I work for a company that basically spends 0 dollars on anything for upkeep, regardless of what piece of equipment it is. Repairs are often layout string and duct tape, maybe WD-40 if we are lucky. We work road construction and it gets really hot in the summer on this new hot asphalt here in Florida. So you can see where this is going. The bosses when they were younger, used to sabotage the A/C systems, because they were under the erroneous impression that nobody would get out of the truck and work. Now they occasionally get the air fixed, because the new company they sold to, takes heat casualty a little more serious. Yet some of the trucks they still won't.

I don't know much about how A/C systems work but I intend to become skilled at it. Two current trucks I frequently ride in have the following problems.

2013 F150 - The A/C actually works, it does get cold. The blower appears to work, the problem is lack of air flow, only a little bit of air comes out. There is some air flow on start up but no long later its minimal, was doing the same thing last summer, looked for paper or bag obstruction behind glove compartment, and looked to see if the flapper under the hood was obstructed, niether are. What research I've done suggests it may be in the vacume system or something to do with recirculator door, I cant find it. Any help appreciated in advance !

Truck 2 , dont know the year but similar age F250 Super Duty. Crazy problem, The A/C works when you first start it up, and as long as you leave the truck running all day, it has great A/C. But shut the truck off and your screwed. It will eventually go back to working again after 20 min to an hour, but same rule applies, if you shut if off again, it quits working again. This truck uses an insane amount of gas. The bosses come around to provide unnecessary supervision, and always harp about " why the trucks are running?"
The rest of the trucks we just shut them off when we see them coming, but this one we have managed to come up with a multitude of lies, depending whether or not we happen to be sitting in it. Fools don't realize that if they would fix it, we wouldn't leave it running, burning all that gas. So any help I can get for this phenomena would also be highly appreciated !

 

Reach under dash glove box area near kick panel and find the harness connector for the blower resistor. Wiggle it and see if the fan speed starts or changes rpm. Remove the connector and check for a burnt loose pin. Harness plug and resistor may need to be changed.
As far as I know 2013's don't have a cabin air filter but that doesn't mean the evaporator fins may be blocked with lint being a work truck. You may need to pull the blower motor and check evaporator fins with a mirror.

 

A couple good tips there, as I said though The blower roars at full speed, possibly the squirrel fan not spinning. 13's do not have a filter, but I didn't know I could check evap fins that way. I do not believe this is an electrical issue, I believe its airflow restriction of some kind, just where would something get in and plug the system?

 

The blower motor intake is at foot level on the pass side. They suck in plenty of dirt.

 

I was thinking truck 2 might have the resistor problem if by A/C not working you meant the fan not blowing.

If you pull the cabin filter out of some vehicles there are all sorts of debris caught in it. If no filter, that debris can gather on the evaporator.

 

For truck #1, check for a dirty evaporator as already mentioned. Pretty common for trucks used in construction or farming where operation in a dusty, dirty environment is common.

For truck #2, check the compressor clutch gap for excessive wear. When they wear, they get weaker and tend to fail after they warm up. If you pop the hood and look at it when it's not cooling, you will be able to see if the clutch is engaged or not. If not, safely tap it with a stick or tool and see if it snaps in. If so, perform a shimectomy.

 

Truck 1 : Makes sense to me, does this require dash dissassembly, or is there a more field expedient way to do this with say, a vacume or an air compressor ?

Truck 2: This truck has done this for the entire 3 1/2 years that I have been with the company. Your solution makes sense to me. Again is there a more field expedient method like giving it a hit of WD 40 or John Deere bar and chain lube? Can the clutch itself be replaced in say, an hours time? What is a shimectomy?

 

Truck 1: Pull the blower motor and inspect.

Truck 2: Use a stick or screwdriver handle. You have to first confirm (or reject) the hypothesis before going any further.

 

You've been given some great layperson checks.
If I may add one bit, when checking the compressor clutch operation - check for activation(clicking), check for engagement (spinning center)

 

Would it work to take a cell phone with flash activated and stick it up in there and snap some photo's in place of mirror?

 

Thanks all, Great tips no doubt ! Please understand that I have to do this while working . Sometimes we have a lot of idle time, and sometimes a little, and often none, so I can only do so much at a time. I have to do this in increments.
If I pull the blower, I could probably snap some cell phone pics up in there. Would that maybe work?
Also If I take the blower out, and take an air compressor hose with air blaster, ( we always tote one around ) And blast air up in there, Will it ? A. If I point it the right way, blow air through the ducts letting me know they are clear ? And B, if I point it in the right direction, blow the dirt back out of the evaporator ? C. Or do I have to take the whole ( expletive ) dash out to clean it?

 

why do you need cell phone photos.... ONE truck has the air ducts plugged... the other needs 2 minutes of LOOK to see if the compressor is TURNING or not when the clutch is engaged ( assuming it is, as you said).

 

A previous poster stated to use a mirror and look to see if its clogged up. Since I am not in the habit of lugging a "mirror" around while I'm working, I was wondering if I could take a photo instead and still see what I'm looking for. Since you want to be smart about it, how about you read up as I was mostly reffering to checking to see if the evaporator fins were plugged up ! The other truck I haven't been using lately so I haven't had opportunity to look at that one yet.

 

Use anything you can to grab a view, camera should work just fine. I used that method to grab a pic of my rear axle id tag to save for future use. Couldn't get my big head between the bottom of the bed and top of the axle where it's at to read it so I held my cell phone about where I thought it would get the pic.

 

Thank You for providing some sanity !