I have a 1998 grand cherokee laredo 4.0, with 160k on the clock.

When I first bought the jeep, i was told the ac didn't work at all. The a/c pulley wouldn't engage. I did the paper clip trick to recharge it, and it was doing ok for a couple years (not ice cold, but at least it was something).

The past few months it has pretty much stopped blowing completely, with the occasional cold air/warm air coming through very randomly.

After some reading, I figured it was either the blower motor or the blend door actuator. I took out the blower motor and felt up the blend door, and it is very floppy. I.E. I can move it freely without resistance and when let go it falls back down.

Now I dont know which way the blend door is supposed to rest, so I jammed a screw by the door to keep it up, thinking maybe this will allow the air flow (sometimes you can feel cold air at the vent, but it doesn't come out with any oomph, as if the door was stuck in the way of the flow)

Wedging the blend door did nothing so I bought an actuator and low pressure sensor.

I installed the sensor first because its much easier than getting to the actuators screws, and still nothing.

Now it is worth noting, I removed the head unit (manual) because it makes a vacuum leak noise when the air flow **** is moved. I took the thing apart to check it all out, it looked pretty good. So i figure the vacuum harness thing that connects to the back is the culprit since that is where the air flow leaking noise is coming from.

I just put the head unit back in, and no the a/c button refused to stay depressed, and there is literally no air flow to speak of from anything.

Any ideas? New head unit? Did I assemble the head unit wrong? Could the vacuum harness be the problem? Is a vacuum harness even a thing?

Thanks