Hi All, Great post and I wanted to contribute what I gained from this post.
I just bought a used 2002 Durango SLT+ last month and it had a few issues that needed to be fixed and one of these was I did not have the high speed setting on the front blower motor.
I went to the pull-your-self junk yard and got a a/c control head unit off a 2003 and it had a different part number than my 2002 had but they looked identical. Thinking that the switch was bad on the high setting I bought it for $50.00 came home and put it in and the a/c and rear defroster lights on the control panel would flash on and off for some reason due to wrong part number I assume. However I was able to check the fan speeds with it and it was infact the same problem. High speed did not work again with the new unit installed so I replaced the unit back to the original one and fixed the lights not flashing.
So I pulled the resistor out and could not seperate it from the wire harness without breaking the resistor to do so. As I found the last pin on the resistor was fried and then plug was melted also badly.
So I went to the dealership here in Barrie, Canada and bought the resistor wire harness kit $113 CAD and as mentioned here it came with about 20 wires in it. 5 heat shrink insulators and the black clip needed.
The original part number was 5017124AA which isn't the one I got as it has been replaced with 5017124AC. It is different from the original in that it has a locking clip on the end and also has an insulator rubber gasket to lock the wires in place. I could not find a guide to put it together so I took photos as I went along and will post them here for those who may need the help as I did.
I attached 3 photos and sorry for the quality but the phone didn't take the best pictures but they are good enough for what you will need.
The first photo is the plug still in the truck with the resistor removed and the black wire was the one that was burned badly where it entered the connector and there was no insulation left on the wire where it entered the clip. I cut off the clip about 1 inch from the connector so I could remember the wire gauges / colors for the reasembly.
So now you have a fried clip in your hand and 5 cut off wires in your truck doing nothing. On to the new clip harness.
In the 3rd photo you will see the new clip and it has a small black clip on the end where the wires go into it. You have to remove this clip but don't break it off. If you are looking at the photo you need a very small screw driver i.e. for small electronics and there are 4 clips holding it on. Looking at the photo put your screw driver on the opposite side of were the wires are and on the long flat part 2 per side un pry the clips by pushing the screw driver in on top of the peg holding the clip on and lift upwards gently and you will get one side of then do the same for the other. Once this is done you will see a white rubber gasket with 5 holes in it. Pry this out with your screw driver being careful not to tear it. Once the gasket is out you have 3 pieces of your soon to be assembled clip. As my fellow Canuk wrote here you need to push the 5 new wires into the connector. You need 2 green and 3 purple. THe new wires have silver locking connectors on them. From the (wire side) of the connector insert the metal end of the wire in to the connector and it will click in place and lock. You will notice on the new wires in the kit they have a little barb that sticks down (towards center) of the silver connector. I put these all to the middle of the plug if you know what I mean and not to the outside. If this matters or not I am not sure but it locked for me this way. If it does not lock then try to flip the wire upside down and see if it locks in place. So here is the order.
Pin 1 - Green wire
Pin 2 - Green wire
Pin 3 - Purple wire
Pin 4 - Purple wire
Pin 5 - Purple wire
You should now have a black clip with 5 wires locked in place hanging out of it with the wires in that order.
Now for the rubber gasket. Feed the 5 wires in order onto the spliced end of the new wires you just put in to the clip so that they are not crossed over or you will not be able to put the gasket back into the clip as in the 2nd picture. Once this is done slide the gasket back into the new clip and push it in place. If you can't get it to seat exactly right the black end clip will lock it in when you reinstall it. Now feed the wires through the locking black clip and lock it back onto the rest of the main clip part and you will see in picture 3 what it will look like when its finished.
So now you have an assembled resistor plug harness ready for the install.
Back to the truck now I spliced the 5 wires in the truck harness about 3/4 inch exposing the wires. I spliced the new wires on the new harness the same 3/4 inch. Place your heat shrink tube on the first wire and let it slide to down out of the way. I spread the wires a bit and twisted them together like so. Make sure they can't pull apart (gently pull on the new connection) before you shrink tube it.
=====---- ----=====
(use your imagination here as I didn't take a photo of it.)
Put the shrink tubing over the newly connected wires and heat shrink with heat gun or use a lighter which is what I used. Be carefull not to melt the wires when doing this. Hold the flame about 1 inch below the shrink tube will shrink it without burning the wires. Rotate the wires around to get an even seal. Now that wire is done. Repeat this step for the other 4 wires but don't forget the shrink tubing for each.
Once this is done you should re-install the new Resistor to the truck as shown in the previous posts to the truck. This is easier to do so there are not wire harness in your way trying to screw in those painful 2x 8mm screws back in place!

It was infact the hardest part of the whole process. Once the new resistor is in place clip your newly built wire harness on to it and then test your new fan speeds on the truck. They will all work 100% now.
Word of warning though. You must change your blower motor IMHO also which is 99% of the time what the problem is or you will blow the harness and resistor again shortly after if you do not. Then it would be another $140 for a new harness and resistor anyways so spend the $100 bucks and order a new blower motor on ebay which is what I did.
All in all.
Part# 506157AA - Resistor $15.26 CAD From the dealership
Part# 5017124AC - Resistor wire harness kit $116.39 CAD From the dealership
Blower motor which I got on ebay - $85.00 USD delivered to Canada.
http://cgi.ebay.ca/Dodge-Dakota-Pickup-01-02-03-AC-A-C-BLOWER-MOTOR-FAN-/130513552644?pt=Motors_Car_Truck_Parts_Accessories&fits=Year%3A2002%7CMake%3ADodge%7CModel%3ADurango&hash=item1e6336c504
Total repair was about $216.00 CAD.
With those 3 you now have the piece of mind of not having a fire in your truck with your family in it. Good insurance if you ask me. Will it happen again? Probably in about 100,000miles or 160,000kms but you will be a pro at repairing it and you won't have to do it in 3-6 months if you don't change the blower motor also.
Anyways I wanted to contribute my 2 cents and this is a great post hope it helped a little bit.
Tombs