A/C Heater Blower Motor not working. Can I test the resister? (1 Viewer)

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So my blower motor quit working. so far I have..
. Reset and the breaker is good.
.The switch does other things, the fan just will not come on.
. removed the fan motor, ran power and it works great.

I have found the plug next to the gas pedal and unplugged it, before I order one, is there a way to jump it to make sure that is where my problem is? Everything else seems to work.
 
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A better question might be, Can I skip the resister and make a jumper to validate that it is indeed the resister, I am having trouble getting the resister out of the A/C box right now but it appears the springs are broken.
 

ToyotaMatt

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A better question might be, Can I skip the resister and make a jumper to validate that it is indeed the resister, I am having trouble getting the resister out of the A/C box right now but it appears the springs are broken.


if any of the COIL springs are broken on the blower resister , then its time for a new OEM resister ..........

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I’m pretty sure I have the resistance and wattage values for the resistor coils in my notes somewhere, I’ll look them up shortly.
The problem is that the long beads of insulating ceramic eventually break and cause the coiled resistor wire to fail. I used ceramic block resistors (soldered on to the stock base plate) to replace mine years ago.
 

Godwin

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I had an issue with the fan cutting out. I would turn on the fan, it would run for a short period of time then quit. After several minutes it would resume running. I swapped out the aftermarket circuit breaker in the fuse panel for an OEM CB and that cured the problem, fan runs without interruption.
 
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Ok, found the info. (btw, the resistor (p/n 87138-22030) price from Toyota 87138-22030 at the time was $101.50).
At high fan speed, the resistor unit is bypassed entirely, and the fan runs at full line voltage (high speed) so this is your first trouble shooting step.
The resistor block has three coiled wire resistors, and four terminals ; H, M, L and EH.
The resistance between EH and H is .5 ohm
The resistance between H and M is 1 ohm.
The resistance between M and L is 2 ohm.
My resistor between EH and H was good so I left it in.
I replaced the resistor between H and M with a 1 ohm 15 watt ceramic resistor (7/16” square x 2” long)
I replaced the resistor between M and L with two 1 ohm 5 watt ceramic resistors in series. (I couldn‘t find a 2 ohm with 5 watt rating) ( each 1/4” square x 1” long)
It has worked as well as new for the last decade!
 

ToyotaMatt

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Ok, found the info. (btw, the resistor (p/n 87138-22030) price from Toyota 87138-22030 at the time was $101.50).
At high fan speed, the resistor unit is bypassed entirely, and the fan runs at full line voltage (high speed) so this is your first trouble shooting step.
The resistor block has three coiled wire resistors, and four terminals ; H, M, L and EH.
The resistance between EH and H is .5 ohm
The resistance between H and M is 1 ohm.
The resistance between M and L is 2 ohm.
My resistor between EH and H was good so I left it in.
I replaced the resistor between H and M with a 1 ohm 15 watt ceramic resistor (7/16” square x 2” long)
I replaced the resistor between M and L with two 1 ohm 5 watt ceramic resistors in series. (I couldn‘t find a 2 ohm with 5 watt rating) ( each 1/4” square x 1” long)
It has worked as well as new for the last decade!

My NoS OEM Blower resisters are 1/2 that old dealer TAX price ......

1st time MuD member clients get a free 10% off Coupon code too ...

fyi
 

OSS

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There's a reason why the resistor block is mounted inside the air duct - IT CAN GET REALLY HOT.
Those coiled wires in the resistor block look suspiciously like toaster oven wires — because that's exactly how they work.
 
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OSS is totally correct, they get HOT which is why they are dependant on good air flow from the heater blower. If the blower fails, or the inlet screens get plugged, they will burn out.
And yes, ToyotaMatt, you are much cheaper, that is why I mentioned original price!
 
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Thanks guys, for for the sake of it, If they are bypassed at full fan, that means that my fan should operate with them good or bad at full speed.

The lower speeds would suffer.

I have power to the dash panel, it lights up, the A/C button lights up when depressed and the motor tested good. So I will go ahead and grab a new resister and circuit breaker and try that. Any other places or things I should look at? Relays or such?
 

g-man

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Any other places or things I should look at? Relays or such?

The relay, and the wiring should be tested. Using a low voltage 12v light tester or multi tester probe ground (I like using the 10mm screws at the bottom of the metal dash on either end of the dash...the same ones that toyota uses) or you can go to the nader pin on the door. Then probe the hot wire coming into the fan at the plug. You can unplug it for this and just probe the plug on the harness side that has the largest wire. If you get voltage, try putting the ground side of your tester to the other wire at the plug and see if you still get voltage. Testing the ground side of the circuit. Sometimes wiggling the wires while you test...you can find a loose connection or semi broken wire.

you could test the hot wires between the relay and the switch, and the blower and the switch, and you could try to jump the w-b ground coming off of the heater blower s/w directly to another ground.
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Ground C is the at the bottom of the schematic is a junction above the relays under the driver's side dash. You have to drop the relay rail and cut into the wire loom that come in from the driver's side firewall and find where all the white/black (W-B) wires come together. ...then the largest w/b wire from this junction goes to the 10mm screw under the drivers side metal dash near the fuse box.

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I had an issue with the fan cutting out. I would turn on the fan, it would run for a short period of time then quit. After several minutes it would resume running. I swapped out the aftermarket circuit breaker in the fuse panel for an OEM CB and that cured the problem, fan runs without interruption.
Where did you buy the CB? I am having a problem with mine after I replaced the radiator. The blower motor just quit working. Figured it was the CB since it was working before I swapped the radiator out.
 

Godwin

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Where did you buy the CB? I am having a problem with mine after I replaced the radiator. The blower motor just quit working. Figured it was the CB since it was working before I swapped the radiator out.

I had a spare from a parts truck. I think this is the part number 8265020011 and should be available online or at a dealer.
 

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