B2200 TEMP Gauge

What all is involved with the temp gauge on these trucks? I've replaced the temp sensor, but the gauge still doesn't budge. Trying to figure out if something else is unhooked somewhere.

The gauge is supplied power by a voltage regulator in the speedo cluster. Unplug the sensor connecter and put a volt meter on it (+ on the connecter and - on the block or a good ground) and see what you have. I can't remember off the top of my head but I think it's either 2 or 7 volts.

Do all the other lights and gauges on the cluster work?
Engine light, charge light, seat belt light, etc....?

The fuel gauge is powered by the same regulator, although at a different voltage. So if you have trouble with that too, that would also point to a regulator problem... although the gauge sender in the the tank is the most common reason for an inaccurate gauge reading.

everything else is working fine. Sender in the tank (and the tank) are brand new and do work. Every other indicator and dash light works, just the temp gauge that does nothing.

OK. Then check the voltage as I mentioned (with key ON). If you don't have 2 or 7 ( I think) then you can trace it back to the cluster and see if you have voltage leaving the cluster. If so, the you have a broken or weak wire somewhere. If not, then the gauge is bad. It will probably be the a Yellow/White Stripe or Yellow/Black Stripe wire leaving the cluster.... it might change it's colors by the time gets to the sensor connecter itself depending on what year your truck is. In either case, it should be and end wire on the 8 wire connecter going into the cluster.

One more thought. You are looking at the correct sensor, right? You have one for the ECM, one for the temp gauge, and one for the PTC heater (in the lower tank of the radiator.) I don't know the B2200 like the back of my hands, but I'm guessing it's in the same place as the B2000, right near the thermostat housing / water outlet. I just had to splice a wire and connector back on to the main harness of a B2000 last weak as a previous owner had cut the wire and connector off. That wire should be Yellow/White at the sensor.

Hmmm - I thought I had replied before work with something similar...yes, on B2200 that's the sending unit for the gauge: near the thermostat housing, somewhat hidden. Most often the wire/connector is bumped off. A sender like that needs to make contact with engine case to "close" the circuit.

If you touch the wire to engine ground metal, the gauge needle should go to the top.

Easiest way to test the gauge. The sensor should have a bullet (round) electrical terminal on it. I think the other temp sender on the motor has flat blade terminals.