ohms should be on that.

cliffyk

The values are of course temperature dependent, here a the chart from the '02 shop manual showing the expected output voltage (harness connected, key on), and resistance (harness unplugged):



29.2 kΩ would be about right for a 75° to 80°F coolant temperature, as is the 2.8k at 194°F or so. Also these are not precision sensors, so a variance of +/- 2% to 3% would not surprise me.

The other sensor seems defective.