a/c questions
 

on my 75' 1/2 ton big block,

blower motor was only working on HI

i replaced the blower resistor, then found out my ac relay on the ac box was bad. (relay working now)

the blower fan speeds work correctly in all ranges (bi-level, defrost, heater, vent etc)

when i have the selector in MAX AC, the blower motor only works on HI speed...

is this normal?

I thought the speed would have been adjustable...

Input please....

Re: a/c questions
 

anyone with factory ac?

Re: a/c questions
 

anyone with an a/c wiring diagram for a 75?

Re: a/c questions
 

Max a/c just routes air from inside cab and not outside, basically recirculating cab air that is already cooled. Hi speed will be the same either a/c or max a/c. Is it only on max a/c that you cant get med or low fan?

Re: a/c questions
 

yes, only on max ac...

on max ac i only have hi speed...

on all other settings, i have all blower speeds....

never ran into this problem before...

Re: a/c questions
 

As far as I know there should be no interconnection between the two since vacum control is the only change when going to max a/c. I will check my service manuals in the am and try and get you a diagram of the wiring.

Re: a/c questions
 

These are from my 74 gmc service manual. Let me know if you need any closer pics. Good luck

Re: a/c questions
 

thanks for the info... now i have to read it all!!!!!