WA 500 Komatsu A/c blower motor

[Lewis12]

:Banghead WA 500 Komatsu A/c blower motor not working. I have power at the 6 wire prong pigtail. I believe orange is hot when fan is to be on and when a/c button pushed on, the orange and red wire are both hot at the same time. But still the fan will not turn. Does anyone know if these units have a resistor somewhere. The fuses are good for the a/c blower motor and a/c compressor didnt check the rest but will check them all anyway. The pig tail for the blower motor only has two wires and they are for the orange and red hot wire when a/c on. ointheadSo does someone know how this blower motor gets any ground since it doesn't have a ground wire at 2 wire connector plug in coming from the harness. Has anyone had this problem yet.

 

[DK88]

What series ? Wa500-? Sounds like your describing a -6

 

[Lewis12]

It might be not really sure how to tell what series it is. Just know it is a WA 500 komatsu wheel loader.

 

[Lewis12]

I think it might be a WA500-3 series ill repost tomorrow if am wrong but am gunna go with 3 series will look at my manual tomorrow to be sure.

 

[willie59]

Is the ID tag missing on the machine? The dash # should be on that tag along with the machine serial number.

 

[kshansen]

Where I worked we had a WA600. Fun part is it had a non-Komatsu built cab even though it was bought new from the Komatsu dealer. Took a good parts guy at the dealer to find the correct information on the heater/AC unit. Parts book we got with the machine was wrong on many things as was the service manual.

I don't recall any heater motors on any equipment that were grounded through the case.

One question I would have is how did this problem present itself. In other words was it working one day then the next day it would not turn on or has it not worked for several moths and this was the first time someone decided it should be fixed?

I know it might be a little "caveman" but I would be tempted to run some temporary wires from say a 12 volt battery right to the motor. Positive to on wire and negative to the other to see if the motor will run. I know it's probably a 24 volt motor but 12 volts will make it run and not make as many sparks if it is wrong! If it does not run when hooked that way you could then try grounding the case with the negative wire and putting power to one lead at a time to see if that makes it run.

Another option would be if you have a known good motor of any kind, even a wiper motor would work, temporarily hook it to the connector leads and see if it runs when turned on. Or for that matter how about hooking a 24 volt headlamp to the leads to see if it lights up?

 

[Lewis12]

Yes it is a WA500-6 series.
I ohm the 2 spades coming out the blower motor were the harness pigtail inserts to and got 3.5 ohms. Another thing when i turn on the fan I hear the relay click. I also checked the resistor with 3 wires, black, blue with 1 red mark and blue with 2 red marks. The blue with 1 red mark is hot when you turn on the fan but the other blue with 2 red marks never is on. Also I believe that the black maybe ground.
So I went ahead and also ohm the resistor the black with blue and 1 red marks is showing 1.888ohms the black with the other blue and 2 red mark shows 0. And both the blue together show 0 ohms also. This blower motor is new because it was swapped out thinking that was the problem but still nothing, before I rule this a defective blower motor from the factory gunna go ahead and replace the resistor.
Also I got the old blower and connected it the the loader and put a ground wire on the blower and it still didnt do nothing. So I checked the voltage at both the 2 hot wires going to the blower spades and i got 25volts.

 

[kshansen]

Have you tried to put power to one of the leads on the old motor and ground the other lead?

If this is anything like a Cat heater setup with a three speed fan. Low speed is power in to on end of resistor from switch with power out the opposite end going to the motor, mid-speed is power in to center of resistor and power out the end, high speed is power straight to the motor not going through the resistor. High speed will have power showing at the output side of the resistor.

Hopefully someone will come forward with a wiring diagram for your machine. Have you tried to see if dealer will print one out for you?

Just replacing parts hoping to stumble on to something that makes it work takes way more time and money than just understanding how a system works.

Could be something as simple as the relay having burned contacts. It could still "click" but not send power to where it is needed. Even with a bad resistor I would expect the fan to run on high speed as in any system I have seen the resistor is only in the circuit for the lower speeds.

 

[Lewis12]

I will try hooking up a 24v light to each of the 2 leads going to the blower motor just to see if it will light. Also going to hookup a ground wire and a hot wire to the old blower motor. will report back with any updates.

 

[DK88]

theres 3 hidden fuses behing the left brake pedal. behind the tin cover. check those.
put a 24v light on the orange and red wire under the cab floor.
if u jump a-c on the 3 pin connector the fan should go to high speed.

 

[Lewis12]

:cool2Okay the 2 males spades coming out the blower motor have a orange and red with white stripes wire going into the blower motor male spades. The wires are both have power when you turn on the fan. The blower motor itself has a diagram showing a positive and negative at the 2 spades coming out the blower motor. Now I realized that the red and white wire that has power should be ground. So I cut the wire and attached it 2 ground at the frame. Now the motor turns when you start the fan. But I only have high speed but this is better than nothing.

 

[DK88]

Pm me you email address.

 

[Lewis12]

:notworthyA/c blower motor is now fixed.
Turns out that the red and white wire that had power going to the negative side of the blower motor was losing ground at the 3 wire resistor. Replaced the resistor and now the blower works have 1 side hot and other side grounded. Re spliced the wire that had a temporary ground to frame. and now everything is back like it was when it came from the factory. So if you ever have this problem and have to hot wires going to the blower start with the resistor behind brake pedal also behind the 2 relays.

 

[Daryn]

I have a WA470-6. The blower motor stopped working. It's an 8 wire plug. Checked under brake pedal. 3 fuses are good. Only power at two of them. One 5 amp fuse doesn't have power. Any ideas?

 

[Lewis12]

. The fuses you are talking about are for the blower speeds I beleive. My problem was the blower most the time and then one time I replaced the blower and it still didn’t work because the resistor that is behind the fuses you are seeing was bad. The resistor is mounted on the duct for the trap to open and close for the heater.

 

[Dirt Reynolds]

Wa450 5l the fan/motor was just replaced...hooked it up ran for about 5 seconds then quit and will not restart. Fuses are good, relay is clicking when I turn it (fan) on or change speeds...gonna test the motor off my truck battery and see if it works before taking it back. If it does work I'm stumped...

 

[Dirt Reynolds]

Wa450 5l the fan/motor was just replaced...hooked it up ran for about 5 seconds then quit and will not restart. Fuses are good, relay is clicking when I turn it (fan) on or change speeds...gonna test the motor off my truck battery and see if it works before taking it back. If it does work I'm stumped...

***update*** the fan works, but will not work once I mount it...it runs until it blows a fuse which is why it was running for a few seconds then stopping...now I'm convinced it's the resistor behind the brake pedal because it keeps changing speeds even though it's set on high. I'm curious if the squirrel cage is up against anything back in there once mounted because it runs in my hand but not once its mounted...also I'm running out of fuses