2003 Dodge Ram air conditioner help

**Stuart** · #1 07-27-2009, 11:33 AM

So the problem is that you get out on the highway and she'll cool good at first and then slowly start to lose it, even the blower doesn't blow as hard. Also I notice kind of a stale odor (not anti-freeze). Most of the time you can turn it off, wait a few minutes, flick it back on and it will cool again. In fact, the other day when driving home from Houston, it got so cold we had to turn the fan down a notch. I don't think it would do that if it was low on refridgerant. Any ideas? Maybe some kind of vacuum problem somewhere?

**rockyraider** · #2 07-27-2009, 11:38 AM

Stuart, my '02 Ram developed a condition that may be similar to yours. My a/c would blow cold when driving down the road but as soon as I would slow to an idle (like at stop lights, etc.) it would begin blowing warm. I did a quick internet search and found that a blown a/c fuse is a common cause of this as your compressor won't act correctly with the fuse blown. Sure enough, I began pulling the 5 amp fuses that are located in the fuse box just to the right of the engine and low and behold about the third one I pulled was burnt. Replaced it with a $.50 5 amp fuse from Autozone and it was fixed. Pull you fuses and make sure one didn't blow. Good luck. Let us know what you find.

**speckle-catcher** · #3 07-27-2009, 11:39 AM

there are 3 screws that hold a fan motor in place under the glove box - pull those and check for obstructions. Also check the glove box to make sure nothing in it is getting sucked in towards the vent.

or - your fan motor in the engine compartment (drivers side I believe) could have gone out. Which might explain the AC seeming to work properly at highway speed.

**wish2fish** · #4 07-27-2009, 08:33 PM

Quote:

Originally Posted by speckle-catcher

there are 3 screws that hold a fan motor in place under the glove box - pull those and check for obstructions. Also check the glove box to make sure nothing in it is getting sucked in towards the vent.

or - your fan motor in the engine compartment (drivers side I believe) could have gone out. Which might explain the AC seeming to work properly at highway speed.

That is what mine was Fan Motor 02 Dodge Ram. It would be cold while driving because air is pushed onto the fan which turns it and pushes cold air through the truck. When you slowed down fan would stop spinning = no cold air.

**Stuart** · #5 07-27-2009, 11:46 AM

I'll check the fuses. Last summer we had the opposite problem where it wouldn't cool while in stop and go situations. The condensor fan had gone out so that was an easy one to figure out.

**bowed up** · #6 07-27-2009, 11:55 AM

My '06 ram since the beginning will cool great while at speed, but when you slow down to come into town off the highway it is like the compressor cuts off, dealership says there is nothing wrong, but what do they know.

**nightgigger** · #7 07-27-2009, 12:10 PM

Something that might be worth checking, is if the heater core is getting hot water.
It sound like your AC is fighting with your heater, as the engine warmes up the AC cannot keep up with the heater. My son's truck had this issue, the cable that let water in to the heater core was stuck in the open position.

**Hop** · #8 07-27-2009, 12:34 PM

I think that year model had problems with the blend door breaking (try a google search).

If not.. It could be freezing up. If your evaporator has sucked in some stuff it could cause it to freeze. Do you have an in cabin air filter? I'm not sure if dodge installed those. Also check to make sure that there is condensate dripping under the truck.
A quick check without gages can tell you if it's low on refrigerant. Pop the hood and have someone rev the motor to 2k to simulate hiway RPM's. Watch the A/C compressor to see if it's staying engaged via the clutch. If the pressure's drop too low or get to high the clutch will disengage the compressor untill it reads lower or higher pressures. The compressor should not cycle on and off if the A/C is working right.
--Hop

**Stuart** · #9 07-27-2009, 12:48 PM

Hop, that blend door sounds like something to look at. That would also explain why it seems like the air at times is very moist. I bet hot air is getting mixed in with the cold air.

**CatchinZ's** · #10 07-27-2009, 05:55 PM

I have the same year Dodge and mine did the same thing. It turned out to be low on Freon. Blows colder than ever now and no more drop in air volume.

Tim