94 GT 5.0 only blows on HIGH

Ok, so I figured out the 5.0 runs off vacuum for the heat and ac, at first I was only getting ac and heat through the defrost vents, now that I fixed that tiny plastic line and plugged it back into the rubber AC vacuum line coming from the tree I’m only getting HIGH as a option. I have no low, or medium. I noticed a few other vacuum lines blocked off, think it’s the one that went to purge. Rest of the tree is hooked up. The entire cluster in the car looks brand new, so I’m not sure what’s going on, and since my Chiltons is useless, I may as well throw it out the door. Anyone have a Diag of the vacuum lines for the tree? Also what do you guys think, blend door or what? If the switch panel looks brand new I don’t suspect the high to work if low and medium aren’t. I’m lost. Anyways I thought I’d let y’all think it out. Again, before I had heat and ac but only through Defrost, then I found the tree, the small plastic line from the cab was broke off so I cleaned out the rubber cuppler, and put the small plastic line in the AC vacuum line that it came from before off the tree.

Mustang5L5 said:

Resistor pack. It’s either blown or unplugged

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Where is that at? I know it’s gotta be near the blower motor, but never worked on a blower motor in a mustang before let alone a resister pack in one. I’ve worked on them in Semis before but those were easy to find

What is these wires? They come off a loom in the passenger side. Also someone please send me a vacuum diagram so I can sort this out as well. I’ve got a few vacuum lines that need replaced and some that I need to figure out where they go. Still not sure of the location of the resister

What vacuum line runs under the manifold on the 94 5.0? It’s the one that runs to that little canister shaped piece with wires going to it? I can’t figure out where under the intake it came from because I’ve got no diagram to show me let alone what that part goes to

Lawdawg86 said:

What vacuum line runs under the manifold on the 94 5.0? It’s the one that runs to that little canister shaped piece with wires going to it? I can’t figure out where under the intake it came from because I’ve got no diagram to show me let alone what that part goes to

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I figured which one it was, the evap line. I had broken it and then had to run it back to evap check valve

Essn95 said:

Isn’t this the blower motor resistor?

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I’m thinking that too. I talked to the original owner and it was replaced with a new one about 2 months before I got it, then she let it sit.