Getting back with a post regarding our resolution. The second sending unit from LectricLimited came with the same false low readings as the first. While I can fault their product (this one anyhow); I sure cannot say anything bad about their tech support. Out of the blue one day a tech called me to ask how the second unit worked. When I relayed that it was also giving a false low reading he told me that they had conducted a test with the one I had returned and found that it was out of specs. I had a lengthy discussion with him and he suggested that I purchase a resistor to use with one of the sending units we purchased from the auto supply. Which resistor? That is the big question. The auto supply sending units did not have enough resistance, theirs - too much resistance, but it would be a guess as to how much to add. The suggestion was to find a variable resistor, a potentiometer.
Hooking it up was simple enough. I did not want to splice into the wire going to the temp sending unit, so I rerouted that wire into the cabin and used a new (green) wire from cabin out to the sending unit. It took about a day and a half. A couple hours to solder up the potentiometer and find a suitable case for it and run the wire and swap out the temp sending unit; about a day and a half to correct the broken vacuum line to the heater control switch that broke clean off at the firewall while I was searching for a place to route the wires through...
I took the bird out for a run today and when we were at operating temp I dialed the gauge back down to the half way mark. I plan to do a bit more testing with the IR thermometer before zip tying the whole package up under the dash. I am pretty happy to be looking at 180* on the gauge and feel confident that it is pretty much correct!
Edit, when I returned from the test drive I put a multimeter across the potentiometer. It read right at 13 Ohms resistance that was added.
Last edited by Cal H; 02/13/1910:24 PM. Reason: To provide multimeter test result.
