Having issues with my temperature gauge. Replaced the thermostat, coolant temperature sensor, and we're still having issues. Thinking it may be temperature gauge sensor, but we replaced it with an older one and when we started it up, the gauge when straight to hot. clueless as to what is wrong, any ideas?s, water pump is fine. It's a 2.2L, no turbo

the most expensive part of 3 possible replaced 2 times.
wow.
the sensor or the wires (end to end) are bad. (just one gauge fails?)
the service manual covers how this work.

I guess you meant the IP cluster engine temperature meter reads wrong and the engine thermostat is not bad, 23 years old and thermostats have design life of 7 years../
a scan tool set to scan PID, ECT sensor tells what coolant is doing.
189f to 213F is spec, temp range

the gauge coolant temp has:

Water Temperature Indicator Sender Unit
When the engine temperature is low, the resistance of the water temperature indicator sender unit (10884) is high, thus restricting the flow of current through the gauge and moving the pointer only a short distance. As the temperature of the coolant increases, the resistance decreases, allowing more current to flow through the gauge and resulting in a corresponding movement of the pointer.

these year trucks the gauge sender is not the ECU ECT sensor
and may be single wire sender.. try mostly fail this old, not the gauge
the wire on the sender can rust or even fall off.

possibly change the wrong unit
gauges work from a sender unit not a sensor
it is located next to the thermostat housing normally and has only 1 wire connection
they work by having power through the gauge to the sender through variable resistance that is affected by heat to ground
test disconnect the wire from the sender
turn on the ignition key , ground out the wire and the gauge should go straight to full hot
sensors on the other hand have more wires and relay the coolant temp to the ECM so that air/fuel ratios can be adjusted , and fans switched on as required

If you replaced the SENSOR and not the gauge SENDER, there's your answer.

The SENSOR sends the computer (ECM, PCM, ECU, etc.) the engine temp so it can make the adjustments to the fuel, timing etc.

The gauge SENDER makes the gauge read what temperature the engine coolant is.

Hope the helps.

Hi there,
My name is Steve. I can tell you that the barometric pressure sensor can, in no way, effect the temperature gauge operation. The gauge gets a signal from the engine computer which, in turn, gets a reading from the coolant temperature sensor. Your first step should be to have the check engine light diagnosed properly...starting with checking for codes. You likely have a code(s) relating to engine temperature or the temperature sensor circuit. Most common problems are erratic sensor operation and corrosion or oil contamination in the coolant temperature sensor connector. You will be time and money ahead by having a professional diagnose the problem correctly before deciding to buy any parts.

probably a faulty temperature sender unit
temp sensor unit which controls the fan)

What you are describing is a cooling system low on coolant or a sticking thermostat.
I might leave the thermostat out and drive it a few days to see what happens. There could be something in the system that is restricting flow, or it could still be low on coolant.
Its possible something is not right with air flow thru the radiator or the fan clutch. There could be a restriction in the ac condenser.

Its possible that your problem also stay in the Engine Coolant Temperature (ECT) sensor resistance changes in response to engine coolant temperature.

Keep in mindthat the sensor resistance decreases as coolant temperature increases. This provides a reference signal, which indicates engine coolant temperature, to the ECM.





Fig.: Compare the sensor readings with these values




Fig.: Location of the thermal sending unit (A) next to the coolant temperature sensor (B)

Keep us updated.

It certainly could be the sensor and it is mostly cheaper and easier to replace it as a first step.

Bear in mind the temperature gauge can only be reasonably accurate if it is supplied by the correct stabilised voltage and sometimes the instrument voltage stabiliser does cause problems...

I just had a similar issue with my 1995 Buick century. My issue started out with the gage being almost pegged with the car off. When I turned the key to run it pegged the gage completely. I first called AutoZone and they told me it was either the temperature sensor, thermostat, or gage.
I knew that my thermostat wasn’t bad because I replaced it a while back. I then checked my sensor; I unhooked the two pin connector of this sensor at the block and suspected the needle to drop to zero. This was not the case.
I then checked my wires using a multimeter to verify that there was no short at my firewall. My wiring was fine.
I then called a family mechanic and he instructed me that there is also a "temperature switch" that also is interconnected to the coolant temperature gage. I then found this switch which was threaded into the block near the firewall of my car. I unhooked the 2 pin connector and suspected that the gage would return to the neutral position. And sure enough it did!!
This could have been a heck of a lot easier if AutoZone could have told me that my car has a "temperature switch". But non the less it was only a $15 fix!

First try unhooking your sensors and switch to see if this is the problem, I would lastly suspect your gage to fail!

Good Luck

look on the intake it should be there