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L300 a/c - compressor wires

Posted: Wed May 11, 2016 9:30 pm
by ypelex
Admin: This thread has been cleaned up for the Technical Reference Library. Original thread is here: http://www.delica.ca/forum/viewtopic.php?f=6&t=17568

Hi,

I can't seem to find where to connect the 12V wire that should go to a/c compressor. Mine somehow came off - not connected any more, compressor won't engage.

Tested - the wire shows 12V when a/c switch is pressed.

Attached 2 pictures ... mine looks the same. Strange the wires attached to the compressor only connect to (-) .

Where do I connect the (+) 12 V wire ? Puzzled....

Re: L300 a/c - compressor wires

Posted: Wed May 11, 2016 9:41 pm
by ChuckBlack
bottom LHS of the compressor,,, mine is located there!!!

Re: L300 a/c - compressor wires

Posted: Wed May 11, 2016 9:50 pm
by ypelex
Not sure why I can't attach pics ... anyway... mine looks like this one for sale - it has 5 pics..

http://www.ebay.co.uk/itm/251997081762? ... rmvSB=true
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Admin: added a locally-hosted copy of referenced picture.

I don't see another socket for the (+) wire.

The one attached is (-) as I figured out ...

Re: L300 a/c - compressor wires

Posted: Thu May 12, 2016 4:20 pm
by Growlerbearnz
The long lead from the compressor clutch should connect to a black with white stripe wire. It comes out of the wiring loom at the same point as the idle-up vacuum solenoid wires (one of which is also black with white stripe. Easily confused with battery (-) wires, which are black with white stripe *plus* red spots. Thanks Mitsubishi.)
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Compressor.jpg
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The aircon compressor is run by the time delay relay behind the glove box- it delays compressor turn on by about 4 seconds, presumably to prevent any chattering. If you test the black wire with white stripe you'll find it's earthed until the time delay relay turns on, and then it goes to +12V.

Interestingly (if you're a geek like me) the aircon cutout switch on the injection pump (black with yellow stripe wire) also triggers the time delay- when you floor the accelerator the aircon compressor only cuts out for 4 seconds. Enough time to change a gear and spool up the turbo, I guess?

Re: L300 a/c - compressor wires

Posted: Thu May 12, 2016 6:12 pm
by ChuckBlack
Jizz you're into some deep shit buddy!

Re: L300 a/c - compressor wires

Posted: Fri May 13, 2016 10:01 am
by ypelex
Thanks a lot, Growlerbearnz!!!

You made me realize the cable I am chasing is not going to compressor.
It is a part of the A/C as I only see 12V on it when a/c button is pushed on. It is probable going to one of the relay / switch ?

Where does this one connect to ?

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L300 a/c - compressor wires

Posted: Fri May 13, 2016 3:20 pm
by Growlerbearnz
TL:DR; Connect that one to earth (chassis, battery(-)) if you want your AC to run.

More comprehensive answer;

Blue with yellow stripe wire? That should connect to a thermo switch in the radiator hose stub. The thermo switch should be earthed unless the coolant temperature exceeds 115C. When the thermo switch opens it disables the AC. If that wire isn't connected to earth, your AC will think the water temperature is too high all the time and won't work. On my engine the thermo sensor failed, so I just replaced that spade terminal with a ring terminal and earthed it to the engine bay (the screw that holds the idle-up solenoid in place is convenient).

There should also be a black wire coming out of that sleeve alongside the blue/yellow one. The black wire goes to a second thermo switch in the same area, and turns on the radiator condenser fan if coolant temperature exceeds 105C whether AC is on or not.

If you have both thermo switches (and both wires), you'll need to put a multimeter on them when cold to figure out which one is which. Blue wire with yellow stripe goes to the one which is earthed, black wire goes to the one which is open.

Download an aircon manual from here: http://www.delica.ca/forum/viewtopic.php?f=17&t=10087. A guide to thermo switch testing is on page 55-43, but a warning: that manual is for a Pajero and is not quite correct for our engines. What the manual identifies as "thermo switch 1 (for AC cutout)" is, on our engines, used to drive the temperature gauge and glow plug CPU. Don't mess with that sensor, it gets brittle and replacements are super expensive.

**UPDATE** the correct L300 AC workshop manual is here (http://www.delica.ca/forum/viewtopic.php?f=17&t=17809) as part of the complete L300 manual.

On our engines both thermo switches should look more like "thermo switch 2" and be in the radiator hose outlet stub.

Re: L300 a/c - compressor wires

Posted: Fri May 13, 2016 4:44 pm
by ypelex
hi Growlerbearnz,
This is promising .... and scary :-)

do I understand this correctly that compressor will get the (+) over engine body ... that's why the other wire on it seem grounded ?

So my hanging wire is yellow & blue.... to it should go to thermo switch which is grounded (allows current over body to the compressor unless temperature riches high) , right ?

Any chance you can send me a pic of that to be sure (blue & yellow wire connecting to the thermo switch) .

Will check it tonight ... or tomorrow morning as it is stiull Fri the 13th here ... :-)

Y

Re: L300 a/c - compressor wires

Posted: Fri May 13, 2016 5:58 pm
by ypelex
UPDATED

is this the one (thermo switch) where I need to connect the wire to ?
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After looking at the PDF & a few other pictures I had no doubts that's the thermo switch.

Attached my wire to it & compressor is back in business. Suspect it was disconnected last November when all the belts +water pump were replaced & never connected back until now.

Thanks everyone who reponded !!!


PS. Still a bit puzzled how is it possible to connect +12v to engine body to engage compressor :-), but my electrical skills are at the high school level.

Re: L300 a/c - compressor wires

Posted: Fri May 13, 2016 10:20 pm
by Growlerbearnz
Yes, you are correct. The compressor gets (+) through the black/white stripe wire (long wire from the compressor), then to earth through the short wire on the compressor.

The thermo switch in your photos looks like the correct one to connect the blue/yellow wire to. If you can test the thermo switch, check that it is connected to earth, but you won't harm anything by just connecting the blue/yellow wire and seeing what happens.

I can't send you a photo of my own blue/yellow wire because I don't have a thermo switch any more, sorry :-)

Re: L300 a/c - compressor wires

Posted: Fri May 13, 2016 10:33 pm
by ypelex
Thanks again , Growlerbearnz !.

Updated my previous post, but will confirm here again that connecting that wire to the switch made the trick - all good (cold ) now with A/C.

:-)
Y

Re: L300 a/c - compressor wires

Posted: Sat May 14, 2016 5:27 pm
by Growlerbearnz
Great!

The +12v wire to the compressor doesn't go straight to earth/engine body, it first goes through a coil behind the pulley. If you look at the compressor with the engine running but AC off you'll see part of the pulley spins, but the steel disc at the front stays still. When you turn on the AC the coil creates a magnetic field which attracts the disc to the pulley, and starts it spinning, running the compressor.
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L300 a/c - compressor wires

Posted: Sat May 21, 2016 7:34 am
by ynwa
Growlerbearnz wrote:Great!

The +12v wire to the compressor doesn't go straight to earth/engine body, it first goes through a coil behind the pulley. If you look at the compressor with the engine running but AC off you'll see part of the pulley spins, but the steel disc at the front stays still. When you turn on the AC the coil creates a magnetic field which attracts the disc to the pulley, and starts it spinning, running the compressor.
Compressor copy.jpg
Interesting side bar, my bus has a wire spliced into tue ground side that ran to a toggle hacked into the side of the shifter housing.

Had no idea what it was until recently. I guess I'll find out when i try to run the ac. :) seems my stock switch may be somewhat buggered if I'm reading into that right.

Good post.

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