Problem: Temp gauge doesn't go up (stays on C) & radiator fan doesn't kick on at idle (or at all, fwiw). I tested the temp sender just now and it started at 5xx something ohms (Prelude specs say 142 for a cold engine, 133*F) and it went down to about 215 by the time the engine was pretty warm (when the idle dropped) (Honda says 32-49ohms for a warm engine, but that's 185-212*F) I'm not really sure how to tell when the engine is up to that temperature, but I'm guessing it was probably at least 133* by the time the idle dropped down. I let it idle probably 5 more minutes and the fan never came on. Should I keep waiting?

What I'm mainly wondering is if the temp sender and fan switches are independent systems, or if the faulty sender could be making the fans not come on. I know they're both cheap fixes, but I'd rather save the $25 or another trip to the store if I don't need the fan switch.

BTW, I know for sure that the thermostat works and the fan works when I jump the line at the switch by the stat. Also, the guage lights up fully when I ground the sender wire, so none of those are problems and it's most likely not a wiring issue. We're talking about an H22A in a 4th gen if that matters.

Thanks in advance.

 

I would replace the temp sender and go from there... Or at least pull it and inspect the sensor. It could be covered in build up or something, you never know.