A/C mod?

[Spartan]

This potential mod is for a 2014 Sierra, and I have a question for the electrical minded modders. Hopefully this is in the correct section.

 

Is it best practice to power an actuator by connecting it to another circuit so they operate together?

I want to install a bypass valve in the heater core hoses so when the recirculate HVAC button is pushed, the coolant flow by-passes the heater core. I’m 99% certain the coolant has constant flow through the heater core and I’m almost positive that this mod will drop the AC temp by a few degrees.

I’ve found a vacuum actuated valve that’s driven by a small electric vacuum pump. Connecting the pump to power up with the recirculation button is the only way I can figure out how to do it.

What do y’all think?

[spectaculous]

i think the GM engineers that designed this HVAC system knew what they were doing when it came to the controls. this system gets COLD when you tell it to (at least the climate controlled one does). is yours not getting cold enough for you? there is a setting somewhere on mine that you can change the auto fan speed. if you have that setting, make sure yours is on HIGH.

[Spartan]

No. My system does not get cold enough for me. There is no such thing as "to cold" of an A/C for me during the months that are so hot you can feel your face cracking walking through the parking lot leaving work. Right now my A/C only blows down to the high 40's. The last vehicle i did this mod on would blow between 39 & 42 degrees F.

 

This valve used to be a standard feature on a lot of GM vehicles until about 1999 or 2000.

 

I'm just trying to make my truck the way the GM engineering "didn't" make it.... better. Lol.

[spectaculous]

You might need to recharge your refrigerant. Or your temp mix valve is not on full cool, as these HVAC systems should be as cold as any others out there running the newer refrigerants. I don't think you need to do any mods to make it right. You just need to fix what is causing your lack of cooling...

[txab]

Why not test your theory by blocking the flow through the lines while observing vent temps. I think you're going at this ass backwards though

[waumo1]

The only time you might really need it is in the dead of summer so put a manual switch on it.

And yes all the GM cars I owned in the late 60s had a heater core block valve and those air conditioners were POA units that put out a hell of lot more cooling than any of today's units. When I fire up my 69 Grand Prix in the summer, it becomes clear how sorry today's A/C units are.

[jamin87ss]

Mine doesn't either, not hot or cold enough, and the defrost blows literally

[O_J_Simpson]

You are asking an auto climate control system to match the AC performance to an old school manual system. It won't happen. Modern auto climate control systems mix air with cooled air coming off the evaporator coil while old school manual systems did not. You have to do it yourself via the blend option knob. Try as you may, you will not get to the magic number of 38-40F with an auto climate control system you can get with a manual system. Programming won't let it happen. If you wanted truly ice cold air, you need to buy a manual AC truck. Vent discharge temps don't lie.

[txchevy4ever]

No. My system does not get cold enough for me. There is no such thing as "to cold" of an A/C for me during the months that are so hot you can feel your face cracking walking through the parking lot leaving work. Right now my A/C only blows down to the high 40's. The last vehicle i did this mod on would blow between 39 & 42 degrees F.

 

This valve used to be a standard feature on a lot of GM vehicles until about 1999 or 2000.

 

I'm just trying to make my truck the way the GM engineering "didn't" make it.... better. Lol.

You may mean too cold.

[SouthernSilveradoGuy85]

On the really hot humid days I put it on LO with the fan full blast and put all of the windows down for a little while so the A/C pushes that hot air out. I kind of think you're being too picky about it. My first truck/vehicle was an 86 Chevy C10 and guess what, didn't even have factory A/C at all. My A/C was the vent windows in front of the door windows.

[redwngr]

On the really hot humid days I put it on LO with the fan full blast and put all of the windows down for a little while so the A/C pushes that hot air out. I kind of think you're being too picky about it. My first truck/vehicle was an 86 Chevy C10 and guess what, didn't even have factory A/C at all. My A/C was the vent windows in front of the door windows.

It had '4-60' air!