Hi,
I just took a closer look at the fuse box located in the Engine Compartment of my 2005 xB.

Perspective:
Standing at the front bumper and looking at the engine compartment square on.

What I see:
The nearest edge of the box has THREE RELAY Slots running from left to right.
HOWEVER, there are only TWO BLUE relays installed.
They are for HORN and EFI .

There is room for a relay labeled:
A/C
MG

What does this missing relay do?
Should I be concerned? :?

Curious minds want to know.

Thank you.

 

I'm gonna guess that your ride doesn't have Air Conditioning, as the missing relay is for the Air Conditioning Magnetic Clutch (A/C MG).

 

That would make sense if there was not an A/C Button (with light) on the dashboard.
But there is one, and the light goes on when pushed in.

However, this would explain why I hear no engagement of A/C when the button is pushed.

Think I'll open the hood and take a look around.
....
Just took a look.
I think I found the A/C compressor and at least one high pressure black hose going to the front of the car in front of the radiator.

Is it the A/C unit about a foot below the alternator?

 

Yes

 

I thought the xB A/C was a different design. It spins continuously and has internal valving instead of the clutch on the pulley? If so, then there wouldn't be a relay?

 

yea ive actually wondered this since i saw one day that labeled fuse and yet it wasnt there.... any more info?? does scion/toyota sell one that should be there???

o and are all xB's like this without that fuse/relay?? b/c i bought mine new and it wasnt there....

 

That is a left over slot from back when the bB had an A/C clutch. xBs no longer use a compressor clutch as stew32 stated. Nothing to worry about.

 

THANK YOU!
Being the "slightly" picky-picky sort of person (details- details) I was beginning to worry about this discrepancy.

Now I can sleep well tonight. :D

 

NP, I'm the same way when it comes to all my vehicles.

 

Sorry to dig up an ancient thread; but after days of searching, this is the only place I have found this information.

If there is no clutch, how do you get the system to activate (after vacuuming), to pull in more refrigerant? I got it normalized to equal the can pressure, on both high and low sides. But it is not creating low nor high pressure, on either side, so it will not pull in more refrigerant. And the low side line is not getting cold at all, either, of course.

 

If the AC doesn't have a clutch, then it likely has a "variable swash plate pump design" (<--google that) where I think they use a solenoid to change the swash plate angle.
So there should be an electrical connection on the pump that activates the solenoid.
There is likely a fuse somewhere.
I have heard people say it may work after a tap with a mallet, or it cant be fixed without replacing the whole pump.
Not had this problem yet though.

 

Thanks for the response! By pump, I assume you mean the compressor?

Is there any confirmation (or even support) anywhere that this compressor does not have a clutch? This is the only place I have found this mentioned.

 

I don't know how to tell if its one or the other. Can't find any definitive answer from Toyota or a reputable source.
But there is this...
https://parts.earnhardttoyota.com/oe...EtNWwtbDQtZ2Fz

and this
https://www.toyota-industries.com/pr...ssor/variable/

The "VAR" implies variable and the second link shows what their variable compressors are. That link says they started mass production in 1996, so odds are they are in all of todays cars except for the electric models and perhaps hybrids

Neat video on this page of how it works at the bottom of the page
https://www.toyota-industries.com/pr...ressor_kind_1/

 

Thanks for all of the great info!

Looks like the variable swash plate compressor doeshave a clutch, though, if I'm reading this correctly?

"Based on the one-way swash plate design, Toyota Industries began mass production of the world's first external signal-controlled compressor with a one-way swash plate, continuous variable displacement, and onboard clutch in 1997."

I'm in a difficult predicament of there seeming to be no relay/fuse for the AC clutch, and there being no evidence that the compressor doesn't have a clutch, except for one mention on this thread.

 

The variable swash plate compressor doesn't need a clutch to work.
With the plate perpendicular to the shaft axis, it doesn't pump anything, while the shaft is rotating.
It's only when the plate tilts that it starts pumping. The more it tilts, the more it pumps.

My guess is, that if you don't have a clutch relay, there is no clutch, but there is an electrical supply to the compressor to tell it what to do.
That probably comes from the main engine computer. I don't have a schematic to figure that out