Vehicle air conditioning override

[booster]

In an old thread, recently brought up again it was mentioned that we had a disconnect switch for the van air conditioning in our 07 Chevy. Its purpose is to allow you to get fresh air, without running the AC from any of the airflow positions for the heater/ac control. We use much of the time with the AC off. Marko had mentioned it might be good as a separate discussion then, and I just ran across my notes and wiring diagram from the factory service manual for where to tap in and add the switch.



The best place to add the switch is between the heater control and the high pressure AC switch, I think, so nothing will see any signal for AC. The 14 pin connector should be accessible from inside the cab. I would not do the switch after the PCM/ECM as then the computer will thing the AC should be running and may adjust some of the engine control parameters.

[tlillard23]

I've been thinking of doing this as well. Did you figure out what connector the dash control wire goes to? Or is pulling the dash the best way to cut in to this signal?

[booster]

Originally Posted by tlillard23

I've been thinking of doing this as well. Did you figure out what connector the dash control wire goes to? Or is pulling the dash the best way to cut in to this signal?

If you open the schematic larger it has my notes of where the wires go.


I decided it was easier and better to just pull the dash off and do it there as I had to run wires to the override switch anyway on the inside of the van. IIRC getting to the wiring or connector from inside was not easy and I would have had untape the harness to splice besides. Once the dash panel was off all was quite easy and no splice under the hood to make. As explained it also keeps the signal away from other places that might think it is one and do something odd.



I think it only took a couple hours to do. I spent more time than that trying to find the right section of the poorly laid out factory service manual to get the schematic.

[tlillard23]

Booster - - I've looked for the old thread, I can't find it... Could you link it here? I remember it had some good pictures of the install and switch.

Speaking of switch, I think that's a low current circuit?

*I have my dash apart, new radio and AC disable switch are going in!!

[booster]

Originally Posted by tlillard23

Booster - - I've looked for the old thread, I can't find it... Could you link it here? I remember it had some good pictures of the install and switch.

Speaking of switch, I think that's a low current circuit?

*I have my dash apart, new radio and AC disable switch are going in!!

I think that this is the only discussion on the topic. I had to look at my first post and seems to indicate that.


Especially if you already have the dash apart, splicing in at the control will be way easier, I think, as the harness and connectors are all hard to get out and need watertight splices.


I thought I remembered it was a green wire on the control that you switch and per the wiring diagram in the first post it says it was light green, so that would be the place to put it.

[tlillard23]

Replaced the radio so I finally cut the GREEN wire and added an AC compressor switch to the dash. Took some voltage/current measurements, this is a "12volt" ~5 milli-Amp signal (spelled out for non-EE types). Just about any switch will work, I repurposed a cheap toggle switch from a car stereo setup that I used in 1991...
It sure is nice to have more than FEET OR FACE on the ventilation options without running the AC compressor all the time.

*You don't really need to drop the steering wheel and pull the whole dash, you should be able to pull the controls out with just popping the dash loose. maybe 6 screws and a handful of friction fasteners should do it.