Mechanics

EVAPORATION THERMOSWITCH LOCATED

1995 Subaru Impreza • 30,000 miles

Where is the Evaporation thermoswitch located so I can
check for the earth that comes from there and goes to the AC
relay that switches the relay.
Avatar
Eriksen
January 24, 2012.




Behind the right side of the dash.


Rivermikerat
Jan 24, 2012.
It will likely have a probe sensor that inserts right into the evaporator but the electronic portion should be on the outside of the case.


Wrenchtech
Jan 24, 2012.
Bith incorrect. It is a RHD car so in the passenger side footwell is the plug.

Damn ourput no good to pull in AC relay


Tiny
Eriksen
Jan 24, 2012.
Its in the passenger footwell!

Geez, I should be on this site.

Now the question is what is the reading on the 3 wires in the plug connected?

The white

The red

The Brown


Tiny
Eriksen
Jan 24, 2012.
Oh really.
The sensor by design has to read evaporator temperature so you tell me how it does that without being at the evaporator.


Wrenchtech
Jan 24, 2012.
You are correct, it is in there, but directly outside is the plug I was looking for ant the concern is that no earth on the white that woulds pull in the AC relay.


Tiny
Eriksen
Jan 24, 2012.
Wrenchtech, right hand drive. So everything is backwards. We'd have known that if told the vehicle was a UK model. I should have known seeing the word 'earth' instead of 'ground'.

Our reference shows different colors, but here goes: Green/Red=12V when on. I'm going to think that's your Brown.
Brown/White=Ground. Your White.
Red/Black=12V when ignition on. Your Red.

I've uploaded a copy of the schematic we have.
AD


Rivermikerat
Jan 24, 2012.
Thanks for the effort and reply but the "issue" of this story is the
Evaporation thermoswitch not pulling in the AC relay.
BrR (Brown / Red) 12v - Easy to trace.

White - MM (multimeter) Goes to the AC relay pullin coil and should be lesser potential difference than the BrY (Brown / Yellow)end of the pullin coil as the BrY has 12v when AC switch is turned on and you can trace it through the pressure switch where it changes to GY (Green / Yellow) the to the switch.

Thats straightforward and confirmed but the RED wire which looks like it feeds a signal to the amp in the Evaporation thermoswitch
seems to be the problem. When I measure the voltage with everything running it says 12 v, so how is the white cable supposed to have -ve voltage? And tracing the red cable you see it goes back to earth via Diode i17 and the fan switch.

So logic says its the diode. Will try finding it today, great fun in the sweaty humid weather here in Phuket, will also measure my friends Evaporation thermoswitch now that I found the connector. (Just ran my hand up under near the glove box a bit to the side and there it was.

Thanks for all the suggestions, any info on the Evaporation thermoswitch "AMP" would be helpful as I am just guessing how that works. In that I mean, it cycles the AC so it wont freeze up right? (So cant bypass it)

Also, the temp adjust switch (how cold you want it switch), I see it simply has a mechanical cable that moves a flap like something in the footwell. How does it adjust for compressor time engagement? Must have electrical cables as well, but I cant see any.
Thanks


Tiny
Eriksen
Jan 24, 2012.
The thermoswitch is a solid state transister that applies trigger ground to the relay to activate it.


Wrenchtech
Jan 25, 2012.
Apparently my answers aren't showing up.


Wrenchtech
Jan 25, 2012.

AD