KyleF

So, done some researching and read some threads but none seem to be like my issue, at least to say I didn't find it. It's probably there. So, I don't have heat, but no hissing noise. Also, It does not default to defrost.

I used the hillbilly method to test the line at the valve... suck like hell then see if it will stick suck to my tongue. Gross I know, but got to do what you got to do sometimes. Nothing... I would say as free as sucking through a coffee straw. What should I do next?

KyleF

Not your normal issue, no hiss and the selector works fine. All positions function. I was flushing the sytem because the previous owner had put dexcool in the system. Durint he drive to "flush" the system, when I switched the heat on I discovered there was no hot air. After cool down I found there was still "red" coolant in the lines going to the heater core but very green in the radiator. This told me the heater control valve was not functioning properly. Checked the vacuum line and couldn't hold a vacuum on it. Traced the lines and found no issues and no leaking hiss sounds. So, I removed the valve and bench tested it, it didn't shift. $20 and a trip to the parts store later, the IROC has heat. The new valve bench tested fine.