My car has an after market temp gauge with the temp senor installed in the drivers side head. I replaced the stock gauge. The gauge pegs when key goes to the run position and drops back down once started. The stock temp gauge pegs when I ground the green wire on the engine harness.

I purchased a stock temp sensor but I would like to test the stock temp system before draining anti-freeze and installing stock sensor.

Can I simply boil water,connect the stock sensor to the green sensor wire, and drop it into the hot water too see if the system is working?

Any ideas?

 

Tricksters code chart

That has some voltage readings based on coolant temp, that may help you out.

I know *somewhere* I've seen the actual GM numbers for temperature based on resistance for a temp sensor, but can't recall where that was. I *thought* it was on the CTS troubleshooting chart, but I don't see it there.