I recently had some issues with a faulty IDM, and fixed that. Although, right before that issue, I was traveling back home on a 3.5 hour drive and halfway through the trip we stopped at a store.

I never shut the truck off as usual, but when returning onto the highway, I noticed that the A/C wasn't blowing as cold as it normally does. After a few minutes of gaining speed, it then began to get cold and perform as it normally did. I generally run it on the "Max A/C" setting, since I was always told that it would recirculate the cold air already in the cab, and it would operate more efficiently. Which now, when on this setting, I am noticing that outside fumes and smells are entering the cab.

Since, I was dealing with the IDM issues, I didn't really notice any changes in the A/C's performance until now. It only seems to perform better and colder when at highway speeds. I also noticed that there's more condensation dripping than usual, but thought this may be due to tearing some of the foil/insulation when I removed the left valve cover to replace the glow plugs before I realized it was an IDM issue I was dealing with previously.

One other thing I noticed recently with this A/C issue was that when the A/C is "Off", there is air flowing from the vent to the floor inside the cab.

My apologies if this is confusing, but I'm confused as to what the issue or issues may be here with the A/C not functioning properly.

If anyone has some advice or comments, I'm all ears and totally appreciative!

In case it's not on my profile. 1996 Ford F-250 7.3l Powerstroke Diesel Automatic

Thank you in advance!

KLondon

 

if they are your fumes, the you have an exhaust leak and shouldn't use max air until fixed


plug a leaf blower in ex pipe and spray every joint and flange with soapy water. any bubbles found is a leak you need to fix.


maybe you broke/cracked the vacuum line when working on the pass VC

 

I appreciate the input. I'll look into that for sure!

 

I was just watching a video on YouTube, and they state that the A/C clutch could be the issue when it becomes worn out. Since it will only perform properly when at higher RPM's.

Anyone have any thoughts on this as to it being my issue?

 

A very common problem on this generation F150/250/350 & Bronco is found under the hood over on the passenger side. Look on top of the heater blower housing. There is a vacuum motor, that works a small bellcrank to open/close the Fresh Air/Recirculate door (the recirc door itself is just above the passenger's feet, easy to see it down there when inside the cabin).

The vacuum motor has a White vacuum hardline on it, that goes into a harness, that goes through the firewall to the climate control head. Take a good look at that vac line under the hood. It may still be White, or it may have turned color to filthy white, beige, brown, etc.

For some reason, that one vac hardline crumbles with age. Not only does it crumble where it is exposed, it seems to crumble a ways into the harness too, so if it's crumbly exposed, open up the harness to get back to good plastic hardline. Can fix it by getting some small diameter vac hose to slip over the good plastic hardline on the harness end, and onto the vac motor on the other end.

Should restore proper action to the Fresh Air/Recirculate door, and should restore full vacuum to the control panel again (vac leak gone).

 

Thank you for the advice and instructions. I'll be checking it out at first light, and I'll update accordingly.

 

That vac line referred too gets rubbed by the hood hinge and wears a hole in it.

 

THANK YOU! THANK YOU! THANK YOU!!! You ROCK Torky2!

I traced down the crumbling hardline, and spliced in a new piece of durable vacuum hose. My A/C has never works so darn well!

I really appreciate it!

 

Heeeyyyyy this might by why my ac doesn't work well too! Thanks Bryan!!!

 

While we are on the subject, there is no difference between my max and regular ac. Probably the blend door, anybody know how to fix that?

 

Glad that was it. We still need our A/C here in Texas!

 

Do you mean that it is cold both ways, can't adjust it warmer with the temperature slider?

Or do you mean that MAX doesn't get any colder then regular?

If it's the second one:
With the fan speed up a few notches, switching from the regular A/C position to MAX should result in an increase in fan noise, because with the recirc door open in MAX, sound now has a short path from the blower down through the open recirc door to the cabin.
With the recirc door closed to the cabin in regular A/C, sound had to make it from the blower, through the A/C evaporator, then through the narrow supply ducts, which quiets it down like a muffler.

With it in MAX and engine running, I'd also look under the dash by passenger's feet, and see if the recirc door is open. It's obvious if it is, and the blower motor will be whining out the open cabin intake port.

 

Yeah, max isn't any colder and I don't notice a change in sound. I'll have to check that out, Thanks!

 

Yeah, no kidding! I'm ready for some cooler weather in Texas!

Thanks again bud!

 

Glen, take the 6-8 screws out of the cover on the front of the heater box , and check to see if anything fell down the defroster tubes. The previous owner may have stored pencils or something similar on the dash. They will migrate down the tubes and block the blend door.