Franken-A/C (92 Loyale, 98 EJ22 engine, 93 EJ22 AC parts) need help!

[climb1028]

https://drive.google.com/file/d/0B3h8j6sXR813blBiY05haDVJcWc/view?usp=sharing

 

I have a 98 EJ22 in my 92 Loyale Wagon. I put in a D/R tranny, gave it a 2-4" lift and just last week put on the stronger springs that JesZek suggested along with all new struts and all new 1/2 shafts. She's running pretty awesome!

But first! I need my AC for the upcoming hot summer!

I scavenged all the R-12 parts out of a 93 Legacy (compressor, compressor bracket, tensioner pulley, lines, receiver/dryer/pressure switch) and paid Mac's Radiator here in Portland a large chunk of change to mate all the fittings together and integrate it into my Loyale (so it hooks up to the Loyale condenser and evaporator. They also ran through the system, changed out O rings, flushed and pressure tested it. They said it's all clean, flushed, the compressor seems to work fine, the system holds pressure and they also replaced the drier. Unfortunately they wouldn't put R-12 in it until I re-installed the Sub Fan and got it wired correctly. 

So I've spent the day searching for all the different wiring diagrams for each donor car and locating most of the necessary wires from the EJ ECU.

I already have 2 fan relays that I set up. Plus 2 slim fans, pulling from the inside of the radiator. The main fan is switched on with Pin 74, a Red/Blue wire that goes to ground when the engine gets to about 90 degrees C. I was told the sub fan is switched on with Pin 73 after an even higher temp is reached. Pin 73 is a Green/White wire that I tried to use for my 2nd fan. It never seemed to work no matter how hot I got the engine so I ended up wiring a toggle switch next to the steering column for its relay.

My understanding now is that it (Pin 73) is grounded when the A/C is turned on. My goal is to get the A/C wired up properly, so that the ECU does what it needs to do: Kick up the IAC for 1/2 a second and then switch on the A/C compressor relay and fire up the Sub Fan simultaneously. I would like to run the compressor trigger line on the A/C relay through the pressure switch on my drier so that it has that as a backup safeguard as well. I will also run the toggle switch to the A/C relay ground so I can keep manual control of the 2nd fan as needed.

Here are my questions:

Where on my 92 Loyale can I find the wire that is activated when I press "Defrost" or "A/C" on my dash? Is it grounded or hot when I turn on the A/C? If it's hot like I imagine, then I want to run this +12v wire to the hot on my A/C relay, and to the compressor trigger wire via the Pressure switch and A/C relay contact?

I am assuming that Pin 31, Blue and Orange will provide the ground to fire the A/C relay and turn on the compressor. 

I'm also assuming that Pin 60 receives a +12v signal from my A/C "on" hot wire when I hit the A/C buttons and this gives the ECU the heads up that I'm calling for A/C so it can do it's job. Right?

So, yeah, my biggest questions are: Where can I find the A/C wire on my Loyale? and is +12v the correct voltage to input into Pin 60 on my ECU when I call for cold air?

Hopefully my link above shows the picture I drew of what I intend to do. Can anybody confirm or deny my ideas??

 

 

[MR_Loyale]

On the passenger side firewall near where the lines go into the evaporater there is a fuse holder for the AC circuit.  Not sure if that is what you are looking for, but that might be a place to start tracing with a test probe.

[climb1028]

No luck.

I found a wiring diagram for my 92 loyale MPFI ECU and noticed it had a Blue/Yellow wire that went from the ECU to the compressor and also to a Fast Idle Adjustment Device solenoid. I was all excited when I found this Blue/Yellow wire (and a black ground wire) near the passenger side firewall in my engine compartment but it appears to be ALWAYS +12 volts when the car is ON. I get no change when I select or deselect A/C on my dash. 

There are 2 relays over there as well. I tested one and it didn't show any change when I selected A/C.

I found 3 wires near the battery that I originally thought were for the stock A/C compressor: a blue wire that is always on +12v, and a green/white wire paired with a red wire at a connector that are both on +12v when the car is ON but both drop down to 0.22v when I select A/C on my dash... close! But opposite from what I'm expecting. 

I'm trying to find a wire that gets hot when I select A/C. Is there such a wire????

Or am I fundamentally mistaken about how I imagine things are working here? Does the compressor indeed need a +12v signal to turn on? Does my 98 ECU indeed want +12v signal input to Pin 60 when I select A/C??

I'm going to continue searching my Loyale over for a wire that gets hot when I select the A/C.... any help would be appreciated!

[DaveT]

There should be a wire that goes hot only when ac is on. A factory service manual with full schematics would probably help. When I got my 86 gl wagon ( same as loyale) The ac compressor was shot. I discovered that the ac compressor was always engaged. Found that someone had rigged a wire to force it always on. Don't know why. After un modified, the ac switched like it is supposed to.

[climb1028]

Thanks for the tip DaveT. After testing the two relays in the rear passenger corner of the engine compartment I think I found a suitable wire: it's a rather thick Green/White wire that seems to energize to 12v when I select any of the buttons on my climate control panel. I thought that A/C only was called for when I selected Defrost or A/C-A/CMax, but I will settle for the compressor turning on anytime I select air in the cabin. As you will see on my wiring drawing I plan to have a manual toggle switch under my dash to turn off A/C in case I want air to blow but don't need it conditioned. 

If anyone has any idea whether I'm correct with my Green/White wire choice as the A/C on trigger wire, whether my wiring diagram looks correct (I feel like I need some diodes in there somewhere but I'm not sure where to put them), and can anyone confirm whether pin 60 on my 98 Legacy EJ22 ECU needs to see +12v when the A/C trigger wire is hot and whether pin 31 goes to ground to turn on the actual compressor - much appreciated!!

[maozebong]

The ac switch should be mounted on the driver's side of the HVAC box. It is what controls the ac relay, and probably what you want on a toggle.

[MR_Loyale]

Ac is also used to dehumidify.

[climb1028]

Thanks guys. I can make everything just run off of relays, but I would rather have ECU integrated into the system so it can do the job of increasing idle when the AC is on and/or shutting off the AC under Full Throttle.

I know the AC dehumidifies I just thought it only ran the compressor for defrost and for AC (cold air). Is it supposed to turn on the compressor ANYTIME I call for air in the cabin?

My question about the ECU inputs still remain. Does Pin 60 need to see 12 volts when I call for AC and does Pin 31 ground the relay for the AC compressor, while Pin 73 grounds the relay for the Sub Fan? Am I missing anything?

I just can't seem to find the table for my ECU (98 EJ22) that describes the operating voltages for all the Pins...

[climb1028]

OK! Success!

After a couple full days of fiddling with everything I finally just sacked up and wired it to the ECU and fired it up.

After a couple of snafus it all ended up working perfectly! The ECU sees my call for AC, bumps up the idle to about 1000rpm and a half second later gives 12v to the compressor and turns on the sub fan. Sweet!!

I used fuses for all the AC wiring, I ran the power for the compressor through the pressure switch on top of the dryer/receiver and I mounted a nice fused bus bar and mounted the relays next to the battery. It ended up looking nice and tidy and I have an appointment with the AC shop tomorrow to get it charged up with 2 lbs of R-12! So stoked!! Just in time for summer!!! I'll try to post a picture of the final wiring schematic that I ended up wiring in as well as a pick of the engine compartment. It's not the most sexy thing ever but I'm pretty excited!

Thanks for the help guys.

Now I'm just waiting for my buddy *ahem!*PatrickAnderson*ahem!* to finish the 6 lug hubs and my Suby will be COMPLETE!!

Ok, never really complete... tons more that I dream about... for another day. Maybe this fall after I'm all fat and happy from a summer of driving around with cold air.

[climb1028]