07 Taco keeps burning through blower motor resistors

I've had my '07 Tacoma for almost 2 years. I replaced the original blower motor resistor within a month of purchase. Had to replace the connector to match the new resistor style. That worked fine for several months, then I had to replace the fuse. In the last year I've burned through 3 resistors. after the second I replaced the original delphi female connector in position C because it was charred and looked like the tongue was damaged and not making a good connection with the resistor pin. I put a brand new resistor in and tested it - worked fine, but within minutes it was fried again. The blower motor itself is about a month old. I replaced it because I thought the old one was drawing too much juice because I ruined the motor balance when I cleaned it last year.

long story short, I'm not an electrical expert and can't figure out why i keep frying resistors. Any ideas?

 

Sounds like a short in the system that the fuse is supposed to protect that circuit from. Are you certain you are using the correct sized fuse?

 

I also wondered if it might be fuse related. I think I'll double check all my fuses tomorrow when I do some other work on it.

 

When the connector got charred did you only replace the connector or did you also replace a portion of the wiring near the charred connector? If the wire is compromised, but did not open circuit, it will act like a resistor and heat up when current flows through it (when your blower motor is on). Heat transfer from the compromised wire could result in your resistor module heating up and failing prematurely.

 

OK so I double checked all the fuses and they're all intact and the correct size.

Road2cycle - when I relplaced the terminal I cut the wire right at the base of the terminal and then stripped about 1/4" of insulation to attach the new terminal. I didn't replace any more of the wire. If I do that, how much wire do you think I should replace? A few inches?

 

Is the blower motor and resistor OEM Toyota or a Dorman? If it's Dorman you found your problem

 

• I ran into the same issue so I purchased these oem toyota Pigtail wire 82141-04M40 with the oem resistor. I also replaced the blower motor fan. No issues since then. No affiliation to seller just part numbers you need. You may also want to check to see of the connections at the ac control arent burtn.
• Best of luck
• http://www.ebay.com/itm/2005-2015-Tacoma-Blower-Motor-Resistor-W-WIRE-Pigtail-Genuine-OEM-NEW/331281546698?_trksid=p2060778.c100290.m3507&_trkparms=aid=111001&algo=REC.SEED&ao=1&asc=40954&meid=e0d7ccbdc40a4aaa803c4b7e4c0e0a70&pid=100290&rk=1&rkt=4&mehot=pp&sd=161674614490
  
• http://www.ebay.com/itm/161674614490?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT

 

It seems the usual culprit is a faulty plug....Does your plug going into the resistor show some burn marks?

 

All components are OEM parts, including a brand new blower motor. The first time I replaced the resistor the new style part came with the pigtail, which I installed. I may try getting a pigtail again.
I pulled the delphi terminal out of the connector housing and it looked like the female terminal wasn't making good contact with the pin on the resistor, so I replaced the terminal. I don't see any visible evidence of the rest of that wire heating up - no discoloration like on the connector housing.

 

This link might be helpful. Take a look at the 4th and 5th step. http://www.tacomahq.com/1089/broken-fan-tacoma-heater-air-conditioner/

 

With all that corrosion on that plug it is a wonder the blower motor works at all.

The only blower motor resister failures I ever had were from old age where they just got to brittle and fell apart

 

If your connector looks like the photo a post or two above I would have replaced any wiring where the insulation showed signs of overheating plus a couple inches. I think at this point if you can find a new harness that's going to be easier than replacing wires and individual terminals. Plus you'll have better confidence the terminals were correctly crimped by the factory (unless you have the specific crimp tool required for those terminals).

Make sure you use the correct crimp tool on the harness butt splices and that no wiring (metal) is exposed at the butt splices. Let us know how it goes.

 

Check to see how many amps the blower pulls. You usually have a failure when the blower is pulling it's Max amperage. If it's a 30a fuse and your blower is pulling 30a then it's on the border of blowing a fuse but not quite there so heat builds up and melts things. Replace blower with resistor and fix your wiring. Should solve it

 

Great ideas. I do have the right crimp tools for both the delphi and butt connectors. At this point I think I will replace the whole pigtail with all 4 wires. By the way, the stuff in the photo that looks like corrosion is actually terminal grease, although I don't know why it appears blue since its actually clear. I use it on most connections - if anyone has a strong opinion as to why it might not be a good idea here I'd love to hear it.
I'm also going to take another look at the wiring behind the control dials to check for any signs of heat there.
Finally, I'll try to check the current draw of the motor itself.

 

Sorry I could only go from what I saw sure looks like corrosion in the pictures

 

It seems like the wires are going to ground somewhere down the line.

While the focus is at the motor, it's most likely further down, out of sight, where your problem exists.

A ground fault could be introduced at any point along the run of wires that exists around your pigtail lines.

When the wiring harnesses are installed they are grouped together and dash components are installed around them. There is a possibility during this process a connected or screw had caused the system to go to ground.

Also, while initially you had no problems, wear and time has caused the wires to become exposed and thus, gone to ground.

That's my opinion, and my experience with electrical components, especially in vehicles, this is what it sounds like.

 

Keep in mind that the circuit your resistor pack is in is ground based so if you have a bad ground, your resistance goes up for that part of the circuit. You can clean up your blower ground point really well and see if it makes a difference or not...or you could run a direct ground from the battery ground to that ground point and that might be the best way to keep your resistor pack from dying early.

 

So I took a bit of a break from this issue to deal with others. When I had it in the shop for another thing they said they think it may be bad butt splice connections, and that they would redo the splices by fully soldering them. Any thoughts on that solution? I'll be honest, I hate soldering because I plain suck at it, but IF that could be a solution I'll try it.

Also, Hondah and BamZipPow suggested tracking down a ground fault, or cleaning the blower ground point. How do I do that?

 

If you had a poor butt splice things would be melted around that connection.

loose connections cause heat

Maybe your not using the correct tools to solder maybe even the wrong type of solder

 

It is possible that poor butt splices are the cause of the problem. As mentioned above look for signs of melted/browned/charred wiring and connections. If you end up soldering the connections make sure that you get proper solder flow (i.e. no cold solder joints) and put sufficient heat shrink tubing over the soldered wires to prevent shorting.