2000 E350, only defrost vents work

I should add, it requires Evacuating and Recharging the A/C, AND Draining and Refilling the Cooling System.

A trained man said it takes him a day to replace A/C Evap Coil in a Mustang. E-Series similar.

To bypass it? Well south of $40 in parts. No more than an hour's work.

pnichols wrote:
Isn't 15 hours labor around $1500 or more?

If a Dealer wants to fix the problem with everything in its original configuration, the Dashboard, Instrument Panel, HVAC Cabinet, all have to come out. The Vacuum Tank and Check Valve are both buried in the Cabinet.

I read a number of threads about this when our controls went out in 2015, and the dealer repair estimates were around $1000. Which is why I like the fix I did or one very similar to it. It's apparently a common Ford problem, at least in trucks.

I looked up some of the Ford Vacuum Tanks. They are contorted, flat things. Unsuited for vacuum, that wants to flex and flatten the tank. That promotes cracking. Look at Deep Dive Vehicles. They're all Spherical.

This is the Dorman 47076 tank with Internal Check Valve.


Here's 47077. Internal Check Valve. One end to Engine, one to Controls.

It's the one I used, with a Dorman 47150 Check Valve. The single end is From Engine Source. The two angled ends are for Control and Tank.

Home Skillet wrote:
The repair pays 15hrs, since the A/C case has to be removed.

Holy Cow ... did you mean 1.5 hours labor instead of 15 hours labor to fix the vacuum problem??

Isn't 15 hours labor around $1500 or more?

If it was mine, I'd go get a package of "wiper/vacuum hose" then cut out what I saw to be bad and replace with the new hose. Use the whole length even if it's a short run. Then if it works, trim the length to fit and call it a WIN.

Yes you can rerun the line. That's what many of us have done. You can get between the passenger side fender well and its liner. From there you can get to the passenger side door post. Take out the plastic kick panel, and you'll see where the Antenna Cable goes through. There's another grommet near there. You can poke a hole in it for your new hose. Probably have to take the grommet out first then reinstall with hose in place.

If you connect from your broken tube, to where I show the cut in the picture, you'll have engine vacuum direct to the controls. So as I explained above, it'll change modes, but divert to Defrost on acceleration or pulling a hill.

There's a Knee Pad in front of the passenger seat. Plastic cover over a steel stiffener. There "might" be room for a vacuum tank in that space. I kinda doubt it, but might be worth a check. If it doesn't fit, you could try a check valve under the hood, or at the connection inside. Might be enough to satisfy you.

I put our tank under the hood. Wasn't all that hard to do since I found a couple brackets that weren't doing anything.

Here's where the tank mounted to existing brackets


And here's the connection where RED from Engine met BLACK to HVAC


RED is from Engine. Black with Black ZIP Tie is to the line that's broken in yours. The third hose is back to the Vacuum Tank. Marked ACME in honor of the Bomb Wiley Coyote orders to try and capture Road Runner. There's actually an artist's rendering of this bomb in a display case at an art museum in Santa Fe NM...

Thanks guys.

Seems I have found what I believe to be the problem. After the black line leaves the red connecter, headed toward the passenger side, it appears that line has been chewed off about 2.5 feet farther on. I know that, because with no pressure it pulled right out, and I can see the cut. Not sure where to go from here. Plan to take it in to our trusted mechanic and see what he says.

Suggestions are always appreciated. Can I just rerun the line somehow?

@Home Skillet... I wonder if Ford rearranged things a little. On ours, the connector to the RED tube from the engine, on to the BLACK that disappears into the HVAC cabinet, is between Battery and Air Filter, close to Oil Filler Cap. Then black disappears into HVAC not far to the passenger side from there.

It's VERY likely to NOT be the Control Head in the Dash. I wasted DAYS getting in there and found Zero Vaccuum feeding it. That's why I suggest simply cutting the black tube where I pictured.

The Very Least it Needs is Engine Vacuum to the Control Head. Some have simply found the source and then run vacuum hose to a place feeding the Head. It'll work maybe 80-pct of the time. It'll fall back to Defrost accelerating or climbing. A Check Valve will probably keep it where you've set it, as long as you're driving. If you want full function, settings holding and ability to change modes under all driving conditions, then a Reservoir too.

To repair it, you need Hose (maybe connectors) like StripIt got, then a Check Valve and a Vacuum Tank. Most auto supply stores have a spherical one. Of those, one has built-in check valve, the other does not. I chose NOT. Wanted to be able to test and replace each one individually. That paid off. Check valve failed once, and the Tank is in a harder place to get to than the Valve is.

Had the exact issue, no a/c going to the vents in the dash. Traced the black vacuum line from the top of the engine across the top vent panel to under the battery tray into the cab of the truck. Seems a mouse ate the line in 3 places. Went to Auto Zone bought a piece of line and a connector pack, $8.00. Removed the air cleaner unit, pulled out the battery and battery tray. Removed the right kick panel inside the cab and found the line. Pushed a screw driver, long one through the firewall where that line went through and taped the new line to the screw driver to pull the new line into the cab. Used the new connector to connect the line in the cab. Ran the line back under the battery tray and up to the area where the mouse ate the line and used the new connector to connect them together. Fixed, and about 45 minutes. Hope your is as easy to fix.

My 2005 E450 did the same thing.
The a/c vacuum line check valve is not working.
The repair pays 15hrs, since the A/C case has to be removed.

I checked mine with a vacuum pump. The check valve and the vacuum reservoir were bad.

I cut a hole in the right front fender well to access the vacuum hoses.
I replaced the check valve and relocated the new vacuum reservoir to the inside of the fender.Since I could not remove the OEM reservoir.
The sheet metal was pushed back into place and sealed with Eternabond.

These systems use a vacuum line from the engine. Then there's a Check Valve and a Vacuum Reserve Tank. From there to the controls. Ford chose to put the Valve and the Tank IN THERE.The problem is INSIDE the HVAC cabinet. Here's My Thread About It.

It's invasive, but the quick check is to cut the Black Tube coming out of the HVAC Cabinet in the passenger side foot well. You see it curled to a cut end in this pic. It's dead center in the pic, coming out of the black plastic, highlighted against the white firewall.

If you cut that, start the engine, and no vacuum coming from the end coming out of the plastic, the problem is as I described. Repair'll cost about $40 in parts and an hour or two's work.

Will help you any way I can.

My F350 did this. As I recall, the defrost is the default mode when vacume fails. Tried to find it, but ended up taking it to the dealer. They seemed to know how to find it and fix it, I don't remember the cost, but I remember it was less than I was bracing for.