HEATER, A/C FAN WON'T SHUT OFF

[Crash1]

03 SIERRA, SLE, Z71, Ext cab, 5.3 auto .....

I was standing beside the truck, it was not running, hadn't started it for 2 days, when all of a sudden the heater/Ac fan came on, only way to shut it off was to disconnect the battery. I removed the heater resistor module, the plug was hot to touch. It looked good, not burnt, no resistance across resistors, slight grey corrosion on 7 pin connector. From what I have read, I suspect this to be the problem. Whucha ya think?

[00Silverado4x4]

If you are getting no resistance across the resistors then that is definitely a problem. They all should have resistance and be different for each one.

[Carder09]

Go ahead and replace the resistor and harness, Since its getting hot, only a matter of time before it only works on high and possible small fire.

Go ahead and replace the resistor and harness, Since its getting hot, only a matter of time before it only works on high and possible small fire.

[Doug_Scott]

If removing the module and unplugging it made the fan stop then you found the well known and documented issue and were halfway to having it fixed. Issue so common it created a recall in Canada that has likely run out.

[Crash1]

K, thanx guys.