RichBinAZ

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Thought we had our first genuine problem with the xB MK1, which has been super reliable over the prior 60K miles.

The fan didn't seem to want to come on, according to my son, who had to resort to driving it around with the windows open. Not a problem now, but in a Phoenix summer - that is going to be an issue.

We took photos and documented what we did here just click on the first picture to start. The on-line manual is not that helpfull if you are diving under the dash in this area, so hopefully if you have to dive in there for one reason or another, this guide will help.

Could not find the issue in the end, as like all electrical problems, it went away as soon as it came up. Of all the components we looked at, the resistor looked the most likely, so if it happens again - we'll just change that out.

Rich

SentraSE-R

Props for the excellent DIY write-up. Thanks!

05sciko

this is the kind of stuff we need here!!! tank you for taking the time to document your work and help everyone else out in the future!!!

MrSwetz

This is great -- do you think this guide works well for the xA? I'm nervous to get in there, but I'm afraid of the winter starting and my fan going out on me.

RichBinAZ

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Had a quick look in the manual for the Xa and the units look the same.
https://www.scionlife.com/tech/manual/?manual=xa04_1504
I think the relays are under the hood and several may be the same. Might be able to do a swap with a similar power rated relay as a test

MrSwetz

Awesome, thanks Rich!

Also starting to think my problem may just be a loose cable or something with the Resistor, as when the Blower isn't working, if I open and then shut the glove compartment, it kicks right back in.

I'd also like to let you all know that Amazon has a really great deal on the blower motors, if you ever need one. Found it for $50ish bucks.

RichBinAZ

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Bumping this older thread as after 1 year, the blower has been intermittent on/off and now it is off completely.

So the lad has been driving around with the glove box out and the cabin filter out so that when the blower stopped working, he gave the fan wheel a quick spin with his fingers (dangerous) and it would start up again. Then finally it stopped doing that all together.

Today we took the fan out again and I measured the voltage across the connector to the fan and got nothing, with the fan speed selector at any value (ignition on - engine not running). Hooked up the fan to our battery charger and it fired right up no problem.

So looking at the wiring diagram, it would appear that the only suspects left are the heater relay, the fan speed switch and any wiring connections. The heater relay clicked on when switching the fan speed switch from off to any position, which confirmed a couple of circuits. At that point we had to put the car back together as it needed to be used, but we pulled the relay and drove to the dealer.

He did not have a new relay on hand and it was going to cost around $70 for one. Gasp
So we decided to test it.

Hooked up the 2 small outer contacts to the battery charger - with tape around them to avoid a short, then measure the resistance across the 2 fat terminals (power to the fan terminals) Off was infinite - On was zero Ohms. Perfect, that is what's meant to happen.

So we plugged it back in and the fan runs again - all speeds, no problem, just like new. Problem, what problem????

Is it the blower motor, is it the relay, the only way to test it is to take the blower connector off again and check the voltage with it in the working state. But neither of us has the energy for that right now.

It is a frustrating puzzle these intermittent electrical things. I added the 3 pages I wrote to try and do a diagnostic on this system here
http://s38.photobucket.com/user/Rich...ml?sort=2&o=12
which would have helped if I could find a smoking gun

2steptalon

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Do you have the values and cross points for the resistor using an ohm meter? Its hard to see in the pictures and I don't own a manual sorry.

Something is acting up and my fan won't work on any speed unless I give it a kick by the ECU. Works perfect as soon as it starts moving.

Thanks.

RichBinAZ

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I forgot to post up what we found to be a cure.
We replaced the little heater solenoid with a cheaper 4 pin solenoid we found on Rockauto.com
2006 SCION xB Blower Motor Relay
It seems to have worked and he has not been back to complain of the fan going off, in what, the last 6 months - so I think that is the cause.

Cause (this time) Solenoid on the blink.

In response to above issue - If you put the fan on HI you bypass the resistor block entirely - so it cannot be the resistor block.
Try the cheap solenoid (4 pin) and see if that does the trick.
See the write up for where it goes

RichBinAZ

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Another bump
The cheap solenoid has worked well for less than a year and the system is showing the same symptoms again. We will try to replace the solenoid with a different one and see how that goes.

Hopefully I will be able to take the cover off the current one to see what happened to it.

Edit -
Eased the cover off the solenoid, put it back in the socket and started the fan at the switch and the solenoid works. I can see the contacts closing when the fan is turned on. External testing proved the solenoid passes electricity.

So at this point I think it is the motor. We could get the motor to spin only when taking out the cabin filter and giving it a little spin, then it ran fine - so it is likely an issue with the motor's commutator ring. We ordered a new motor fan combo from rockauto.com and then after replacing the motor, I'll take the old one apart to see if anything is really wrong, or if there is a cheap or free fix that can be done.

If it turns out not to be the motor, then it has to be wiring glitch or a connector is not making proper contact. That will be very hard to find.

RichBinAZ

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I think we may have found the issue and it is the commutator ring in the motor coupled with the carbon dust from the brushes


After re-reading the box the fan came in, it looks like they sent us a fan that was common to a few cars including the xA - well it wasn't exactly the same. It took one small washer (3 places) on the inside of the plastic frame. One of the washers I had to file some flats on the outside of it to get it to fit in the slot properly. Use vice grips to hold the washer while filing.

I hope this fixes the issue, but who knows?!?!?

JRWooden

Rich: THANKS for the awesome docs!
All: I'm confused over one thing....

On Page 12 of Rich's tutorial the schematic shows just one relay that is relevant to the blower circuit
but
On Page 13 what I "think" I see it two relays being called out...
Relay D - under the hood
and
Relay A - under the instrument panel....

What did I miss?

Thanks,
Jim

RichBinAZ

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Well Searched - this is an old thread.
I'm having trouble remembering that far back. I think I was trying to figure out which of the 2 relays marked HTR actually turned the fan on and I really don't know what the other one does (rear window defrost???). But the A relay under the dash is the one.

The new fan we put in has indeed fixed the problem and has been running now since Nov 2014 (106K miles). He's coming up to 145K miles now.

Playing with the resistor block and relays didn't fix anything.

JRWooden

Thanks Rich!

Sorry not to reply right away, the "instant notification" feature I thought I had set wasn't working .........

Just because the motor seems a pain in the rear to replace (and some of the non-OEM replacements seem a little wonky in terms of fit) I'll walk through the other steps first and see what I can figure out...

I appreciate your help!

Jim