Haven't a clue, but you could test fan by disconnecting it and hooking it up to a direct 12v source before buying anything.

 

Pretty sure when the resistor block fails, it's toast.

 

Remove the glove box and there it is ....



... your super lucky! I had the tear most of the engine bay circuit and box fuse box out just to get to the one on our Buick PA! It was one major PITA!!!

 

This is the one that was on the Buick PA. I found out that they fail because the fan is taking more and more amps to pull the same amount of air, so I replaced both. You might do some research and see if the same holds true for the Ram. I'd hate for you to drop $40-buck on the Blower Resistor only to find out you have to do it again plus the fan.

:imo

 

Dang, so does this sound like what's wrong?

 

The difference in-between your truck and the Buick PA the you can control the fan speed. On the PA, you set the temp and controller adjust the fan up and down. There's two buttons where you can over ride the controller but it easier just to set the temp and leave everything on 'auto'. So on your truck, you will also have a fan control relay. Most of the time, a relay works or it doesn't. If you can control the fan and it changes speed with the switch, I'd look at the resistor and fan as being the problem.

Let me dig into the system a-little and see what I can find.

 

The only thing I'm find for the 02-08 Rams has to do with fan speed failure. One, two, or three speeds fail but maybe one works; something like that. Or the fan doesn't work at all because the fan motor failed. I'm not finding anything where the fan comes on and then reduces speed.

Just to help you see how it's done, I found a YouTube clip where a guy pulls one to replace the resistor. You can see fan motor to the right and there are only three 8mm sheet metal screws that hold it in place.

2002 Dodge Ram blower motor resistor swap

I hope this helped ...

 

Cool! Thanks Dave.

Truck ran great though those HUGE mountains with the SuperChips and Shift Schedule adjusted. Man.. like I got 200 extra horsepower!

We left the A/C off all weekend as it was pretty cool in Greer Arizona. We left it off the entire way until we got to Globe, hit 94 and I turned it on. Worked like a champ the entire way home.. only 1.5 hours with no issues.

Still going to look into that resistor.

 

Does the the fan still work on the 1,2,3 setting.Normally when a resister goes, youll lose 1,2,3 and only have high. If it were me, I would look more into the motor, or something in the wiring, or control switch. Ive never heard of a resistor causing this.

 

Starting to sound like the heat exchanger was freezing up. That would account for the air slowly stopping. You'd turn off the fan or the whole system and the ice would start to melt. But before it was gone, you'd try turning it back on and it would freeze back up and choke off the air again. Does that sound right? If it is, I would do a thing. To fix it, the shop will have to bleed of just the right amount. They bleed too much and you've be screaming the your A/C isn't working. The shop will hook it up and it will more likely be within spec's.

:imo

 

^^^^ yup, I think you nailed it, sounds like evaporator icing. ... IIRC might try setting fan to high speed, and set temp a bit warmer to avoid icing when ambient temps are cooler, as it was on that weekend getaway. ... Originally sounded like fan motor was causing the fading

 

Ok..

We drove from Chandler to Show Low - maybe 240 miles?? Was about 90 or so when we left. It wasn't hot in Show low, maybe mid 80s.

The fan was on 3 most of the way. I noticed it was somewhat getting warmer in the truck and went to click it up one and saw it was on 3. Clicked it to 4 and nothing really changed. Turned if to 0 and then 4 and it blew hard for about 4 seconds and then went down to about 1 fan speed (with the setting on 4).

But yeah - the fan speed was slowly going slower and slower until you could barely feel any air coming out of the vents at the highest setting.

 

Tell us how it works for the next few days. Usually an evaporator freeze up condition happens on long drives of constant a/c. The only problem I see with this theory is that you said that you turned the fan speed to 0 then back to 4 and it blew hard for a few seconds. If the evaporator was a block of ice then air still wouldn't be able to move through it until it melted completely. You could have a blower motor going bad which will eventually take out your blower motor resistor due to the large amount of heat and resistance in the wiring created by the blower motor.

 

When there change in the air speed like this and you come to a stop, do you have a great deal of water draining off the heat exchanger. The drain is on the passenger side of the firewall.

 

DK 3Gs, but are AC controls "manual" type, or some sort of auto system that self adjusts blower speeds?

 

You know, come to think of it, there was a time that I turned it off and back on and the fan didn't blow harder.

Also, when I turned the fan off, the A/C light stayed illuminted. Which when I normally turn it to 0, the A/C light turns off..

 

The heat exchanger freezing make the most sense. But I believe you're to the point that until you check the Blower Resistor, we're just guessing.

 

How do I 'check it' ?

 

Check-out the video chip on post number eight ...

 

AH! OK. At work I can't see the link..

I'll have to try it on the phone and see!

Thanks