Fan speed switch not working.

anyone have the opposite problem? today my ac started acting up. It works fine on the first 3 settings, then when it goes to the last setting (high) it blows like its on the lowest setting. First time it happened I turned the truck off and restarted and the ac worked fine. Second time it didn't work at all, even with restarting it. Drove to work, turned truck off, waited a few minutes and restarted it and the ac worked fine on high. 2008 model fwiw.

 

https://www.tacomaworld.com/threads...nt-work-on-high-setting.643036/#post-23460625

 

It’s been ~2 months after “repair” of old connector by cleaning and tighten the connector. Still working fine.
Guess the Amazon repair kit will remain in the glove box for a while longer....

 

Thank you for your time and information that you gathered. The wiring document is an added plus.

So far, the metal jacketed resistor is working really well with the new square connector. Thanks again. I am very glad everything is working perfectly again.

 

2/8/2021
Thank you for this. I love the new parts. This new design resistor 87138-04070 works great in my 2012 Tacoma. I love the new square connector too. Thanks.

 

I have the updated resistor pack. New hip will not let me install. Stop by willya?

 

Kansas might be a bit out of my way.

I would be glad to if you were closer...
How is the new hip BTW?

 

Just a bit lol. Hip not so good, by now it should be 100%.

 

Thanks to all that have spent hours documenting and figuring this stuff out. I put the blame on Toyota with a poor design to begin with and then a solution that is like painting a moving train.

My history: (you can skip down to my solution)
Mine is a 2010 OR purchased brand new off the showroom floor. No one else but myself and a few minor trips to the dealer have touched it. A year after I bought it the blower motor started to squeak. I took the whole thing apart and polished the armature, commutator, bearings, etc. I lubed it up good and it ran for a year or more quiet. Finally it squeaked again. Toyota had an upgraded blower (expensive) but I bought it and it's been fine ever since. About 7 years ago I had the dreaded fan only on high issue. It was a burnt connection to the resistor. A little electrical cleaner, bending the contact to make a stronger connection and some die-electric grease (let's not get into its not a conductive grease discussion, I know that and that's exactly what I wanted). It worked fine for a few more years but finally really burned up again. This time I bought the Dorman aftermarket kit with a new resistor and plug. It worked great until my trip to Las Vegas last week. Great time to go out. I tested the resister for ohmage like specified and it was open connections on all pins. I ordered another Dorman resistor and it came DOA with no ohms either. Pissed off I went to dealer and got the OEM with the new upgrade harness. The OEM resistor now has ohmage. I verified all voltages in all switch connections and they are good. On LO I get 12V between pins 3/4. On M1 its 3/1 and 3/4. On M2 its 3/2 and 3/4. My common pin on the old flat connector is 3.

My solution:
My current pin layout of the flat connector is from right to left
A - Green with yellow stripe
B - Blue with black stripe
C - White with blue stripe
D - White with black stripe



Now I see in previous post that Toyota must have changed the pin and wire color layouts on the square harness. Mine looks like this



Sorry for the blurry photo but the top is 2,1 and the bottom is 4,3. THIS IS DIFFERENT THAN OTHER SQUARE WIRE PINNING.

1 is Blue
2 is Green
3 is White
4 is White with black stripe

I used the one from the chart caribe_makaira provided (thanks)



Since there are so many variables with the harness wiring, 3rd to 3rd gen, 2nd gen to 2nd gen, I decided to give it a try but used wire nuts temporarily and plugged in the new resistor.



It worked like a champ. LO is the lowest, M1 is a little faster, M2 is even more airflow, and HI is full blast. I then undid the wire nuts and squeezed them into water resistant butt connectors.

The harness number I bought at the dealer 4/13/2021 is 82141-04Q80 ($19.19). The resistor is 87138-04070 ($39.59).

 

One thing I'm noticing while connecting my new wiring for the square plug is there's 2x12awg(approx) and 2x18awg(approx) wires on each side of the connector.

On the truck side wiring I have:
White/blue 12awg
White/black 12awg
Blue/black 18awg
Green/yellow 18awg

On the new square plug(Toyota):
1: Blue 12awg
2: Green 18awg
3: White 12awg
4: White/black 18awg

The diagram by @caribe makaira shows connecting the 12awg wires to the 18awg wires. I'm not comfortable with that without knowing better what amp draw there is. When your blower is running do you notice the 18awg wires getting hot particularly the white/black?

LO: White/black 12awg <> White/black 18awg
M1: Green/yellow 18awg <> Green 18awg
M2: Blue/black 18awg <> Blue 12awg
HI/Motor: White/blue 12awg <> White 12awg

 

I've been running it since April and even have reached under there to feel the wire. I don't detect any wire heating up. I wrapped the wire in electrical tape and it doesn't look melted. I feel that the 18 ga. is adequate for the amperage involved.

 

Having the same problem, fan only works on high, thanks for your help everyone.

 

Just to ease my mind, I don't like working off "feelings" with electricity... Granted I don't have exact inductance/resistance/emf specs of the blower motor I think have the amp draw reasonable enough to make a good call. If you're bored too have a go at it with the link below.

Hi: 20.8A
M2: 10.8A
M1: 4.5A
LO: 3.7A



http://www.falstad.com/circuit/circ...WTYq3X9KH2ZEYlnW5sGbjWnkRcY-hTIKQ+KtoDizNg2EA

 

Well it is tied to a 50 Ampere Fuse, so I'm pretty sure your worries are for nothing. 12 AWG at ~ 12 VDC should be good up to about 40 some odd amperes.

 

the problem is the 18awg wires not the 12awg. Pull that 50 amps down the 12awg no big deal and then bottleneck it into the 18awg

 

Yeah I did mess up the 12 / 18 AWG thing...

A conservative number for several feet of 18 AWG would be 16 amperes. Here we are talking about a few inches.

18 AWG can still handle that little fan motor...

Did you think about using an amp meter on the wires to see what it is actually drawing for current?

I highly doubt that that little DC Motor is drawing 20 amperes or even 16 amps.

Well I guess you can rewire the harness if it would make you feel better.

 

Couldn't find my amp clamp. Then why did the glorious toyota engineers use a 50amp fuse?

 

The 50 Ampere heater fuse also supplies power to the A/C Amplifier, Damper Servos and the A/C associated circuits sensors.

Why did they choose to use 18 AWG Wire?

How many Tacomas are on the road? How many fires have been caused by under sized wire?

 

Your circuit above is really meaningless if you don't have the motor specifications... Other than that, it is pretty.