my 2003 water temp gauge needle stays on cold

Hey Guys, my 2003 tacoma 4 cyl water temp gauge needle stays on cold does not move at all.. My heater works fine. Any ideas what is causing this? What should I check?

Thanks in advance

Charles

 

Thermostat...

 

If the thermostat was stuck open, then the heater wouldn't work properly.

The first thing I would check, is the coolant-temp sensor. Either it has failed, or the connector is detached or loose.

 

do what the guys do in those prop planes when one of their gauges doesn't work. Take your finger and tap on that area and hope that it works.

 

Hey Guys, I disconnected the connector from the water temp sending unit and grounded the only wire going into the connector. The truck was running. No change in the gauge needle, still at bottom of gauge. Was that a valid test?

Thanks

Charles

 

Possibly, it should have moved, but that is dependent on the type of sender, if the ground increases or decreases with temperature.

Using a cold vehicle and an ohm meter crank the truck and use the ohm meter to determine the sender is functional. Make note of the cold and warmed up ohm readings. Then pull the cluster and check the harness at the gauge and see if they correspond. If not you possible have a bad harness, if they do, it is a bad gauge.

Have you or anyone else had the cluster out? Check to see if it has a bad/loose connection?

 

Thanks Darryle I have not had the cluster out to check that connection or the gauge.

My next step is to follow your suggestions.

Thanks again

Charles