Climate control

[Sleeperatidle]

Looking to see my options and what you may have come across. A/c and heat works great but a few issues I want to fix before it gets cold again, vents blow thru dash and floor not at the windshield when turned to defrost. Is that a simple blender door issue? Can I make the flap move manually under the dash or will I have to take the dash out?

Another question. Blower only blows on high, what’s some common failures on why it does that? I don’t know where to start and don’t want to throw money at it getting it working if I don’t need to. Thanks for your input.

 

[dyeager535]

I can't recall how the AC setups are wired exactly as they have a relay for blower control, but would seemingly be a resistor or connector issue. GM was a little skimpy on the wire/connectors this vintage, it's fairly common for the connectors to melt.

Since it still works on "direct" 12v (high speed is 12v, not run through a resistor like the other speeds) I doubt the dash switch has failed, and the circuit is obviously getting power so it's not the power feed. That leaves everything after the switch. Should be able to backtrack from the heater/AC housing to find the wiring, relay pack, etc.

 

[Sleeperatidle]

I can't recall how the AC setups are wired exactly as they have a relay for blower control, but would seemingly be a resistor or connector issue. GM was a little skimpy on the wire/connectors this vintage, it's fairly common for the connectors to melt.

Since it still works on "direct" 12v (high speed is 12v, not run through a resistor like the other speeds) I doubt the dash switch has failed, and the circuit is obviously getting power so it's not the power feed. That leaves everything after the switch. Should be able to backtrack from the heater/AC housing to find the wiring, relay pack, etc.

Thank you, do you know where is a schematic for wiring?

 

[Wes Harden]

Hi blower skips the relay, so I would check the relay first. Relay is located under hood on evap housing blower motor side. The fan switch requires the instrument panel removal to get to.
Here is a hvac diagram

The system should default to defroster vents if there is a loss of vacuum. I am thinking that there is a door issue.

well I can't get the attachment to up load gets to 99% and stops I'll try something else

 

[Wes Harden]

had to edit and save to get it to work weird

 

[Sleeperatidle]

Thank you! Really thank you lol. I will piddle with it when I get some free time not working.

 

[Wes Harden]

btw thats vacuum not electrical diagram