husky_wolf

Alright guys, just got back from Alaska today. Had my ac on high cold seeing as it was a very hot day in az. As I was getting onto the freeway I stepped on the gas to accelerate and the air pressure coming out of the vents dropped significantly. As soon as I let off the pedal it went back to normal. I did this a few times just to make sure it wasn't a fluke and it had the same results. Any ideas what the cause could be?

djb383

Vacuum leak....start by looking at the football behind the front bumper and work your way back to the dash controls.

husky_wolf

I checked for a vacuum leak in that area didn't hear anything. Although I did hear a small leak coming from around the tb couldn't narrow it down though... Wouldn't a vacuum leak there Cause the AC loss of air? Sorry a slight noob

md21722

The dash vent actuators are vacuum controlled. Check the intake manifold. There are 5 vacuum connections- 2 on top, 3 on the side. The elbows on the side connections tend to fail. Just be careful moving things ago. The lines can be brittle and break.

husky_wolf

Do you have a good diagram of the vacuum line system by chance?

md21722

I have the FSM but I believe forum rules & copyright laws prevent me from posting. It should be pretty clear by looking at the manifold. There isn't anything hidden underneath. What isn't fuel, electrical, or the air intake is vacuum.

husky_wolf

I thought so, I only saw one line on the side and three lines on top.. Still couldn't track down the leak, would there be anything else that would cause the original problem?

Pelican

Your A/C problem is almost certainly lack of vacuum. When you accelerate, engine vacuum decreases and A/C vents default to the defrost position.

I wouldn't depend on hearing the leak(s) but then I'm deaf to start with (per my wife). Perhaps the most common point for cracked vacuum line is in the battery area where acidic fumes work on the plastic line. Assuming that you have a decent vacuum at the reservoir (football) , I don't think you need to worry about leaks elsewhere affecting the A/C system.

Of course there can be a leak inside the cabin causing the problem but most seem to be in the line from the reservoir to the firewall.

RTorrez1

I would start at the vacuum ball under the front bumper passenger side and fallow the hoses all the way back to the fire wall. Don't forget to check the vacuum ball itself for any cracks.

husky_wolf

Ok guys, so I replaced the vacuum line coming from the reservoir to a t fitting by the battery as it did have a crack in the line. But, still on hard acceleration my air is still defaulting to defrost. Should my next step be replacing the actual vacuum reservoir or is this a normal thing? Help!

RTorrez1

No it isn't normal. Before you by a new vacuum ball check it for any crack. They are plastic and can crack.

husky_wolf

So I went back to see if I over looked any of the lines and sure enough the line going into the fire wall on the passenger side had a nice crack! Now how the heck to do get that line out??? Do I have to take the while dashboard apart? I tried tugging on it and to my luck, the line broke completely... Today is just not my day lol Anyone know how to get this line out?

CCKen

If there is any tube left on the front side of the firewall, use a small section of rubber hose to join the two plastic tube halfs together. O'reiily Auto Parts sells the small ID rubber hose.

You won't have much luck getting that tube out and fishing new tube in.

CCKen

HVAC tube fix:

husky_wolf

Fml.. so I'm assuming I do have to take apart most of dashboard to get new line in there lol