Hello everyone,

I am in the process of troubleshooting some strange idle problems on my car (see the idle gremlins post) and have started testing every sensor that has any influence on the ISC. One of these is the water thermoswitch (through the E/L unit). When I check the continuity of this sensor to ground, I get infinite resistance with the engine cold. Is this supposed to be this way? From looking at the shop manual, it looks like the sensor is supposed to read some continuity cold (low resistance), and above 1M ohm resistance when hot. Also, if this was the case, wouldn't I get a check engine light, or is this only if there is no resistance at all (short)? Thanks for any help you can give me!


Jon
'93 MB Touring
'85 Silver GSL-SE

 

As posted by Flybye :

Just take it out and OHM test it.
If you dunk it within 68F water, the sensor should read between 2.2-2.7 ohms
If you dunk it within 176F water, the sensor should read between .29-.35 ohms

If not, then replace it.