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

I bought the new parts; updated resistor and new pigtail wiring for it. Installed those today and everything's working well. I updated the OP to reflect this change and updated the pictures some.

@Jimmyh I see in your post earlier that you also show some parts for replacing the connection at the blower motor itself. I didn't check this connection, so I don't know if mine's possibly effected or not. Is it your experience that this connection is commonly in need for repair along with the blower motor resistor wiring?

 

It is hit and miss... Very random. It only takes a couple of minutes to unplug it and check.

 

Gotcha, I'll make a point to check mine soon. Thanks

 

good write up. mine is messed up but i unplugged the connector and plugged it back in and it works fine so i guess i’ll keep an eye on things

 

May as well fix it if you have the time and money. It will only get worse with time.

 

yep i’m going to be ordering one of these mine is acting up again!

 

question. is buying the resistor needed or can i just get the wiring harness?

 

Yes, you need to replace the resistor and the connector at the same time.

 

ok perfect thank you!!

 

Just scored the resistor and the harness off ebay $32 shipped with free shipping brand new in package! good deal

 

Great Write Up!
Thank You Sir!

 

I just did this repair. The 5.5mm socket was non-existent in my tool box but i found an imperial socket that luckily worked.

I soldered in the new pig tail harness and shrink wrapped it, along with good electrical tape as backup protection. Awkward spot to work in didn't take more than an hour to do start to finish. i replaced the resistor as well and also a bulb that went out in the climate control unit.

 

I have the opposite problem, mine fan/heater will blow on all settings except high. I've checked my resistor and it's not burned or melted, and also checked the wiring harness and it has no burn or black marks on it either. I'm perplexed.

 

Here's the schematic. The relay supplies power to the motor. The ground circuit goes direct through the switch to ground when the switch is on high. Since the switch also supplies the ground for the relay, the ground wire on the switch must be good. I'm betting the switch is bad or cooked at the white/blue wire switch terminal.

https://www.customtacos.com/tech.ol...toyewd/06toypdf/ewd/2006/tacoma/h/em01d46.pdf

 

So you are stating that you think it's friend at 3a on that diagram, on the back of the switch itself at the terminal?

 

You mean fried? Yeah, that would be my guess.

 

Thanks for the suggestion, I'll take a look at it tomorrow when there's day light.

 

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.

 

I received the resistor and wiring harness as a Christmas gift.
The roommate got tired of me asking him to reach down and wiggle the wiring harness

 

Well, that was easy enough and WAY overdue!