jras312 Posted June 11, 2017 Share Posted June 11, 2017 Shortly after I bought the car last fall I did head gaskets and timing belt, I had everything apart and was cleaning things up here and there trying to make her reliable again, noticed there was a resistor installed inline with the wire that runs from the temp gauge to the sensor. It obviously wasn't stock to I just removed it and reconnected the wire how it's supposed to be. Ever since I did all that work the temp gauge has never gone above where it reads in this pic. I've installed a new OEM thermostat, OEM temp sensor, and even a new OEM gauge in the dash cluster. Nothing has changed. I grounded the wire to check the gauge and it pegs to the MAX just like it should. So why would there be too much resistance not allowing the needle to reach where operating temp should be? Also, it's in the 90's today in Iowa and the needle still won't go any higher. What else can I check? I've been battling this for far too long for such a simple thing like the dang temp gauge. Link to comment Share on other sites More sharing options...
RustyRuu Posted June 11, 2017 Share Posted June 11, 2017 what is the temperature reading at off the obd2 scanner if you have access to one? Link to comment Share on other sites More sharing options...
jras312 Posted June 11, 2017 Author Share Posted June 11, 2017 what is the temperature reading at off the obd2 scanner if you have access to one? Last I checked it was around 170-180F. I was going to run to oreilys here in a bit and borrow their scan tool to check again. Radiator fans seems to be operating like normal. I've verified 12v at the GW (green w/ white) wire at the gauge, and verified ground by running a jumper wire straight from the sensor wire to the battery ground. No change. Link to comment Share on other sites More sharing options...
RustyRuu Posted June 11, 2017 Share Posted June 11, 2017 I thought we were suppose to be closer to 190F/200F on the hot days. but i don't know if that would change the gauge on the dash too much. where does the gauge needle sit at when the car is off? Link to comment Share on other sites More sharing options...
jras312 Posted June 11, 2017 Author Share Posted June 11, 2017 where does the gauge needle sit at when the car is off? Right between the "c" and the first small hash mark at the bottom. Exactly where it's suppose to. Link to comment Share on other sites More sharing options...
Setnev Posted June 12, 2017 Share Posted June 12, 2017 In the service manual, there should be a section for electrical diagnostics. The electric diagnostics should give you resistance readings for the wires that lead from the temperature sensor to the gauge. You need to test that wire to see if you have any unusual current fluctuations in the line. Second, look at the mounting of the temperature sensor. The crossover pipe is known to get a little bit of deposits on the threads of where the sending unit is. This is what give the ground signal to the gauge for proper reading. Last, if you pick up a digital temp gauge and wire it to the connector, compare it with the OBD readings that should help tell if the gauge is reading bad or the sensor. Link to comment Share on other sites More sharing options...
jras312 Posted June 13, 2017 Author Share Posted June 13, 2017 Second, look at the mounting of the temperature sensor. The crossover pipe is known to get a little bit of deposits on the threads of where the sending unit is. This is what give the ground signal to the gauge for proper reading. YES!! Thank you for that idea! Never thought of the actual ground through the sensor. I didn't clean it up properly yet because I didn't want to get coolant everywhere. For the time being I just added a ground strap on the intake manifold and wrapped it around the sensor. Link to comment Share on other sites More sharing options...
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