Blower Fan Speed Control. OFF and HI only.

[Seanz0rz]

so, another causality of this weekend was my blower fan speed controller. off works just fine, and so does high speed, but low and medium are the same as high.

i remember coming across several threads about this sorta thing over at TOF, but for the life of me, in the last 4 hours ive been able to find nothing.

from recollection, i remember it being a problem with a electrical element on the bottom of the fan housing, but i could be wrong.

so what am i looking at replacing/fixing? is it in the HVAC control unit in the dash (mine has been moved, so i will go and check wiring as time permits), or is it on the blower motor housing?

thanks for the help guys. really annoying either burning or freezing in the truck!

[DHC6twinotter]

Sean, mine did the exact same thing. Turns out I needed a new switch. Bought a switch from the parts store, and it worked great. IIRC, they didn't sell one for the 4Runner, so I had to get one from a Previa, which from looking at their catalog with pictures, was identical. Never had an issue with it since. :thumbup:

[paddlenbike]

Also, check the blower resistor under the glovebox. Unplug it and remove the two screws and check for fractured potting material and a separation in the coils. $33 at the dealer for a new one.

It's the black box that says "M1" in the upper part of this picture. (http://home.off-road.com/~kemanuel/4Runner/mods/footwell_lights_unit2.jpg)

[Seanz0rz]

thanks ken, thats what i remember hearing.

any chance on doing a DIY repair using a off the shelf resistor? 33 is kinda expensive.

[paddlenbike]

You'll probably find a break in one of the 3-4 coils. I tried soldering them one time but it failed miserably. I also tried twisting them together where they separated, but the coil wires were so old and weak they kept breaking off. That was on an '88 Supra, perhaps you'll have better luck with yours since it's ten years newer.

[Seanz0rz]

ok so i pulled it, there are some fractures in the ceramic material, and the metal looks a little worse for wear...

have a couple questions: is there any connection that should be going to the right of this picture, the terminal closest to R and not part of the wiring harness?
http://i103.photobucket.com/albums/m141/hamiltoncomputers/DSC02492.jpg

are these cracks big enough to cause failure?
http://i103.photobucket.com/albums/m141/hamiltoncomputers/DSC02487.jpg
http://i103.photobucket.com/albums/m141/hamiltoncomputers/DSC02490.jpg

im hoping this is it, i have a spare switch at home, so i will likely wait to order till next week

[Seanz0rz]

i was playing with it last night, and dropped it on my desk (about 6 inch drop) and the entire thing just came apart.

whether that was my problem or not, looks like im getting a new one. time to call northridge toyota today!

thanks for your help, i will update and let you know if this solved my problem or if it continues.

[corax]

you could also see what other models that part number crosses over to and take the list to Pick A Part (if your dealer is cool, ask them to run a "parts interchange"). Most of the time those resistors are a pretty standard part and will probably only cost a few bucks at a junkyard.

[Seanz0rz]

well the problem with junkyard parts, mine died after 10 years. junkyard parts are going to be about the same vintage. its been extremely reliable until the day it failed (over 10 years of use). if i buy a new one (which i JUST did, 27 at NTP (before discount)) then it should last me another 10 years. im happy with that.

that being said. the resistor is a RETARDED way to control fan speed... it should have had a 12V speed controller... so much wasted energy expelled as heat.

[corax]

that being said. the resistor is a RETARDED way to control fan speed... it should have had a 12V speed controller... so much wasted energy expelled as heat.


That's the way the OEMs have been doing it for decades, it's just the simple and inexpensive way of controlling the speed. It's just in the last few years that the OEMs have started to use a MOSFET for variable speed control and a relay for full speed.

[paddlenbike]

I realize it has been dropped, but did you find some breaks in the coil wires?

[Seanz0rz]

so far no, but only about 1/3 of the block came apart, and i found a small coil. no breaks, but there is a ton of corrosion on the terminals going into the block.

[DeathCougar]

The high speed only is a Toyota failsafe that allows you to still have a fan. If low and medium speeds stopped working at the same time, its the blower resistor.

$33 is not that expensive, considering all you have to do is plug and play and you're back in action. What is your time worth to tear it all apart, and run around tryng to home-wire some resistor contraption that may or may not work?

Also, you never want to go used on those parts for the very reason Sean described. Used parts are great, but its just one of those parts that needs to be new.

[Seanz0rz]

ok so update. solved the problem, was not the resistor after all.

this one is likely my fault. while the resistor was cracked and likely needed replacing anyway, it was not the cause of the problem. the problem stemmed from when i had to lengthen the wiring harness to the control unit. my wiring was fine, but with all the vibration i see, the stock wires coming out of the connectors rubbed and wore through, causing a short that burned the butt splices and caused them to expand, resulting in a loose connection.

all is fixed and properly shielded from any more problems. didnt get pictures of the problem, had to fix it quick last week before the heat hit.