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AC bypass conversion to single wire and CCU bypass - complete

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20K views 35 replies 17 participants last post by  1funryd  
#1 · (Edited)
Updated: 3-25-2021

**New video explaining it better from MustardCat:


I have finally completed the AC conversion for the H22/23 swaps. This is for those who want to go with the OEM AC compressor for the H motors. It is actually easier than we initially thought and has been done and running in my H23 swap. Read below and enjoy!!!

Ok let me explain it.










1. You need to bypass Clutch Relay B under the Battery try, there are two relays. Relay B has the solid colored wires so to do this you need too:
  • Cut the Red wire and Grey wire on Relay B Butt connect them together with insulated butt connectors to be heat shrank by heat gun. For weather proofing. You have now bypassed Relay B.
  • Cut the Yellow/Blck wire on Relay A side wiring, this wire is a hot wire that needs to be connected to a 12v ignition switched connection or just run a jumper wire straight to the ignition harness under the dash in front of the fuse panel on the drivers left leg side. I just ran the jumper wire along the front of the battery along the side of the engine bay fuse panel zip tied it to the high pressure ac line that is there and the behind the Vaccum box along the fire wall and into the rubber gromet that is right behind the gas pedal and straight to the fuse panel and plugged it there.
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  • The 1st accessory wire is the fat Yellow/Blck wire on the ignition wiring. There is no need to undo the dash this wire runs along the bottom of the fuse panel coming from the ignition. But if you need wiggle room then go ahead and drop the under dash panel. Tap that wire with those female electrical T-tap connectors, you will need the yellow T-taps on this wire because it is a thick guage wire.

  • Next we are going to connect all the hot wires together since they all need the 12v ignition switched power source. Cut the Red/Yellow wire on Relay A as well, then splice Yellow/Blck and the Red/Yellow together so they are all connected because they will be supplied by the same jumper wire to the 12v switched source.
  • When you butt connect all these wires together please get the insulated heat shrink butt connectors so they are weather proofed, you are not going to want to mess with these wires again.
2. Next we move on to the AC Compressor wiring.
  • First cut the harness off of the original B20/21 compressor, this is crucial because it already contains the diode that is going to be needed to reduce the electrical back surge to protect the ac clutch relay.
  • Cut as close to the compressor as possible, leave about at least 2" left at the compressor for possible reconnection later should you choose to.
  • The harness from the compressor will have a Red and Brown wire, and a Green and White wire, then the one wire left which is the Diode wiring. Connect the Red and Brown wire together, then cut the Green and White wire as close to the harness as possible and electrical tape it up, it is not going to be used.
  • The diode wire will have a connector on it you will want to cut off the the bullet style male connector and connect it to the one single Red hot wire on the H22/23 compressor. This will keep the Diode inline of the hot wire on the H compressor.
  • Clean it all up and make sure everything is nice and taped up and insulated.
3. Now to move on to the ECU side. The H22/23 ECU's control the AC clutch, and Condensor Fans and the throttle response for adding fuel to the system once the compressor kicks on so that it does not stall.
  • First take off the glove box, and unplugg the CCU unit, it was the control module that everyone always needed to resolder due to corroded solder points and the weak link in the OEM AC system.
  • Now cut the Red/Blue and Red/Yellow wires behind the harness plug and butt connect them together, and that will bypass the AC Control box or otherwise known as the CCU unit.
  • Now you leave the plug unplugged from the CCU box, you have now elimitated the CCU unit. It will no longer be needed.

Here is picture of the CCU unit location....(borrowed someone elses pic..)
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You are now electrically ready to pluge it all up and turn it all on. I recommend you do not tape everything back up until you have tested your connections, or else you will have to take all apart again.


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You will need to get custom AC lines made to route the lines properly to clear the motor should you need to pull the motor at a later date. Once make those lines and vaccum the system and the refill it, it will cost you alot of money to refill it again should you pull the lines back off if you need to pull the motor out. So keep that in mind when having them made.

And make sure you have enough of the tubing coming out of the ac compressor so your local AC shop can have enough material to work with or they will charge you more for adding and welding in more aluminum ac tubing.

Here is a picture of how my lines are run. I will be redoing the low pressure side which runs along and over the tranny.



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Enjoy and happy luding!!!!:p
 
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#3 ·
fuckin tops!!!
i need to do a writeup on the ac setup im going to have for my megasquirted lude, i need to wire the ac system as if it was in a carbed lude and then build a pulse width modulation control circuit to control the idle valve so it opens when the ac kicks in! will do this post once i get it going!
 
#4 ·
friggen genius!!! i now have this thread bookmarked for when i do my H swap.
 
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#5 ·
Wow good work man. H22 swap looks better now than before. Did you use the stock condenser and drier?

Hey I noticed the suction line runs in front of the header. I would wrap that line in something to insulate it from the exhaust heat. btw, are you using R-134a?
 
#6 ·
TripleLude said:
Wow good work man. H22 swap looks better now than before. Did you use the stock condenser and drier?

Hey I noticed the suction line runs in front of the header. I would wrap that line in something to insulate it from the exhaust heat. btw, are you using R-134a?
Click to expand...
1. Yes stock condensor, and drier but I bought a new one and replaced it and o-rings(a must).

2. Nope, I am using R12, much cooler and expensive, but I am old school like that.

3. That line is just fine, the OEM line runs the same route, and there is no heat catching it, I have run the setup for a week and no issue.

I lost cooling just earlier this week, but I believe it to be my used AC compressor, I am heading back on Saturday to see if we can salvage it, if not I will have to come out the pocket and by a new one.
 
#10 ·
hondalude89 said:
Could it be that your AC failed because you are using R12. IIRC, H22/H23 AC systems use the R134a. Maybe that f-ed up your compressor seals. Just a thought.

-Carlos
Click to expand...

No my AC guys notice that when we got the system working the clutch would slip and then work.

We kept testing it, but it did not do it again. However since this is a custom swap, and I used a used compressor, there are some things working against me.

The system held vaccum when tested, and then it held with the system full with R12. And this compressors are made to handle both R12 and R134.

It will be on the lift tomorrow and we shall see whats going on.

But other than that, we have SOLVED AC!!!!


If you were hesitant to do the swap before, now you have no reason to hold back.

Powersteering - check
Cruise Control - check
AC - check
 
#12 ·
Tanx, but I must give credit to one of our other H swapper Mr. Osvaldo516.

He was the one who went digging and trying different things, then I when I was research the net, I found a forum for Auto Airconditioning and happened to notice that the thread that I googled had a familiar name.

And guess who it was, our friend Osvaldo516 doing research all the way in Afghanistan while on deployment.

So I joined in the conversation and we were enlighted by two members who gave us a direction to with our problem. And walla!!! We tried what was suggested and bam we got it to work!!!

I just did the leg work...hehe!!:-D
 
#13 ·
sean, I finally was able to get my internet going for a bit, please email the pics since I can't see them unless you use imageshack. about 50 days until I get back from deployment!!!
 
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#15 ·
got them, thanks...
could you email me some pics of the CCU bypass as well
 
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#16 ·
AC saga continues...

Well I took off the AC compressor or actually just unbolted it so we could get to the pulley and clutch.

The feeler guage was at 26thousands loosley, so the clutch was slipping so my ac guy pulled the pulley and took out the las shim which was pretty thin, so he ground down the back of the pulley to get more shaved off so the pulley could grab.

After 2hours of taking things off and putting all back on, still no cold air. Come to find out I have a leak!! arrrgggg...

So he puts more R12 in and the dye but then he notices something and tells me to shut it off. He checks his guages and tells me that he believes the expansion valve is stuck. ahemmmmm.....

So now I will not use my ac until next Saturday and I have to order a new expansion valve, and evaporator core since we will be in there and since the OEM is still original and this is a 23 year old car.

So that is were were are at now. update will be next weekend.

AAhhhhhh!!! At least my ac compressor is working fine. I just happens when you fix one thing, another pops up. LoL!!!:nervous:
 
#17 ·
wow man sorry to hear about that, but hey at least you will have a brand new system that will last you for another 23 yrs
 
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#18 ·
Awesome sean, now when I get a bit more cash in my back pocket (which should be before the next aussie summer) I can do this to keep the gf happy..... then all I need is Cruise Control and she's like normal.... but keep an eye on it the next year Sean..... just u watch :)
 
#19 ·
Sean, I know the feeling. I really really do. I fixed my AC for about two weeks, then the discharge valve leaked. Replaced and it lasted only a little while when something else leaked. However, I'm using R-134a, which is thinner and more likely to leak.

In any event, I wish you luck.
 
#20 ·
TripleLude said:
Sean, I know the feeling. I really really do. I fixed my AC for about two weeks, then the discharge valve leaked. Replaced and it lasted only a little while when something else leaked. However, I'm using R-134a, which is thinner and more likely to leak.

In any event, I wish you luck.
Click to expand...
Thanks bro, I knew I would be dealing with gremlins, but that is just how it goes when we own classic car and keep using it for daily driving.

And to put things in perspective, the lude had no major issues until after 5 years. Then timing belt snapped, powersteering line blew, overheating issues due to old hoses, etc..

These cars are very reliable, but with any car and especially a 23 year old car you have to put work into it to keep it going. :tounge:
 
#23 ·
Update.

big_boi_lude said:
This makes the H swap flawless now, upgrade in power that no longer affects the comfort, mine only down side to the H22 swap now is I want to lower the car more but Im already on my second set of HyTech reps :(
Click to expand...
Yes this does, it makes the swap complete. And to solve your downpipe issue, you need to get the AZ Race Traction Bar with the skid bar, it will save your header and oilpan.


On another note, I realized I did not update everyone, but my H swap AC conversion is complete and working.

The issues was the expansion valve and old Evaporator core. I changed the Evaporator core, expansion valve, and the drier.

Once everything was installed, we vaccumed and charged the system again, and Bam!!! We got AC. I have been running with AC for over two months, and things are going good still.
I am not using R12 yet, I am using something called Enviro something. It operates at a lower pressure and is just as cold as R12. We are running it in the system in order to see if the system leaks so we can find the leak and seal it.

But so far no leakes. I will be going back to have him vaccum the system and then put in R12.

First H swap to have fully functional AC. Yay!!!
 
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#27 · (Edited)
I was reading osvaldo516 's old threads back from 2009 on this subject and this cleared up a HELL of alot of confusion haha. props to both osvaldo516 and 1funryd on tackling this.

i looked in the FAQ for this thread and did not see it. this 100% should be added to the FAQ under at least ONE of the ENGINE subjects
 
#28 ·
definitly should lol

so question is can I just use r134a not sure I can find r12 here and I just remember last time I regased my dd 3rd gen the ac broken right after may have sth to do with it, didn't ask them what they use though.

and I want to keep the dcc, will this still work?
 
#32 ·
DCC shouldn't be affected. and the type of gas will depend on your local environmental Laws. I know some old early 90s freeon is no longer legal here so we're forced to use some new thing. (sorry don't have exact names/numbers)
 
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