A/C weak flow passenger side and not blowing cold

GYPSYBELLE

MEMBER
2001 JEEP GRAND CHEROKEE
4.0L
6 CYL
2WD
AUTOMATIC
190,000 MILES

Laredo, Inline 6.

So, I have noticed as the temperatures start to soar down here in the south, that my A/C isn't operating as it should.

Here is what I know: There is weak air flow on the passenger side (both center and side vents) and the air that does trickle through is warmish. The driver's side blows but not very cold. I checked the positions and it blows from defrost, front vents and lower vents as it should. When it is on re-circulation I get the best flow. (Which, I believe, rules out the vacuum lines as an issue). The flow changes as it should from low to high positions as it should (which rules out the blower motor resistor). This car did not come equipped with cabin air filters, but I haven't pulled the bevel to check if there was an aftermarket addition made before I bought the car. (I have had it 11 years).

Here is what I think may be the problem(s): Possibly the blower motor is turning the wrong way. I have researched and seen this crop up time and again that the blower motor is wired incorrectly via factory and the wires need to be reversed. Likely one of the blend doors is broken, or an actuator thereof. Possible blockage, but from where? Otherwise the car runs great aside from a squeal we cannot seem to fix (separate issue I need to address, but it's only annoying, not critical).

Anybody have this problem and fix it? I have a great mechanic but I want to try to see what I can rule out myself before I have to pay for another repair. I just dropped a crate transmission into my sweet girl, and bought a second vehicle, so I am kind of tight on funds. However, summer is pretty much here in South Texas and I cannot have an A/C issue. Oh, and a few months ago, the mechanic did a pressure/vacuum test on the compressor and recharged the system. My radiator cap had come loose and boiled dry (first time ever), which apparently over-pressurized the system and it dumped the refrigerant, which only days before had been checked at full. So I know that there are no leaks in the system as a possible problem and that I have refrigerant, and that it is not low. Just forgot to add that before anyone responds. Please help!

6 Replies

HARRY P

MECHANIC
2,292 POSTS

Hello. To be clear, this is not a dial zone climate control, right? Because I had one of those and became an expert at fixing/fighting it. Being a single zone control, it's a pretty simple system, really. Your issue could be a broken/stuck blend door or actuator or you're just low on refrigerant. I know you said that you had it checked and vacuumed and refilled a few months ago, but I'd start by having that checked again. A leak could have developed in the meantime or possibly it just ran low when it got over pressurized. Over pressurizing could've created a leak at one of the seals in the system or wherever the weakest point was.

So, in short, check the refrigerant level. If it's low, put some dyed refrigerant in so you can locate the leak. Report your findings here and we'll proceed as necessary.

Harry

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Thursday, May 7th, 2020 AT 11:02 AM

HARRY P

MECHANIC
2,292 POSTS

Sorry I've been meaning to get back to you. Unfortunately, Ken, I'm pretty sure dual zone only comes on the Limited trim, not the Laredo. I've had several of each over the years and never seen it on the Laredo. The Laredo has a simple single zone setup

Okay. The next thing to do is to check that the under hood stuff is actually doing its job. Start the engine, crank the A/C all the way up, and open the hood. Look for the canister. It's a cylindrical silver metal thing with a couple of pipes coming out of it. I believe it's on the passenger side but could be mistaken. It should get pretty cold. Cold enough that condensation will form. If it's not that cold, then we have an issue under the hood and more testing is needed.

If it is super cold, then the issue is inside, probably with the blend door actuator or the door itself. I'm attaching Alldata's information on changing the actuator. Take the actuator off and with the car on switch the temperature between hot and cold and in between and see if the actuator moves accordingly. Give it a little resistance and see what it does too. If it does as it's supposed to, then set it aside and check the operation of the door by manually turning the rod that connects the door to the actuator back and forth. You should get hot and cold temperatures as you go from one extreme to the other.

Let us know what you find.

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