(DIY) AC or Heater Only Blowing on HIGH? Here's a fix

dutd33 · Nov 12, 2023

2017_TACOMA_LIMITED said: ↑

Thanks everyone for saving me money! My wife's a/c in her 2014 would only blow on high and I found this issue and the fix here in the forum. I located the wiring harness under the dash and unplugged it. I noticed the plug had a black mark on the connector and off to Toyota I went. I ordered a new harness ($21 and change) and tried to order a new resistor. The parts guy said the computer shows 1,300 resistors on backorder across the nation. The next day I was at Toyota with my wife for scheduled oil changes on my 2017 and her 2014 Tacoma. The wiring harness was in (no telling about the resistor), so I paid for it and then took it out to the service bay to inquire about how much it would cost to install. It was going to be over $200! Incredible. I made a trip to Lowe's for some butt connectors and about 30 minutes of labor and the harness was connected and plugged in. The a/c works fine now. I love this forum.
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Sorry to bring back an old thread, so in your situation it was just the harness/connector that was the issue and not the Blower Motor Resistor itself, is that right?

I think I'll do a visual inspection of the connect first to see if there are any burn marks.

Thank you everyone!

CaptQuinn · Nov 17, 2023

dutd33 said: ↑

Sorry to bring back an old thread, so in your situation it was just the harness/connector that was the issue and not the Blower Motor Resistor itself, is that right?

I think I'll do a visual inspection of the connect first to see if there are any burn marks.

Thank you everyone!
Click to expand...

I had the same issue. Burn marks very evident and replacing the connection (after Stealership replaced the blower motor $350, which helped for 2 days...) completely remedied the situation. Fast fwd many years (my truck is a 2013) and I've had to replace the blower again but that connector/harness still working guud!

dutd33 · Nov 18, 2023

So I gave the blower a few taps and it's working again. For how long I don't know but I've ordered the Blower Resistor Kit.,

Thank you everyone for their help!

mark_tga · Dec 25, 2023

Thanks OP for the write up. Solved my issue. Had it fixed within half an hour.

Comataco · Jun 9, 2024

My 2013 is running but not real cold & fan doesn't seem to blow hard enough . I'm concerned it won't cut the mustard on long 100 degree trips this Summer ? I'm running the fan on high almost full time in 75-80 degree weather now & recycle on. I live in liberal Washington state that made R134 A illegal to sell (fortunately I'm close to Idaho who does sell it & less strict firearm laws) ha ha Anyway THANKS for all these hints ,I keep them on my favorites. PS: My 2002 Tundra blew strong cold air like crazy (should have kept it , I had a weak moment) ! Always grateful for help !

Chappie · Jul 29, 2024

This was exactly my problem in my 2012. Thanks for the easy, cheap fix.

FarloN0607 · Sep 28, 2024

I think this literally just happened on my 2013 Tacoma at 222k. Parked my truck for 10 minutes, AC has worked flawlessly for the entirety of owning it since 2017, cranked it back up and no AC… until I cranked it to high. Same with heat. Guess I need to start here.

jb2112 · Apr 6, 2025

Hey when u got your ac replacement wires, were the wires different colors than what’s attached to the truck? My truck has blue green, blue, pink, black white and wires that came in are white, white black, black, green white.

bbinSF · May 9, 2025

Hey guys,
I had an alternative idea based on the blower motor resistor test diagram.

Why not replace the resistor plug with soldered in, high-wattage resistors?

bbinSF · May 12, 2025

another alternative is to remove the #3 wire and terminal from the plug enlargen the hole, solder a wire directly to the terminal on the resistor, weave that wire through the new hole in the plug and use a wire nut to make that connection. Seems like the current coming through the terminal is causing sparking or overheating and then resistance grows and it stops working.

Williston · May 12, 2025

jmanscotch[OP] initial post: ↑

A seemingly common problem with our 2nd Gen Tacoma's is the HVAC system will stop blowing on any fan setting lower than high.

Any one familiar with this symptom from a different vehicle (cough cough Jeep) will know it's a good sign of a failed Blower Motor Resistor. While it *might* be a bad blower motor resistor in your Tacoma, it might also be due to a bad connection in the plug that connects to the blower motor resistor.

Toyota has since issued a TSB for an updated Blower Motor Resistor design and calls to replace the connector for it as well.

If you find this scenario in your truck, you'll need to purchase two pieces for the repair:

- New updated Blower Motor Resistor - Toyota PN 87138-04052 $30 here on Amazon

Genuine Toyota 87138-04052 Blower Motor Resistor

https://www.amazon.com/dp/B00G6FDT7E
- New Connector for BMR - Toyota PN

$31 82141-04M40

82141-04M40 $20 here on Amazon

$31 82141-04M40

https://www.amazon.com/dp/B00TNNSWNC

You'll also need the following tools:

- 5.5 MM shallow socket (to remove the BMR)
- Wire cutters/strippers (to replace the connector)
- Solder, heat gun and shrink wrap -or- crimp connectors (to wire in new connector)

Let's start by locating the Blower Motor Resistor and its connection.

Sit in the passenger seat of your truck and look down at your feet, note where the middle of your left foot is. Then, get out and poke your head under the dash in that spot and look for this:

Unclip the connection and take a look, noting any signs of high heat, melting, burning, or broken wires. On my connector, it wasn't so bad that anything and melted to the extent of deforming, but I was still experiencing intermediate fan speed issues.

Note the 3rd pin from the left and the discolored connector and pin. This is from a high heat situation and is causing a high resistance connection that sometimes prevents the blower motor resistor from operating properly.

Since the repair replaces both the resistor and the connection, it doesn't matter if your issue is solely one or the other, it's smart to replace both as it's the long term, reliable repair.

On to the repairs.

Start by removing the blower motor resistor and replacing it with the new updated designed unit.

Use the 5.5 mm socket to remove two (2) screws on the BMR

Once the BMR is out, you'll see the difference between old (left) and new (right).

Reinstall the new blower motor resistor and screw it back into place.

Next is to replace the connector. You'll need to cut the old connector off and either solder the new connection or use wiring crimps to connect it. I prefer soldering, but I realize some folks will need/prefer to use crimps. Toyota's TSB on this repair calls for crimp connectors.

I cut all four (4) wires pretty close to the base of the connection. I stripped back the insulation on both sets of wires. Here's of picture of that happening.

The wires are color coded, so match the new connector up to the existing truck wiring and solder/crimp them back together. I've already soldered them and have the shrink wrap in place here:

I wrapped the wires up in a little electrical tape for neatness and plugged the connector back into the resistor, ensuring it seats properly and fully.

Would you look at that...I can now adjust my climate control to an acceptable mid range fan speed!

Cheers.
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Can anyone confirm when Toyota changed over and started installing the new revised resistor and connector in production?

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(DIY) AC or Heater Only Blowing on HIGH? Here's a fix

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