The 4th speed on my fan hasn't work since I bought the truck almost 4 years ago, but recently the other 3 speeds won't work at all for the first 5-20 minutes of a drive and then randomly start working again. I haven't done a lot of digging to see what I can find, but the plug to the switch is connected properly. What could be causing it to work intermittently? There are no other electrical problems, only the fan.

Any ideas? I obviously would like this fixed before the cold weather gets here, which in northern NY is right around the corner.

 

My Jeep had a problem with it's fan controller; only low would work; replaced; went out again a year later..

The switches burn up.. being they are cheaply made; replace the switch connector; the second time it burnt up; it melted the plastic because of short in the switch and i cut each wire and used connectors.

Switches are faily cheap at the dealer.. 20-40 bucks i think. So I would replace the switch; if the motor is working on one it does not sound like the motor as the switch is upping the amperage/volts or w/e to the fan. Suspect should be the switch it self.

 

I was thinking it may be the switch but wasn't really sure. Is there anyway to test the switch before replacing it? I mean $20-40 isn't a ton of money but I also don't want to spend $40 if that isn't the problem.

 

You could check power outputs with a volt meter; but I know in my Jeep when i researched it was a common problem with Chrysler Controllers. Starting in 2000.

But if you say one speed works and the other's don't I just about bet you anything it's the switch.. just because i had this issue in my Jeep.. Just that Low worked and non of the others worked.

 

Sounds like the fan switch on the control head is bad. Remove the dash bezel and unscrew the control head from the back of it. There should be a black wire on the back of the fan switch, this is ground going into the switch. The switch works by sending ground to each of the 4 fan motor wires thru the blower motor resistor and then out to the blower fan motor. In other words, the fan motor always has 12 volts positive going to it any time the ignition is on. The switch sends ground to each of the legs of the resistor independently. Each setting on the fan switch and thru the resistor will give the motor more of a ground input, so it changes its output speed and air velocity.

Use a volt/ohm meter and set it to continuity. Connect one lead of the meter to the black wire at the back of the switch. Move the fan switch through each speed selection one at a time. When testing the wires one at a time you should have continuity between that black ground wire and each of the wires that control fan speed:

Low is tan
2 is light green
3 is light blue
4 is black/tan

If you have no continuity to ground on these wires when tested independently of each other, or there is continuity between any of the 4 fan speed wires, replace the switch. I hope it is only a $20.00 or $40.00 part, but I don't think Dodge sells just the switch. You probably have to buy the entire control head as one assembly. If it costs too much maybe you can find a good one in a junk yard.

Good luck with it

Jimmy

 

Thanks as always Jimmy, I'll look at it this weekend, probably Sunday and let you know what I find.

 

Hey Brad-

I don't know if you have bought or tried another fan switch yet but I just had to replace the blower motor on my truck. It had been acting weird lately, the fan speed and velocity of the air coming out of the vents would vary in relation to the engine speed and RPM. It never did that before. My truck also developed a low end rumble in my sub whenever the AC or fan switch was on. The higher the fan speed, the louder the rumble was. It was only from the sub, not any of my other speakers. My RCA's do run under the dash and in front of the blower motor but they have been there for years and never had that rumble problem, and I have been using the same Kicker amp for nearly a year now with no rumble problems either, so I figured it had to be the blower motor. Plus last night the fan was on high speed, and not much air was moving at all. If I changed it to low or the next 2 speeds, there was almost no air movement from the vents.

I did some testing today, checked current draw on the blower motor and all of that, it was only drawing about 14 amps on high speed. I ran a new ground to the blower motor and there was no change in output but the new ground wire got hot. So I changed out the blower motor and resistor pack too. I know that when the fan draws too much current it ruins the resistor pack, I had no burnt wires or anything at the resistor but I wanted to be sure I did everything I could to fix the fan. Plus the resistor is only $17.00 at Advance anyway.

I ordered a new blower motor and resistor pack from the Advance web site and paid for it online with my PayPal account. The regular price on the fan was $99.00, I saved $40.00 on the deal by using their online promo discount code CCABIN and picked the parts up at the Advance store. It only took me about 10 minutes to install the new blower motor and resistor pack, and now my AC is blowing real strong on all 4 speeds, just like a new truck. On the 3rd and 4th speeds it will move my hair. I have no more rumbling noise in my sub any more, either.

I just thought maybe if your switch panel checks out OK you could try a new fan and resistor yourself. I hope yours is as easy to fix as mine was.

Jimmy

 

Wow, thanks for the post. My girl friend was just noticing today how the air blowing on her feet was increasing when I accelerated and decreasing as I decelerated. I never noticed really since I don't wear sandals or flip flops. I didn't get a chance to look at it yet but I haven't really worried about it a lot yet since I drive with the windows down all summer. I knew I had to get it fixed before winter so it's working properly. I would like to get heat when I need it and be able to shut it off once I'm hot...

My symptoms sound identical to yours. Where is the blower motor resistor pack located? Behind the dash somewhere I assume? Is it as simple as taking out the old and putting in the new one? Sounds like it since it took you 10 minutes. I've never replaced a blower motor before. I'm really glad it is an easy fix though. I didn't feel like spending a lot of time or money fixing it.

Thanks again Jimmy. Fixing my problems again! Haha

 

Well if your fan switch is bad, you might need to look at that too, but mine was still switching through all 4 speeds, blowing just a bit more air on each higher speed and on the highest speed it was moving air, just not as much as before all of this started. I first noticed the problem with the fan speed changing according to RPM's maybe about 6 weeks ago. It was intermittent, it did it one day a lot, then it would be OK for a while. Yesterday it was real bad, the blower fan would even slow down during a clutch cycle when I shifted gears and speed back up when I was in gear and on the gas again. My wife and I went to Disney yesterday and I noticed it was varying the fan speed the whole way there. On the way home the fan was pretty much non-existent, even on the highest speed there was not a lot of air moving from the vents. The new blower motor and resistor fixed it all right up, it works great now but the sound of the AC has changed a bit. It is louder because it is moving more air through the ducts, but that is fine with me. Down here you need good AC in the summer like the guys up north need good heat in winter. It is still pretty hot here now, and it won't cool off until probably some time in November. I cleaned my TB and IAC today too, I had been getting a shudder and drop in RPM's when I sat idling like at a red light with the A/C on. Cleaning the IAC fixed that problem.

The resistor pack is under the dash on the passenger's side, in the bottom of the HVAC housing. It is white-colored, rectangular-shaped, about 1 inch by 3 inches and has two 5/16" screws holding it in place. There is a wire harness plug connected to it with maybe ten wires on it. To the right of the resistor is the blower motor, it is round, has a pair of maybe 10 or 12 gauge wires coming out the right side of it, one is green, the other is black and it has three 5/16" screws holding it in place. It is super easy to R&R both parts. It is easier to get to the resistor if you first remove the little duct that comes over from the right side of the transmission hump, I guess that one is the heater duct for the footwell. It has two 5/16" screws holding it in place too. Then the parts just drop down, you unplug the old ones, plug in the new ones and bolt them back in place. The new resistor will have plastic tabs on each corner of it that you have to cut off or snap off with pliers before it will fit back where it mounts in the HVAC box.

We drove the truck tonight and the fan is doing much, much better. I guess if it gets to the point where you need a new blower motor resistor it is best to go ahead and replace the blower motor too. I did some research and it seems the blower motor becomes less efficient and maybe draws more current as it ages, so that may be what kills the resistor. I do know the resistor failure is a real common problem, you see lots of posts about it here and other sites too. In your truck it may be possible that your fan switch is still OK but your resistor is toasted. You might try just a new resistor in your truck first. If you get all four fan speeds back, then maybe you can change out the blower motor so the AC and heat will both be back to normal and you won't need a new fan switch.

Jimmy

 

Thanks again for the information. I'll look at it sometime this week. Now that I do not have a garage it will have to wait until it is no longer raining. It is supposed to rain all evening and tomorrow, so perhaps later in the week I'll get around to playing with it. Sounds like a pretty straight forward fix.

It's starting to cool off at nights around here. Had a couple nights drop into the 30's, so cold weather isn't far off. Winter in the Adirondacks comes early and leaves late. Good heat is a necessity when temps can drop to -35 or so.