Sorry Old Blue, been off line for a while. The resistor to use should look like a "ceramic" fuse with colored lines encircling it. The colors indicate the ohms resistance of the unit. Should be a open wire coming out of each end. Attach one end to your sender connector and the other end to your wire going to the gauge. You can leave them bare to start with just don't let them touch metal as the reisitance will change. Let your truck warm up and see how the gauge reacts. By the way, I just purchased two senders off of Ebay. The senders look just like the one we got from Chevy Duty. Plan on putting the two loose ones out on the radiator overnight and then measure the resistance of each one as well as the unit in the thermostat housing. If the two loose ones measure differently than the one installed in the housing, I'm going to swap it out and check to see if it works more accurately. More on this in about a week.
