Driving home from work friday my 2002 started to surge slightly. At the next stop light I noticed my temperature gauge going from pegged at the bottom to pegged at the high side. Once that started happening I had to limp home at about 10mph whenever the gauge was high and then would get a burst of power when the gauge was hot. I talk to Tim from TRE diesel friday and he thinks it sounds like a bad gauge cause the truck to run in limp mode. My question is where do I start trouble shooting this gauge? Is the temp swith right next to the thermastat? Where should I disconnect to eleminate that gauge from the system? Any help would be appreciated.

 

it's not the Gage, it's the temp sensor which also sends a signal to the ECM

 

T-stat part number 05015708AC Thermostat

To determine if the thermostat is defective, it must be removed from the vehicle (Refer to 7 - COOLING/ENGINE/ENGINE COOLANT THERMOSTAT - REMOVAL).
After the thermostat has been removed, examine the thermostat and inside of thermostat housing for contaminants. If contaminants are found, the thermostat may already be in a “stuck open” position. Flush the cooling system before replacing thermostat (Refer to 7 - COOLING - STANDARD PROCEDURE).
Place the thermostat into a container filled with water.
Place the container on a hot plate or other suitable heating device.
Place a commercially available radiator thermometer into the water.
Apply heat to the water while observing the thermostat and thermometer.
When the water temperature reaches 83°C (181°F) the thermostat should start to open (valve will start to move). If the valve starts to move before this temperature is reached, it is opening too early. Replace thermostat. The thermostat should be fully open (valve will stop moving) at 95°C (203°F). If the valve is still moving when the water temperature reaches 203°, it is opening too late. Replace thermostat. If the valve refuses to move at any time, replace thermostat.


To test cluster do the following
Begin the test with the ignition switch in the Off position.
Depress the odometer/trip odometer switch button.
While still holding the odometer/trip odometer switch button depressed, turn the ignition switch to the On position, but do not start the engine.
Keep the odometer/trip odometer switch button depressed for about ten seconds, until CHEC appears in the odometer display, then release the odometer/trip odometer switch button.
A series of three-digit numeric failure messages may appear in the odometer display, depending upon the failure mode. If a failure message appears, refer to the Instrument Cluster Failure Message chart for the description and proper correction. If no failure message appears, the actuator test will proceed as described in Step 16. INSTRUMENT CLUSTER FAILURE MESSAGE
Message Description Correction
110 A failure has been identified in the cluster CPU, RAM, or EEPROM. 1. Replace the faulty cluster.
900 The CCD data bus is not operational. 1. Check the CCD data bus connections at the cluster.

 

I did the check of the gauges and they work 4.0. Replaced the thermostat on friday which I later thought about and that should not be the issue. If I am thinking right the temp swith should be right next to the thermostat there. I pulled that connection and used the multimeter on the connector. 4.68 volts which I believe that it is a 5 volt system. I ordered a new temp switch which should be here tuesday. I am hoping that is the issue. However I pulled the codes and I came up with a lot under the ECU. They are 0112, 0117, 0118, 0237, 0342, 0562, 0606, 1488! Could I possibly have an ECM issue? I have an edge J/A on, should I disconnect that? I am hoping its not the ECM!