I have now isolated the problem to the blower resistor. This resistor is different and more expensive for the ATC version. ~$48 at Rockauto.com.

 

I ordered the "resistor" at Rockauto.com, for $48 including shipping, plugged it in and the blower is fixed (Dorman part# 973027). By the way, the "resistor" is not a resistor, it is a power transistor, and that big aluminum thingie sticking into the plenum air flow is just a huge heat sink for the transistor. The transistor is much more efficient than the old resistor designs, since it is modulating the 12 volts with high frequency pulses, instead of just throwing away wattage with a hot resistor lowering the voltage below 12 volts for the lower speeds.

It is probably a MOSFET transistor, just guessing. And there is a lot of support electronics on a small circuit board inside the assembly. Easily $48 of content, which is why it costs more everywhere else including Advanced Auto ~$71, or $128 elsewhere on line.

 

Yup, correct but has it worked out any better than the resistor? I've read many posts concerning bad blower controllers on several forums and elsewhere. I'd bet if the two were compared the reliability would be the same dismal result. New isn't always better as anyone who has dealt with electrical systems on these vans can attest to. Lot to be said for the days of electro-mechanical relays.

 

You are exactly right, I was just defending the cost based on the technology they threw at it. In my opinion, the power transistor is too small to handle the blower amps, (greater than 10 amps) based on power transistors I see on other devices with even less power handling. It looks to me like they used one size transistor too small and put that huge heat sink on it, hoping it would handle all the heat that undersized transistor would see. From a consumer cost, not an energy efficiency perspective, the old resistor blocks made more sense and were probably more durable, even though they wasted more energy.

 

Similar situation with the radiator cooling fan "relay". They can't handle the heat. Both of these components are money makers for Chrysler Corp.

 

Chrysler does not make parts they send out schematics to people that make them .

 

Regardless. If it says MOPAR I would think Chrysler is making money not only on the part but on a chunk of the labor fees involved to troubleshoot and R2 the part.

 

Having worked at as a production design engineer as a career, I would guess that it wasn't the engineer who underdesigned it, it was purchasing who told the engineer that you aren't building a tank, you don't need military heat standards for that part, save a dollar. They overviewed all of our decisions, searching for thrifting actions, that was their job. We spent a significant part of our time justifying design decisions based on testing data and projected lifespans based on similar part history.

In defense of purchasing, if you let system engineers have everything they want, you would have a more expensive car, that might motivate a prospective customer to buy a Japanese or Korean car instead. Note that neither the Japanese or Koreans have a national defense budget to pay out of their corporate and individual taxes, so they can make things cheaper. Note that we have decided to be their national defense and we pay for it out of our taxes, and we will not allow them to go nuclear. How long has WWII and the Korean wars been over, and how well does this policy serve American manufacturing? Huh oh, now I have gone political.

When the old resistors failed, usually the failure mode was to lose one blower speed at a time, as the individual resistors failed, not all blower speeds as occurs with the power transistor design. From a customers perspective, the resistor design was a better failure mode. But that evokes a similar long conversation on how important saving 2 amps on medium blower speed is because it allows a smaller, less expensive alternator. You can also use a low current switch to control the blower with the transistor, an second cost savings.

The transistor "resistor" that I just replaced had gone 110,000 miles, probably that was within the design target of the part, at the time. That mileage target constantly moves up. You should note that Japanese, European and Korean cars have similar issues, as discussed on similar forums.

 

Correct part failures are built into the cost of the product any way there is a thresh hold that if a failure rate is under this amount they are ok with it. If it goes over then they change things around because well hate to tell a bunch of people this but that is capitalism and how it works. They are out to sale a product and make the most out of it with also being competitive in the marketplace. GO start up a business and see for yourself how basic economics play out.

 

I have the same problem, even after running for a hour my auto climate control says delay with the count down and keeps reoccuring and if I change the locating for the fan to blow the speed also changes on the dial. I think the old owner did something behind the glove box because I see tape in there and last time the fan didn't work it started when I closed the glove box door, any ideas?