Replacement of HVAC Blower Motor Resistor

This is how I replaced the HVAC blower motor resistor in a 2005 Tacoma.

Symptom of a bad resistor for me has been that the AC/heater blower will only work on high. At first this is intermittent, then later pretty much constant.

First let me say that this is the 3rd resistor for this truck. They seem to last me about 18 moths. The first replacement was under warranty, and after they checked everything else out they decided to replace the resistor. Once they decided it took the guy 15 minutes or so to replace it. A few days ago I called the local stealership, the service estimate was 1 to 2.5 hours labor and $38.17 for the resistor (MSRP $28.89). That's why I decided to do it myself.

The first problem is finding where the darn thing is. By looking at the service manual it appears to be next to the blower motor, actually it sits right next to the firewall a little to the left (drivers side) of the blower motor. Now a skinny little guy could get to it rather easily, but for a big old fat guy like me (59, 6’6”, 325lbs) that isn’t at all limber - not so easy. I tried to get up under there but just couldn’t my head and shoulder jammed in enough get a good view.

I ended up pulling the front passenger seat for access. It still isn’t easy - but at least do-able.



Now that I know where it is I believe that I could change it without removing the seat.

First step after you find it is to disconnect the wiring harness, it comes off pretty easily, next there are 2 screws holding the resistor in. There is one on the left as you look at it, there is a second one on the right in about the same position - but on the back of the unit and pretty much not visible. I couldn’t see it no matter how far I got under the dashboard.



You can feel it though. You will need a 5.5mm socket on a ¼” drive ratchet. It needs to be a ¼” drive because anything bigger won’t fit on the back screw and in the space available. As it is I had to pull the carpet out of the way to get on the hidden screw.



Remove both screws and the resistor falls out in your hand, put the new one in, making sure that the little catch on the resistor for the plug is facing you.



Start both screws, and lightly tighten, connect the wiring harness AND . . .

Congratulations!

That’s it you are done.

 

Thanks so much for posting these instructions! Had no idea replacing the resistor would be so easy.

 

whats the resister look like, and the clip thing you were talking about?

 

Sorry,

You can see the bottom of the resistor from the pictures included in the first post, once you have removed the electrical connector, and removed the 2 screws holding the resistor up the resistor, it will drop down into your hand. The top of the resistor is a flat probably, 1.5 inch wide and 2 inch tall by an 1/8 of an inch thick (from memory) and it has a ceramic covering (like it was dipped in a very hard paint). If I remember correctly it was white (ish) to light grey.

The clip thing that I was talking about is a latch that the electrical connector snaps over. I don't think that it really matters if it's facing front seat or the firewall for installation, but it will sure make it easier to remove the electrical connector if/when the resistor fails again.

Before you replace the resistor try tightening the electrical connector first. Push it up and wiggle it a little. This has been keeping my current resistor working for the last month or so. I’m thinking tomorrow I’m going to try to make an additional clip to hold the connector on tighter, try to tape it up using electrical tape. I’m not sure that the resistors are going bad or just not making good contact.

 

The pics where outstanding, was just wondering what it looked like.
great write up!

 

Thanks for this.

My Dads Tacoma has this problem (fan only working on high) and I am trying to help him diagnose the problem.


Edit: I sounds like the problem is the connector, not the resistor. I tested the resistor with a multi-meter and its working good. The connector is loose.

 

I replaced the resistor a few weeks ago following these instructions to the T and everything has worked perfectly since. Just in time for the crazy Arizona summer heat too!

 

I have this problem as well. I found out through the dealer that there is a loose connector on the fan resistor plug. Sure enough there is a discolored pin in the plug which the dealer recommends removing and tightening. I just need to figure out how to remove the pin from the plug. Has anyone done this? I'm not sure how to get the pin out and Aoto zone has never heard of this magic tool which is supposed to do the job.

 

I have this problem as well. I found out through the dealer that there is a loose connector on the fan resistor plug. Sure enough there is a discolored pin in the plug which the dealer recommends removing and tightening. I just need to figure out how to remove the pin from the plug. Has anyone done this? I'm not sure how to get the pin out and Aoto zone has never heard of this magic tool which is supposed to do the job.[/QUOTE]

 

Oh its good to find some info on this. I ordered a resistor that will be in tomorrow and then will tackle this job I will be sure to Check the wiring harness.

*************UPDATE:**************
Something told me to check the wiring harness first thanks TW. So I went out and gave the connector a little push up and what do you know the blower motor starts up!!!!!!!! Then I removed the connector and took a look. What I found is that one of the pins on the connector looked like it had been running hot and was a little discolored brownish. I cleaned and recrimped the connection to try and secure a "tighter fit". Put on some dielectric grease and snaped the connector back in every thing is still going good. Well at least I saved my self $30 for now. I hope that the wiring harness dos not end up becoming a problem. Anyone else have problem?

 

I was able to tighten the fit of the terminal with a small jeweler's screwdriver while it was still in the plastic plug. I then tested the old resistor by plugging it in uninstalled, and it works just fine. Be careful though, these things get very hot! I suspect that the first resistor is still good also,so be sure and check that wiring as it appears to be the real problem, and you can possibly save that forty bucks!

 

I replaced the resistor on my 05 Tacoma and it lasted only 1 month. I was told now that it is the wiring pigtail harness. The dealership sells this for the rip off price of $1,200. Does anyone know where i can find a replacement pig tail either aftermarket or junk yard? I found that the Chevy Coloroda has this same problem and you can buy the pig tail replacement for the colorado at almost any auto parts strore for $38.00 ..but cant find the part for Toyota except at the stealership..what a scam. Any help would be great .

 

How does the OP not have more rep for this?? Thank you!! This is such an annoying fault and I will be replacing mine today. Had it not been for this thread I might've paid the dealership unnecessary $$$ to get it done.

 

Sub'd for later use, thanks so much!

 

Awesome post. Used this to change out my resistor. The pictures with the location were super helpful.

also, wanted to note that the replacement resistor i got was different from the one I took out of my 2006. I guess Toyota updated the design or something...

 

Awesome! Thank you!

 

Had this same problem and found this post super helpful! However I was about to order the resistor and decided to do a physical inspection first. Being that I am an AT in the Navy (Aviation Electronics Tec.) I very familiar with the look of a blown resistor they will typically look cracked like a clay pot that was baked too long in the oven ( as many resistors are made from ceramic) and in fact the resistor in this case is ceramic as well! well I took a look and it looks fine, I also gave it a sniff as they will often have a burt foul smell...still nothing. Having said all of this there are cases where nothing appears to be wrong and the resistor is in fact beat, this of course can all be solved with a simple multi-meter test. simply remove the resistor from the housing and set your multi-meter to the Ω (ohm) setting and see what it measures (the resistor itself will have the amount you should read on it, mine said 600K) if you don't get the exact reading its not necessarily bad however a reading of OL or 1, 2, or 3 MΩ would indicate that this resistor is "open" or resisting far too much. OK enough resistor ranting...so the harness connector where the resistor plugs in can be your culprit for this intermittent or "high" only blower issue. Upon inspecting my harness connector it was obviously burnt ( this does not necessarily mean its bad but its certainly on its way) this connector has ports which make connection via spring pressure. now if yours looks like mine and you can very easily see which line is burnt, chances are the connection in there is not tight enough making for a loose or bad connection hence where the heat comes from. Solution? get something very small and gently lift the the connector to create a tighter connection. Re-install the resistor and BAM no more intermittence. This may not be the case for all but certainly worth attempting before ordering a new resistor!

 

Anyone know what gauge the wires are?

 

Haven't posted here in awhile. That's Because the fix has worked flawlessly since. Hey I think the wire gauge is somewhere around 20 or 18 IIRC

 

Good to know, 20 or 18 seems small. I loosely put my wire strippers on the wire and my guess is about 12 or 14.

I already bought the chevy plug vv. I'm looking at using trailer harness wire for the extension. Don't feel like paying Toyota for their wire and plug.

TSB PDF for reference