Heater fan speeds

[Canuckxxx]

I was only getting high heater fan speed on my 1998 GMC Sierra 1500. So I replaced the fan speed resistor behind the glove box. Now I get low speed and high speed but not the two medium speeds.

 

Does that sound like a bad speed selector switch? Or could it be that caused some of the resistors to touch each other when i put the new resistor in?

 

Any help will be appreciated

Brian

[arcasey]

I'm not sure if what you are describing is the problem, but I had a similar experience on my 96 K1500 where the fan speeds were intermittent. Sometimes they would work and sometimes they wouldn't on all speed settings. Thought my issue was the selector switch as well until I talked to a mechanic and he told me that 95% of the time on those model trucks when you are having issues with fan speed selection the blower motor is actually going bad. Replaced the blower motor and everything is working again. Honestly, with the age of the truck, I might would start there before I started chasing an electrical issue they may not be the culprit.