[cwpastor]

I don't know how many people on here still own older Dakotas, but if you do, you're probably well aware of the problem with burned up blower resistors. I've put 3 resistors, 2 pigtails and 2 blower motors in my truck and as of last week, my blower completely stopped working. I read a lot about this, and I've found 3 possible causes: bad ground straps, bad ignition switch, and poor quality replacement blowers. I'm also wondering if a small heater core leak can cause it? My last resistor lasted about 6 months, and I only used it on high for short periods and never used the AC. The consensus is it's caused by high amp draw by the blower. Does anyone have a diagnosis/repair pathway to help me get to the bottom of this problem? It would be great to have a comprehensive answer that covers all 4 possible causes.

 

[radioactive]

Just keep in mind that on HIGH the resistor is bypassed so that setting is the easiest on the resistor. It's not dissipating any power at all. In the other settings, the fan current flows thru all or part of the resistor.

I haven't looked into this, but my guess would be that it's connections that go bad and generate extra heat destroying the resistors.

 

[cwpastor]

Thanks for the response. That is why I only ran it on high. I got the same failure when I replaced the pigtail and the resistor as when I replaced only the resistor. In fact, I got the same failure twice even though I replaced the blower, resistor and pigtail each time. That's why I suspect the cause is elsewhere. It's always the same pin in the plug that overheats - probably the line in/power pin.

 

[radioactive]

Certainly an over load won't be good for the resistor pack. Were you using OEM parts?

I don't think coolant is conductive but hey? Maybe it causes corrosion on the connections. You should have seen that.

I'd like to understand how a ground strap or ignition switch can cause the problem.

 

[cwpastor]

I used aftermarket parts. From what I've read, the dealer's parts are the same, at least in the case of these parts.

I didn't notice corrosion, only heat damage.

I can't answer the issue, other than bad grounds can cause a lot of problems. I haven't noticed any other strange electrical problems in my truck. All the current for the blower runs through the ignition switch, so if there's a problem there, it can effect the blower circuit; same with the blower switch, although it is in the circuit after the blower and resistor.

 

[cwpastor]

I am going to try deleting the resistor plug and hard wiring the pigtail to the resistor. One thread I read had a comment about putting a jumper between #1 pin and #2 pin in order to take the load off the small lugs in the plug. If the lugs are not up large enough to carry the current, then all of them need to be taken out of the circuit. The failure in my truck is always #2 pin, which is the line in pin, because it is always carrying full current. I'll get back with a result once it's done.

 

[akrider]

I don't know how many people on here still own older Dakotas, but if you do, you're probably well aware of the problem with burned up blower resistors. I've put 3 resistors, 2 pigtails and 2 blower motors in my truck and as of last week, my blower completely stopped working. I read a lot about this, and I've found 3 possible causes: bad ground straps, bad ignition switch, and poor quality replacement blowers. I'm also wondering if a small heater core leak can cause it? My last resistor lasted about 6 months, and I only used it on high for short periods and never used the AC. The consensus is it's caused by high amp draw by the blower. Does anyone have a diagnosis/repair pathway to help me get to the bottom of this problem? It would be great to have a comprehensive answer that covers all 4 possible causes.

trace wires and check all connections as state before must likely some type of short/ high resistance somewhere, troubleshoot splitting circuit from fuse/ components to isolate

 

[cwpastor]

I modified the resistor. The pins are steel, so I could not solder wires to them. I cut away the plastic that surrounded the pins, and bent each pin to form a 3 sided loop. I cut 5 - 6" lengths of wire from the plug pigtail. Each wire was twisted around its bent pin and soldered to itself to form a very tight fitting loop. I checked the soldered loops when cool and though there was no solder bond to the pins, they were solidly fixed to the pins. Then, I bought some plastic epoxy putty and completely encased the pins in epoxy. The hardened epoxy performs 2 functions: it insulates and protects the connections that hang down into the the foot well when the resistor is installed, and it prevents the connections from moving, preventing shorts. I also put a jumper between pin #1 and #2 to decrease the load on pin #2, which is the power in pin and is always under full load. (It's also the one that burns out). If you inspect the resistor design, you will see there is already a jumper between 1 and 2 on the resistor just below the green insulation wrap. I checked the resistance on all the pins and it seemed to be the same as the new resistor I have on hand. I soldered and shrink wrapped the other ends of the wires to their respective wires in the car wiring harness. This arrangement deletes the plug and its connectors, which I believe causes the overheating.

We'll see if this is a permanent solution. There is a 40A fuse on the circuit, so if there is a serious problem it should blow the fuse ( I hope). In the past, I always smelled burning when the plug was failing; hopefully, if it gets hot, I'll be able to smell it before it gets too hot.

Thanks to all of you for your responses!

BTW, I don't know if it's just optimism on my part, but it seems that the blower runs stronger than it did.

 

[donram360]

Is the resistor buried on a 01 like it was on my 99?
I never had trouble with that on that truck thank God as it's way high up in the dash where the dash has to come out to get at it. I discovered it when I did the heater core.
I also have an O1 Durango and like you I have had multiple blower resistor and pigtail failures on. I keep a couple of extras on hand for this vehicle as a result. Sometimes 2 a year, sometimes one every other year. We've had ours for 9 years and it was obvious that when it failed on me The 1st time it wasn't the 1st time it had failed on this vehicle in it's life.
I'm about to go over 300k miles, and this has been the one thorn in this vehicle's side. I did replace the original engine and rebuilt the transmission just shy of 260k because of a couple of stuck wide open injectors washed out 2 cylinders, mine has the 360 ("5.9") but the blower resistor issue is the one thing that continues to piss me off about it. This thing has otherwise been great to us.
About 3 resistors and 2 pigtails ago I did replace the blower motor because I thought maybe it was tired, drawing more juice than it was supposed to be. That didn't change the tendency for this issue one bit.
And I've heard others with these same vehicles that have the same issue.

 

[akrider]

resistor should be under glove box area think two or three screws on a plastic piece when looking up from carpet area bellow it. hard to reach small screws and plastic piece (heating duct for floor?) and the two screws on heating resistor. Only had to replace it once, 2001 purchased in 2003 still going strong

 

[Zarn]

Thanks for the response. That is why I only ran it on high. I got the same failure when I replaced the pigtail and the resistor as when I replaced only the resistor. In fact, I got the same failure twice even though I replaced the blower, resistor and pigtail each time. That's why I suspect the cause is elsewhere. It's always the same pin in the plug that overheats - probably the line in/power pin.

Many times heat is an indication of a bad ground in the line (pin). Or look toward the blower motor & mount... water leaks around there? No fuses blown...? G/L

 

[donram360]

Yes I know well where it is on my 01. I've changed it enough. I was surprised to see where it was on my 99. I was just asking the other guy where his was located because his is a Dakota, as was my 99. I didn't know if the difference in location on my 99 Dakota and my 01 Durango was a year thing, or a Dakota vs Durango thing.

 

[Burned]

Dodge HVAC Blower Resistor Wiring Melted

 

[alschott]

You may want to change the blower motor if you are going through resistor assemblies. If the blower motor bearings are worn out, they may be causing more friction that requires more amperage, and then the resistor pack overheats.

 

[donram360]

You may want to change the blower motor if you are going through resistor assemblies. If the blower motor bearings are worn out, they may be causing more friction that requires more amperage, and then the resistor pack overheats.

I HAVE!!! 2X even!!!!!

 

[olsarge]

I used to have that problem on my Dakota. I was told that the connector pins from the harness to the resistor are junk and loose causing the problem. I hard aired the connector and had no more problems. (at least until I retired the truck - don't know if eventually the problem would have come back).

 

[jpbarton]

I realize this is an old thread, but the way I finally repaired this problem on my 2004 Dakota was to connect the wires on leads 1 and 2 together outside of the connector. I think the age of the blower was causing high currents through the card which the connector is not designed to handle. The blower resistor card was getting so hot on pins 1 and 2 that it melted the connector to the card and I couldn't touch the wires when it was running.

Pins 1 and 2 are already connected directly on the card anyway so this fix gives a parallel path for the current when the blower is on high. Additionally, it gives a parallel path for the current normally going through pin 2 to the blower motor on the other blower settings. So, it effectively halves the current that each pin is handling. With this fix, I kept the old burnt connector in place and the card doesn't even get warm when the blower's running. The blower also started blowing harder as well as it cuts the resistance on the card.