Cab A/C not blowing correctly

ruralIN · 02-03-2022, 06:17 PM

2002 Ford E450 chassis. Coming South the heat appeared to work correctly (defrost, mix, floor) but when we went to A/C side the blower stayed predominantly on defrost and A/C didn't work as well as I thought it should like heat didn't shut off. I checked the fuse the driver's manual said controls this action and fuse tested good. Any ideas?

RogerR · 02-03-2022, 06:30 PM

Yours is old enough you probably uses engine vacuum to pull the doors that direct air to different positions. If you can, check the engine bay for a fine hard plastic pipe, maybe 1/4 inch leading to an air intake or somewhere from the fire well. You may have to get help but you possible could hear the hiss of a broken or cracked line.

A good mechanic can put a vacuum pump on the proper line and find the leak.

alternatively, the knob could be bad that controls the vacuum.
Some newer vehicles have electric doors, not sure if which you have.

ruralIN · 02-04-2022, 10:23 AM

Thanks for your reply. I looked this a.m. but was unable to see lines that I could identify as potential problem or hear anything. I did however note that the compressor was short cycling which I believe could be either low on freon or obstructed airway. The lines did get cold even with the short cycling. Since I am not too keen on tearing into the doghouse or breaking camp for the next several weeks, I guess I'm going to wait and see what the weather brings when we head North. We have seen years where that is a heating situation or I can run the generator and use the house A/C if needed. Get it taken care of in the spring unless someone has other thoughts. Input appreciated.

bucko · 02-04-2022, 11:32 AM

Just be sure to not add freon from the auto stores. 90% contain a "sealer" that is advertised as sealing small leaks. They don't work! Dealers and A/C shops won't touch your vehicle after this, as it can ruin their evac systems that claim the freon prior to working on it.

So, unless you want to add your own freon every 2 to 3 weeks, get it serviced by an A/C shop.

RogerR · 02-04-2022, 02:08 PM

On your possible vacuum leak try calling the dealer for your chassis, Ford?, and asking where the vacuum supply hose is. Tell them you are camping and if its just a leak you would like to make a temp fix to get home. They may be willing and able to tell you where to look or tell you if it is electronic instead of vacuum.

If you get that info then see if there is an Autozone, or other autoparts store nearby that you can borrow a vacuum tool the will let you see if you can find the leak. Alternative is to blow smoke into the pipe but that is probably not a loaner.

craigav · 02-04-2022, 02:49 PM

I would suggest to review these youtubes. What you described is not all that uncommon and in fact mine just did this as well and I ordered all the parts needed from amazon, but I haven't installed them yet. ~CA

https://www.youtube.com/watch?v=tZA9...dTY7grYwNw0Axa

https://www.youtube.com/watch?v=O-Wo...dTY7grYwNw0Axa

https://www.youtube.com/watch?v=ddcZ...dTY7grYwNw0Axa

ruralIN · 02-06-2022, 03:10 PM

Thank you for the YouTube references. Looks very promising. I'll probably wait until I get home to tear into that repair but it looks like the sure problem.

ruralIN · 03-16-2022, 04:22 PM

Since the temps have been above normal down here and the price of gas is up over a $ since the trip South, I decided to do a temporary fix while here. Cost of parts was likely less than the cost of running the generator 2 - 3 days while traveling North to cool with the house A/C. Used the best practices from the videos referred and others I found. Will make it more permanent when we get back home.

craigav · 03-16-2022, 06:09 PM

Just curious, did you simply run a vacuum line? That works and also helps you keep off of the throttle a bit.

~CA

ruralIN · 03-16-2022, 07:16 PM

No, I got a vacuum reservoir and the valve also. Ran a line to the valve and put reservoir on top of the battery, for now, and ran the vacuum line between the fenders. Took out a plug, drilled a hole through it for the line to get inside the cab and spliced the line inside. No doghouse removal,etc. Plan on removing the fender once home and hope to find a place to mount the reservoir onto the inner fender near the turn signal. I am curious how performance may improve without the vacuum leak.

ruralIN · 05-10-2022, 07:42 PM

Now that it is complete, you can see what I did to fix the problem.
https://youtu.be/ac_LhnZnVOQ

bucko · 05-11-2022, 03:31 AM

That was an enjoyable day! Thanks for the video and solution. This should help others in the future.

foglght · 05-11-2022, 01:36 PM

Quote:

Originally Posted by RogerR

Yours is old enough you probably uses engine vacuum to pull the doors that direct air to different positions. If you can, check the engine bay for a fine hard plastic pipe, maybe 1/4 inch leading to an air intake or somewhere from the fire well. You may have to get help but you possible could hear the hiss of a broken or cracked line.

A good mechanic can put a vacuum pump on the proper line and find the leak.

alternatively, the knob could be bad that controls the vacuum.
Some newer vehicles have electric doors, not sure if which you have.

2021 motorhome still uses the vacuum lines.

but yes, check the vacuum connections to start. It's probably a blend door issue.

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