Temp Gauge Not Working

[landonshaw]

My temp guage just stopped working. I have a Volvo Penta MD2040. There is power to the gauge, checked that. Is there a way to test the guage itself without replacing and checking that way? Not sure if it is the sending unit, and do not know where that is on the engine, so if you know can anyone help with that, or the gauge. Thanks

[b-rad]

Most temp senders are ntc sensors, meaning as the temp goes up the resistance goes down. You can check the guage by grounding the sender wire and the guage should peg out at max hot. That will tell you the guage is working. Testing the sensor is harder you need hook up a dvom (ohm meter ) and check the resistance of the sensor to the case with the engine cold, then warm up the engine and check again. You can often get the specs for the sensor by searching the product number that is cast into the sensor, but you are looking for a change in the resistance . As for where the sender is you would need to look for it, you can look here andtry ot find a picture.

[landonshaw]

Thank you, I tested the wire from the sensor to th e gauge and found it to be bad. Changed it and all is well. Now that it works I will test the guage and sensor as you suggested to see what it looks like when it works.