20round

i tested my gauge in the dash by grounding it out and it works properly. now how do i test the sending unit? i looked on line and could not find what to set the multi meter at to read the unit? can someone give me a pointer here? the engine does not seem to be running hot. i used a IR gun and its 180-190. but the gauge is pegged at 240 or beyond. thanks troy...

Donald #31176

I have the original sender in my car. At 180* the sender registers 135 ohms.

Powershift

You can check sender by measuring engine temperature with IR gun and then checking sender resistance from sender tip to battery ground OR you can remove the sender and put it partially in a water bath (bottom sender end) and heat the water and use a thermometer to measure temperature and resistance from sender tip to sender body. Your choice. If doing with sender in engine, start engine from cold and measure rising temperature with IR and ohms with multimeter at the same time and reference point.

No two people agree on exactly what the sender resistance should read vs temperature, but here are two good ones to use;

Temperature/ GM Blueprints/ Willcox Website specifications for 1965 temperature gage calibration

100 F/ 350 ohms/ 340 ohms

180F/ 105 ohms// 128 ohms

210F/ 76 ohms/ --------

240F/ 72 ohms/ 68 ohms

GM Blueprint information courtesy of Ken Anderrson, the guy who manufacturers and sells the GM licensed C2 reproduction dash gages (temp/fuel/amps/oil)

Larry

mrtexas

JohnZ comes thru again: https://www.corvetteforum.com/forums...uge-issue.html