Bob_Gallinger

Hey, new to the forum and new to fixing stuff myself.
- 1979 corvette with AC. Put in new climate controls and now can't get things working, gotta have a short or something. Car has not had controls working for at least 3 years now.
- Had the non-AC switch positions running this morning + all fan speeds working. Vacuum switches for vent controls worked too. The 2 AC positions, Max and Norm positions did not work.
- After running for 5min. I shut off and when I went back to turn on I got nothing. Hoping its a fuse, I'll look again after work.
- Blower still works (high fan speed) only if I jump the "Red" wire to "Purple" on relay harness, so Blower is good.

I had a bugger of a time to get controls working, then it worked for 5min. and now nothing again. What could it be???
What fuse? 25amp AC?
Where do I start?
I'm new/green to tinkering with cars but do know how to run a volt meter to test continuity and voltage.
After I get this running I then have to tackle the new stereo I bought, lol.

Thanks in advance for any info.
- Bob -

Bob_Gallinger

Oh ya, and I have this annoying buzzer constantly going off when the keys are in the ignition. How do I disable this???
Thank

GUSTO14

Check out posts #8 and #11 in this post by Jim Shea...
https://www.corvetteforum.com/forums...one-crazy.html

I believe this is the picture missing in post #8...


Good luck... GUSTO

TimAT

OR you could tape down the courtesy light switch or pull the fuse for a temporary disable. OR pull the buzzer.

Lakeside49

I had a similar issue and replaced most control components - but, you still need to make sure that the narrow green vacuum hose located on the firewall, under the hood, entering the vehicle above the distributor cover is not collapsed and letting vacuum flow to the control unit that you replaced. If it is soft/ collapsed your controls will be erratic , including as you describe. It is located underhood where it gets hot and is easily susceptible to failure and being overlooked as the causal.

Bob_Gallinger

- Switched out the 25amp "AC" fuse, there was a 20amp, was not in the best of shape..
- Heater control work flawlessly now, still no AC controls...
- ex.. key in "ON" position or "Running". Blower set to High, controls on heater "Vent". Blows good out proper vent.
Once I switch controls over to AC "max" or "norm" the blower stops high and goes into low "constant run"...
- What controls the AC? The relay or resistor?
- I have 12volt on both "Blue" and "Red" wires on relay.
- Where should I turn next ????
......................
Plus the buzzer is gone. Disconnected connection to the small box attached to the right side of fuse box, green and orange wires...

​​​​​​​Thanks - guys

speedreed8

I had to clean the contacts on my ac switch in my 79. There are some contacts when you put it in ac or max ac. You'll have to pull the ac control assembly to do it.

Bob_Gallinger

AC control assembly?? I just put a new one in.
http://www.corvettedepot.ca/image/ca...9constrain.jpg
​​​​​​​
Do you mean a different assembly??

Thanks for the help..

Bob_Gallinger

Anyone else ever have the blower motor turn off or run back at low constant when levers are positioned to the AC Max or Norm?
I'm going to take the relay apart tonight and see if I can clean it up.
This has got me completely stumped, and I know the answer will be very simple....

Thanks in advance.
Bob

Bob_Gallinger

Update
Relay and Resistor appear to be functioning properly.
My AC is now topped up and compressor is kicking on when switched over on the controls, just need to solve why I loose the fan speeds.
Anyone ever have this problem?

Thanks guys !!!!!

garrettb

Replacing the relay solved my issues with the speed selector. I'd try that first, they're cheap!

Bob_Gallinger

Garrett - where u having the same problem with only AC fan speeds or both AC and Heat?
My fan work perfect when on Heat, only AC is the problem.

​​​​​​​Thanks

bmotojoe

On my 77 with the slide control in A/C MAX position the fan will run at high speed only. With the slide control in A/C NORM position you should have control of your fan speed through the speed control switch.