Low vacuum warning switch: needed for HVAC?

[Danielle]

Mine finally rotted apart at the vacuum port.

For HVAC, does this now need to be plugged off, does it need to be working?

I've smoke tested all lines and repaired and replaced any broken, and vacuum pump producing about 18 at idle. I think spec is 20 so not too far off?

But I'm stuck at defrost, so not sure if I should plug this port or it needs to be functional?

 

[Nero]

The vacuum switch thats bolted to the passenger fender liner is not required to make the HVAC work.
There's two styles of HVAC controls, mechanical linkage and vacuum operated one. If its stuck on defrost I assume you have the vacuum one. You'll have to verify you are still getting vacuum at the head unit in the dash.

 

[hacked89]

Off the top of my head the vacuum was just for the blend door and the rest was mechanical driven. You can move the blend door by hand. I don’t pay too close attention to this area of this gen trucks because on my projects I delete a/c and just run defrost.

 

[Clb]

Plug the port off nearest the source, and forget it...

 

[snicklas]

It doesn’t need to work for the HVAC to work… but the HVAC needs to have a leak free vacuum system to work… So I’m with CLB, plug it at the “splitter” on the firewall and move on.

 

[Danielle]

Thanks everyone!