Q: Temperature gauge does not work - 1998 Mercury Grand Marquis

asked by on December 05, 2016

Replaced temp sending unit but temp gauge does not work. I ground sending unit at plugin and temp gauge needle pegged to (H) hot. Thinking gauge works. So I replaced sending unit, gauge still does not work at normal operating temp. Thermostat works well and cooling fan works as expected. I do not have an overheating problem. Just temp gauge not working. I do have 9.5 voltage at sending unit plug. I believe problem is between plug in and gauge, not grounding. Gauge did move when I provided a ground from the battery. Just need your second opion. Hope I provided enough info.

My car has 173000 miles.
My car has an automatic transmission.

You will need to test the computer to scan for data of the temperature sensor to see if the computer is reading the correct temperature as tested externally on the coolant sensor. If the sensor is not accurate then replace the sender. If the sender is accurate then you will need to have the temperature gauge replaced.

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