Classic Winnebagos & Vintage RVs!

Topic Boards => Chevy - GMC Chassis => Topic started by: 22Chieftain on June 25, 2022, 10:37 PM

Title: Cab air vent Actuator question
Post by: 22Chieftain on June 25, 2022, 10:37 PM
 New to the forum, first post. I recently picked up an '88 Chieftain, p30 chasis, 454 carbureted engine, 22'er. Okay, I've noticed that the vent selector is not working and air only blows from the defrost. There are two vacuum canisters under the hood. One for cruise control and the other for HVAC. There is one hose missing from each and I'm not sure where they come from or go to 🤔. Air blowing from defrost with A/C selected is cold, but it would be very nice if it would blow from the vents, lol. I have two questions: Where should I start? And is it possible to just bypass the vacuum operated actuator and just set it to blow from the vents manually? Thanks in advance for any help.
Title: Re: Cab air vent Actuator question
Post by: 22Chieftain on June 27, 2022, 09:07 AM
Can anyone at least point me to the location of the plate/door that directs the air flow?
Title: Re: Cab air vent Actuator question
Post by: eXodus on June 30, 2022, 05:27 AM
search for vacuum diagram in all the forums.

The issue is that - we don't know how built your A/C unit. There had been different manufacturers over the years.
One of those tanks is connected to the engine the other to the A/C control selector box.

All the actuators for the HVAC system should either under the passenger side dash - or under the hood on the passenger side.  (look up and left)
Title: Re: Cab air vent Actuator question
Post by: Mlw on June 30, 2022, 11:10 AM
Probably the cable of your selector is broken if it's mechanical so I would start from the controlunit. When it's electrical there can be more problems, like fuses, defective electrical units etc.

That really doesn't matter for finding your blowerbox because you will have a mechanical or electrical wire running from your controlunit to your blowerbox.

second way is  to try to find your airblower motor. This is build on the blowerbox that sends the air to your selected airvents turn your contact on, and try to locate the sound.