Hi,
I have an 87 4runner with a bad thermistor in the AC system. The symptoms are as follows:
The AC compressor clutch will not engage unless I short out (jump) the thermistor connection to the amplifer. I checked the resistance measurements at the disconnected thermistor plug and get an open circuit reading rather than the 1K ohm I expect. If I jump the thermistor, the clutch engages and the system cools nicely.
My question is: I understand the purpose of the thermistor is to cycle the compressor clutch at low temperatures to prevent freezing of the evaporator. If I leave the thermistor shorted out of the system, how likely is it that freezing will occur and will it cause any problems that can't be corrected by just turning off the AC for a few minutes? I live in northern California with relatively low humidity.
Secondly, is there any way to access the thermistor without pulling out the whole evaporator box? I'd like to avoid evacuating the system if I don't have to.
Thanks for any info! Mark