Omarsvette

i currently have the interior apart in my 73 restoration and i wanna make sure the a/c works before i assemble the center console or passenger apron. can the vacuum duct be tested without the a/c compressor connected? how can i tell the controls for the a/c will work? can the defrost be tested? what about the heater? the blower motor works but shuts off when i move the other controls.

billschroeder5842

My thought is that you will spend more time and money just trying to rig a temporary system to test the AC than you would by just installing it to specs?

You can test the individual components out of the car (vacuum actuators) with a hand vacuum pump. The heater blower can be tested, the heater core can be tested and water shut off valve can be tested out of the car.

I'd just test the individual pieces and then assemble.

Omarsvette

Headlight vacuum works. So does the blower motor. My concern is the climate control that works of vacuum. How can I tell those work? Just starting the car and playing with the *** while the blower is on?

billschroeder5842

Not sure on a 73, but my 82 would require that the vacuum system be hooked up to test each zone.

You could take it out of he car and use the hand vacuum to test as you spin the dial?

Omarsvette

That's pretty much what I just did. Seems all works well. I then starter the car and connected my controls. I had my ac valve backwards. Easy fix. Now they work good except my kick panel door doesn't close. But I was thinking of just keep it open and shutting the outer door to have max ac. Do you think it would affect my other settings.

7T1vette

The rest of the system doesn't care whether the A/C is working or not. You can just disconnect the electric clutch on the A/C, then test the rest of the system.

The Chevrolet Chassis Service Manual (CCSM) is the manual you really need to know how the electrical and vacuum systems operate (what switches work, and when; different A/C-heater settings vs. damper actuations; etc). There are activation switches on the side of the control head and these must work properly...and be 'timed' properly...for everything to work right. All can be checked out before buttoning the interior back up--as long as the connections can be made ahead of install.

You definitely want to do this, even if you have tested all the components. You can have 'good' components, but they may not actuate right when connected (linkages, seals, etc). Now is the time to determine that; then fixes can be made prior to final assembly. Your 'instincts' were giving you good advice to ask about this prior to button-up.

Omarsvette

Is the shop manual the same as ccsm? I have the AIM and shop manual. They help tremendous but sometimes I need it explained. Like the thermal switch and the high speed switch. Lol thanks to the Internet! As of now my connections are good. Looking at my manuals I found out that there is a fuse from ac relay to horn junction box. Previous owner cut it of along with the safety thermal switch to the compressor. I don't have freon yet. My concern is the blower. It works but cuts off once I move either rotary switch. According to the manual, the blower cuts off if the there is a open circuit in the system. Is this correct?

carriljc

I got mine at harbor freight for some good price (don't remember). It really comes in handy for testing vacuum actuated systems. AND also for evacuating the a/c system for future recharging.

Omarsvette

That's were I got mine. So valuable.

Also, my dad has a 74 service manual. He forgot he even had it. It should be the same for 73. Y'all think it would work?

7T1vette

Not sure what you mean by "shop manual". There are several shop manuals produced by non-GM sources. But, only the CCSM is produced for General Motors and only that one has the detailed info you need on the heater-A/C system.

There are actually two Chevrolet Chassis Manuals: one is the Chassis Service Manual; the other is the Chassis Overhaul Manual. If you wish to rebuild any of the original components of your vehicle (engine, trans, diff, starter, A/C compressor, power steering items, alternator, etc), you also want the Overhaul Manual. The CCOM is out of print and is best found on eBay on occasion.