I just purchased a 2003 Mustang GT and I unfortunately didn't notice the Water Temp and Oil Temp gauges not fluctuating correctly. When I start the car and it's cold the gauges immediately go just passed middle and stay there, they don't fluctuate at all. The tach seems to work fine but the Speedo is off by about 15 mph aswell. It does have larger tires and a possible gear change so that would explain the Speedo error.
Temp Gauges Not Working Properly. Please Help.
- Thread starter Saltlife850
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squeak93
15 Year Member
The oil is a pressure gauge and has a sensor down by the oil filter to replace. However, it should just go to the middle as it's more of a dummy gauge. It doesn't read actual pressure, just that there is X amount of pressure.
The water sensor is up on the rail by the t-stat, it could be bad as well. My water temp gauge "sticks" and moves if I tap on the plastic gauge shield on the dash. Other times it works perfect. My car had white face gauges added at some point from a previous owner so I'm guessing they jacked it up.
The water sensor is up on the rail by the t-stat, it could be bad as well. My water temp gauge "sticks" and moves if I tap on the plastic gauge shield on the dash. Other times it works perfect. My car had white face gauges added at some point from a previous owner so I'm guessing they jacked it up.
wmburns
SN Certified Technician
+1 on the oil sender. The position of the needle means nothing regarding the amount of oil pressure. It's an analog idiot light. Either shows OK or not-OK.
For the 1999+ model year the dash temperature gauge displays what the PCM "tells" it to display. This is different from the 1998 and older where there's a separate sender just for the dash gauge. So if trying to trouble shoot this problem it's necessary to know what the PCM "thinks" the engine coolant temperature is (ECT).
If the ECT value is correct in the PCM and the dash gauge is not correct THEN the problem is in the cluster.
If the ECT value is not correct, then the problem is in the ECT sender, wiring, or system voltage (alternator/charging system).
There is a ground behind the center console that is shared with multiple devices including the cluster, GEM, and radio. It's frequently messes up during a radio install. Not a bad idea to confirm that the cluster wires black wires with white stripes have a low resistance back to battery negative.
For the 1999+ model year the dash temperature gauge displays what the PCM "tells" it to display. This is different from the 1998 and older where there's a separate sender just for the dash gauge. So if trying to trouble shoot this problem it's necessary to know what the PCM "thinks" the engine coolant temperature is (ECT).
If the ECT value is correct in the PCM and the dash gauge is not correct THEN the problem is in the cluster.
If the ECT value is not correct, then the problem is in the ECT sender, wiring, or system voltage (alternator/charging system).
There is a ground behind the center console that is shared with multiple devices including the cluster, GEM, and radio. It's frequently messes up during a radio install. Not a bad idea to confirm that the cluster wires black wires with white stripes have a low resistance back to battery negative.
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