Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

E150 A/C Vacuum Problem

We have a 2003 E-150 van with the small 8. It runs great - no rough idle, plenty of power, all that stuff. But here’s my problem: When we go up a long hill, or even a long, gentle slope on the freeway, the A/C cuts out and the air valves close. On a hot day in the desert, that’s a pain. I pretty much guessed it was a vacuum leak that was minor enough to be overcome when manifold vacuum was high, but not when the vacuum dropped. A trip to the mechanic pretty much confirmed this, but with a twist. He says that the line to the mixer valve on the dashboard is good, but when the valve (Max A/C, A/C, Vent, off, Floor, Mix, Defrost) is in some positions, the vacuum holds, and in others, the vacuum drops to zero. He says I have to pull the dash and replace the acuating solenoids one at a time until it works. That’s an expensive proposition.

My question: Is there any alternative? Can I reach the system without pulling the dash? What else could be done?

There’s something called a ‘smoke test’ they do to find a vacuum leak that would show the culprit leak. Has anyone offered to do this ?
Otherwise , take the dash trim off so as to see those vacuum motors. You can test each one manually. Take the hose off of the port, squash the arm all the way in and put your finger over the tip of the nipple. The arm should stay in if it’s holding vacuum. If it’s leaking the arm will pop right back out.
Go to your Ford dealer and ask them to print out a parts diagram or two that show where they are. They’re not a tech ‘how to’ but they’re awfully helpful in finding those parts.
The functions that don’t work is your key to which vacuum motor to check first. Also notice the condition of the tubes and hoses and listen closely as well.

Is this manual or automatic climate control?
I assume that by actuating solenoids you really mean the vacuum servos. I doubt that one of those is the trouble. (If it were, it would be easy to find, no need to replace them one by one.) It’s more likely to be the control valve on the climate control itself.
Of course, I have to question this “mechanic’s” abilities if he really said that the servos would have to be replaced one by one to find a bad one.
I think you need to find a shop that specializes in AC repair, and not some chain shop.