How to check continuity on a C2 temperature sending unit

[Michael M.]

I have the temperature sending unit out of the car. How do I check continuity with a ohm meter? Also what should the ohm meter read when the sending unit is out of the intake manifold?

[Jimmy G.]

Re: How to check continuity on a C2 temperature sending unit

Easy to check One lead on the bottom and one lead on the connector There are several past threads on this but I think the room temperature reading should be close to 700 - 800 ohms. If you heat the bottom with a lighter the reading will decrease substantially

[Larry M.]

Re: How to check continuity on a C2 temperature sending unit

If you really want to check it out for reliability test it at 180F and 210F in a glass of hot water with a thermometer.

Ohms should be 105 and 76, respectively: 105 at 180F and 76 at 210F

Larry

[Chris T.]

Re: How to check continuity on a C2 temperature sending unit

There is great article on the ncrsmac.org website about testing gauges and senders (their whole website is filled with awesome information). Link below, but these resistance numbers are "ballpark numbers" because of the variable nature of your dash gauge (different gauges together with different senders, will read different). Ideally, with a known water temperature, you will need to find a sender that coincides with the reading on the dash (180 water temp - 180 dash reading). You may need to try/purchase a few different senders before you get close.
http://www.ncrsmac.org/ed/Electrical/Troubleshooting%20Corvette%20Gauges.pdf

[Larry M.]

Re: How to check continuity on a C2 temperature sending unit

There is great article on the ncrsmac.org website about testing gauges and senders (their whole website is filled with awesome information). Link below, but these resistance numbers are "ballpark numbers" because of the variable nature of your dash gauge (different gauges together with different senders, will read different). Ideally, with a known water temperature, you will need to find a sender that coincides with the reading on the dash (180 water temp - 180 dash reading). You may need to try/purchase a few different senders before you get close.
http://www.ncrsmac.org/ed/Electrical/Troubleshooting%20Corvette%20Gauges.pdf

I agree that both senders and dash gages have tolerances and a "sweet spot". However, the numbers I posted came from Ken Anderson, who was reading from GM blueprints for the sending units. Ken is the manufacturer of the GM licensed reproduction senders and dash gages, and an occasional NCRS poster. So maybe he will see this and reply as well.

But his comments and these exact numbers should be in the archives as a quote from him. That is where I got them a few years ago.

Wilcox website also has great info on this subject. Wilcox rebuilds the OEM gages for us Corvette guys. http://repairs.willcoxcorvette.com/c...re-gauge-info/

Larry

[Jimmy G.]

Re: How to check continuity on a C2 temperature sending unit

Just did a very unscientific test on some sending units I have. Basically at room temperature the original GM units run from high 600 to mid 700's in ohms Aftermarket units appear to run in the mid 500's Just an FYI on 14 units tested.