I have a vacuum leak. That's clear. When I put the truck in 4WD the air vents to the defrost after a slow (15-20 s) transition. The only way I can get the air to come back to the dash vents is to disengage 4x4. Of course, the auto-lockers aren't working. I can trouble shoot the vacuum lines and find the leak. No big deal.

I've isolated it downstream of the vacuum reservoir. It could be the PVH solenoid but at least the reservoir side holds pressure.

My concern is the noticeably poor A/C performance. It cycles between kinda cool and kinda warm. I remember the A/C being ice cold a few weeks ago.

Could the vacuum leak in 4x4 vacuum lines be related to the A/C problems? I'm thinking blend door vacuum issues. But I can't even find the blend door vacuum lines.

How do I know if my blend door is fully open/closed?

Are there any other place to look that can cut down on my troubleshooting?

Thanks in advance,
-B

 

Once you have the vacuum leak to the hubs resolved you should see a noticeable difference. The leak may also be impacting the valve which closes flow to the heater core when the A/C is on. Trace the heater core hoses on the passenger side and you'll see the valve - check to make sure it is opening and closing depending on the mode the A/C is on.

 

I'm having almost identical issues as AggieOutlaw. Where exactly is this valve? Can you see/get to it by dropping the glovebox down, or does some of the dash need to be removed? And another question, is the blend door and the fresh air/recirc door just 2 different names for the same door, or are these 2 seperate doors? And where is it (or they) located? Thanks.

 

I too am looking for the valve and blend door. My PVH solenoid is clearly bad. I tested it and it leaks. I'm hoping that may fix this.

But I suspect my compressor is short cycling too.

Please advise if you have ideas. Thanks!

 

All check if this grey hose is connected, My AC was not very cold and blowing out the defrost until I got the rpm's up.

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