How to: A/C for your 3.4 swap
03-21-2012, 08:49 AM
#1
How to: A/C for your 3.4 swap
A/C information is hard to find, and scattered over several posts. So with summer coming, I hope this helps someone. I do not claim to know it all. I just searched to find all the info I needed, and efficively applied it to my swap. Recipient was a 95 4Runner 3.0 a/t. Doner was 1998 4runner 3.4 a/t. You wire colors and positions may vary a bit, but the logic is the same.
First decide if you want to use original 3.0 compressor or the newer one from your doner. Either one both bolts right on to the 5vz block. If you reuse the 3.0 compressor, all the factory lines will bolt on, but you must swap the clutch plate and pulley. If you use the 3.4 compressor it requires you to swap the top plate so you can be use you stock lines.
On my 1995 4runner, it came with a R134 system from the factory. It was still charged and presumably working so I simply unbolted the original 3.0 compressor and pulled it aside while completing my swap around it.
If you have a charged r12 system I would certainly go ahead and use it, and convert when/if you need to down the road. r12 is near impossibly to find and very expensive if you do happen to find it.
The original 3.0 compressor uses a v-style belt. The 3.4 motor uses serpentine belts. Therefore, you need to swap the pulley from the newer compressor to the 3.0 compressor.
Once you remove the 10mm nut from the center of the clutch, you'll notice that the outter hole is threaded. Use a slightly larger screw and put it back into the hole, and it pulls the outter clutch part off.
Take off the snap ring that holds the inner pulley onto the shaft
All taken apart
THIS. Don't lose this. It goes on top of the shaft to space the outer clutch from the pulley side. If you don't put this back in, the compressor will stay engaged all the time.
Put back together with 3.4 pulley and clutch
)
Now the compressor bolts onto the block. The lower line made contact with my upper control arm. I grabbed it and pulled on it and was able to gently bend it enough to remove the contact.
Now on to the wiring. The wiring will remain largely untouched. First we'll deal with the "A/C Amplifier to A/C magnetic clutch" is a B-W wire that comes from "IH2 15" (mine was B) on the old harness. This wire cooresponds to "II3 25" (mine was G-B) on the new harness.
If you are repinning your plugs, simply unpin wire out of "IH2 15" and insert it into "II3 25". If you are making a conversion harness, then solder a joint connecting the two wires. That takes care of the "magnetic clutch wire". And now when 12v is applied to that lead, the clutch will engage.
The last wire to deal with only concerns you if you originally had an automatic transmission. There is a Pink wire in "IH1 19" position that used to go to a temp switch on the old 3.0 motor. When the temps were normal, the switch was closed and completed the ground. When temps got too high, the switch opened, breaking continuity to the ground and shutting off the A/C compressor. You will simply ground this pink wire. I ran a leg out of the IH1 19 and put it under a screw beside the ECU on the kick panel.
I can't confirm for sure, but the 3.4 ECU should kick off the compressor if temp become too high, like the temp switch did on the old 3.0.
There are 2 more wires that will match up with your harnesses. They are the "AC1" and "ACT" wires. DO NOT DO ANYTHING WITH EITHER OF THESE Unpin them from your harness, you will not need either.
And that's all there is to it. I retained a completely stock system with minimal modificaiton. Only a pulley swap and 2 wires. I also used the stock A/C amplifier.
I have read several places that the tacho mod must be done before the A/C will work and that's NOT true. I have NOT done that tacho mod yet and it's working for me.
If your A/C compressor still does not come on, there is a 10 amp fuse located directly behind your glove box on the firewall. You must remove your glovebox. It's under a protective cap.
UPDATE 07/17/2012:
Some have reported that the compressor does not kick on at idle, or turns on and off randomly. If your A/C works at a higher RPM than idle (800+), but does not work at idle, follow THIS LINK RIGHT HERE and follow the instructions of NytWolf to adjust the low idle kick off on the A/C amplifier. Another direct link here: https://www.yotatech.com/forums/f160.../#post51944805
Feel free to comment, correct, or add info as needed. Stay cool yall (see what I did there?)
First decide if you want to use original 3.0 compressor or the newer one from your doner. Either one both bolts right on to the 5vz block. If you reuse the 3.0 compressor, all the factory lines will bolt on, but you must swap the clutch plate and pulley. If you use the 3.4 compressor it requires you to swap the top plate so you can be use you stock lines.
On my 1995 4runner, it came with a R134 system from the factory. It was still charged and presumably working so I simply unbolted the original 3.0 compressor and pulled it aside while completing my swap around it.
If you have a charged r12 system I would certainly go ahead and use it, and convert when/if you need to down the road. r12 is near impossibly to find and very expensive if you do happen to find it.
The original 3.0 compressor uses a v-style belt. The 3.4 motor uses serpentine belts. Therefore, you need to swap the pulley from the newer compressor to the 3.0 compressor.
Once you remove the 10mm nut from the center of the clutch, you'll notice that the outter hole is threaded. Use a slightly larger screw and put it back into the hole, and it pulls the outter clutch part off.
Take off the snap ring that holds the inner pulley onto the shaft
All taken apart
THIS. Don't lose this. It goes on top of the shaft to space the outer clutch from the pulley side. If you don't put this back in, the compressor will stay engaged all the time.
Put back together with 3.4 pulley and clutch
)Now the compressor bolts onto the block. The lower line made contact with my upper control arm. I grabbed it and pulled on it and was able to gently bend it enough to remove the contact.
Now on to the wiring. The wiring will remain largely untouched. First we'll deal with the "A/C Amplifier to A/C magnetic clutch" is a B-W wire that comes from "IH2 15" (mine was B) on the old harness. This wire cooresponds to "II3 25" (mine was G-B) on the new harness.
If you are repinning your plugs, simply unpin wire out of "IH2 15" and insert it into "II3 25". If you are making a conversion harness, then solder a joint connecting the two wires. That takes care of the "magnetic clutch wire". And now when 12v is applied to that lead, the clutch will engage.
The last wire to deal with only concerns you if you originally had an automatic transmission. There is a Pink wire in "IH1 19" position that used to go to a temp switch on the old 3.0 motor. When the temps were normal, the switch was closed and completed the ground. When temps got too high, the switch opened, breaking continuity to the ground and shutting off the A/C compressor. You will simply ground this pink wire. I ran a leg out of the IH1 19 and put it under a screw beside the ECU on the kick panel.
I can't confirm for sure, but the 3.4 ECU should kick off the compressor if temp become too high, like the temp switch did on the old 3.0.
There are 2 more wires that will match up with your harnesses. They are the "AC1" and "ACT" wires. DO NOT DO ANYTHING WITH EITHER OF THESE Unpin them from your harness, you will not need either.
And that's all there is to it. I retained a completely stock system with minimal modificaiton. Only a pulley swap and 2 wires. I also used the stock A/C amplifier.
I have read several places that the tacho mod must be done before the A/C will work and that's NOT true. I have NOT done that tacho mod yet and it's working for me.
If your A/C compressor still does not come on, there is a 10 amp fuse located directly behind your glove box on the firewall. You must remove your glovebox. It's under a protective cap.
UPDATE 07/17/2012:
Some have reported that the compressor does not kick on at idle, or turns on and off randomly. If your A/C works at a higher RPM than idle (800+), but does not work at idle, follow THIS LINK RIGHT HERE and follow the instructions of NytWolf to adjust the low idle kick off on the A/C amplifier. Another direct link here: https://www.yotatech.com/forums/f160.../#post51944805
Feel free to comment, correct, or add info as needed. Stay cool yall (see what I did there?)
Last edited by vasinvictor; 07-17-2012 at 08:46 AM. Reason: Corrected original post after working out the bugs
03-21-2012, 08:53 AM
#2
After a few hundred miles I can say that the compressor cycles correctly and blows ice cold. I have noticed that after hooking the A/C up, the truck idles a bit higher while the A/C compressor is off. When it is engaged, it idles perfectly. Only a minor annoyance, not enough for me to care about at this point.
I've cited several sources that state you don't need the 3.0 A/C idle up VSV hooked up and I can confirm it's not necessary for me either.
I've cited several sources that state you don't need the 3.0 A/C idle up VSV hooked up and I can confirm it's not necessary for me either.
03-21-2012, 09:16 AM
#4
.....
And that's all there is to it. I retained a completely stock system with minimal modificaiton. Only a pulley swap and 3 wires. I also used the stock A/C amplifier. I know Wabbit and others use the 3.4 amplifier, but I think they used those only in applications where the recipient didn't originally come with A/C.
03-21-2012, 09:20 AM
#5
My old brain doesn't focus like it used to 
I call myself reading it.
Just used 3.4 since we already had it but every vehicle has had factory air already. Perhaps it's a wiring thing but that's Jon's area not mine. I'll be sure to show him this and try it on my 88 3.4 swap.
Nice write-up.
:wabbit2:
I call myself reading it.Just used 3.4 since we already had it but every vehicle has had factory air already. Perhaps it's a wiring thing but that's Jon's area not mine. I'll be sure to show him this and try it on my 88 3.4 swap.
Nice write-up.
:wabbit2:
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03-27-2012, 08:29 PM
#8
Perfect timing I just hooked mine up the same way you did ... dont do anything with the act wire right? I'm gonna do a timing belt now that I got my swap dialed and everythings running great. Then I will add the ac belt and some vacuum and r-134 conversion kit and see what happens Thanks!
03-28-2012, 10:09 AM
#9
Correct, you can completely unpin the ACT wire from the plug. After several more miles, I observe that it idles perfectly with the A/C on. When the compressor is off, the truck idles a bit high. But it's getting hot, and I can deal with the minor annoyance in exchange for ice cold A/C. 
04-11-2012, 10:55 AM
#10
OK I finally did the tach mod so I need to comment on the idling status. When the compressor in engaged, the truck idles perfectly at 750 RPM. When the compressor disengages it idles about 1200-1250 RPM. About 500 more than it should be. This makes me think that the compressor idle up is activated all the time, rather than only with the compressor cycles. I am going to spend a little time with this and see if I can figure this out. I'm sure it's just another wire to add somewhere. If anyone else has any insight, please share.
04-26-2012, 10:07 PM
#13
So I decided to mount my compressor and figure out what I needed to do for the a/c wiring. I purchased my swap harness from Cliff and Justin @ TOS. It is not wired as you have specified (I checked and emailed them asking if they had done it correct)
They assured me they had and I just needed to jumper the compressor to suck a can or two through and all should operate after..
Well it did just that but if I pressed the a/c switch or turned the fan off and tried to turn it back on, the clutch on the compressor would not re-engage until I restarted the truck.
After a few choice words and a couple cold beers I attempted one last time and everything worked perfect! ICE COLD air.
I am stoked, especially with summer just around the corner!
They assured me they had and I just needed to jumper the compressor to suck a can or two through and all should operate after..
Well it did just that but if I pressed the a/c switch or turned the fan off and tried to turn it back on, the clutch on the compressor would not re-engage until I restarted the truck.
After a few choice words and a couple cold beers I attempted one last time and everything worked perfect! ICE COLD air.
I am stoked, especially with summer just around the corner!
04-27-2012, 08:29 PM
#16
Here are some pictures of the back of the plugs and how TOS wired it. Hope it helps! Let me know if you need better angles.
http://s133.photobucket.com/albums/q...ess/?start=all
http://s133.photobucket.com/albums/q...ess/?start=all
04-28-2012, 11:31 AM
#20
Calipatient, you are the man. Thanks for posting your pictures. It's helped me fix the idle issue and I report that the A/C works PERFECTLY now.
I have gone back and edited post #1 to have the correct information.
Here's the new rundown:
IH2 15 to II3 25- That's A/C Amp to Magnetic Clutch
IH1 19- GROUND THIS If you originally had an automatic, your harness with have this pink wire
DO NOT CONNECT AC1 OR ACT.
This is all it takes. Compressor cycles, and truck idles perfectly. No need for A/C idle up VSV.
I have gone back and edited post #1 to have the correct information.
Here's the new rundown:
IH2 15 to II3 25- That's A/C Amp to Magnetic Clutch
IH1 19- GROUND THIS If you originally had an automatic, your harness with have this pink wire
DO NOT CONNECT AC1 OR ACT.
This is all it takes. Compressor cycles, and truck idles perfectly. No need for A/C idle up VSV.
Last edited by vasinvictor; 04-28-2012 at 11:37 AM.
