2jzgte swapped sc300 AC problem
05-18-11, 11:22 AM
#31
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Alright, I'm gonna let the cat out of the bag since with the help of account2x for the relay info and info I found on the forum for the long discussed AC problem that pops up when using the Jdm aristo ecu. Yet few discussed how to fix it, but no one willing to paint a picture or give exact instruction of how to fix it, this will fix the problem assuming everything on the harness swap was done correctly at least for the AC wiring part. I drove around after wiring it up yesterday and everything is working as it should and cycles like it suppose to. Good luck everyone.
Best of all it's only a $3.45 fix
I wanna thank account2x for finding the relay as that was the part I was having a hard time finding the right one.
This is where to get it
Radio shack part # 275-233
It's called SPST 12 volt dc Reed Relay rated 0.5A 125VAC that's what it says on the box
http://www.radioshack.com/product/in...=under+%243.99
This is what it looks like thanks to account2x for these info
First you locate e-10 pin 34 which is the AC at the ecu and cut about 6" from the ECM, so now you have one part going into he ECM and one away.
Then locate e-10 pin 32 which is power for relay.
Here is how to hook it up, Going off of the picture above.
Top pin gets hooked up to power ( got mine from e-10 pin 32)
Left middle pin gets hooked up to hvac ( which is the e-10 pin 34 wire that was cut, the part going away from the ecu)
Right middle pin gets hooked up to acc power ( e-10 pin 32 again)
Bottom single pin gets hooked AC at ECM ( e-10 pin 34 wire going into the ecu that was cut earlier)
Now just clean up everything and shrink wrap all the the connections after it's been tested and enjoy your now working AC.
Anyone wanna send me a 12 pack of beer after all the headache trying to properly figure out how to fix this
enjoy everyone
Best of all it's only a $3.45 fix
I wanna thank account2x for finding the relay as that was the part I was having a hard time finding the right one.
This is where to get it
Radio shack part # 275-233
It's called SPST 12 volt dc Reed Relay rated 0.5A 125VAC that's what it says on the box
http://www.radioshack.com/product/in...=under+%243.99
This is what it looks like thanks to account2x for these info
First you locate e-10 pin 34 which is the AC at the ecu and cut about 6" from the ECM, so now you have one part going into he ECM and one away.
Then locate e-10 pin 32 which is power for relay.
Here is how to hook it up, Going off of the picture above.
Top pin gets hooked up to power ( got mine from e-10 pin 32)
Left middle pin gets hooked up to hvac ( which is the e-10 pin 34 wire that was cut, the part going away from the ecu)
Right middle pin gets hooked up to acc power ( e-10 pin 32 again)
Bottom single pin gets hooked AC at ECM ( e-10 pin 34 wire going into the ecu that was cut earlier)
Now just clean up everything and shrink wrap all the the connections after it's been tested and enjoy your now working AC.
Anyone wanna send me a 12 pack of beer after all the headache trying to properly figure out how to fix this
enjoy everyoneCongrat bro you one dedicated mother***
thanks for sharing.When i did the swap i used the JDM Supra 6 speed and 2jzge ECU and the AC worked great i didn't have to do anything i don't know what happened maybe i wired it up without knowing
I would love to share the info with the guys on here, if i had that issue i would share the fix with everyone on here.
again thanks for sharing
05-18-11, 11:28 AM
#32
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Don't have any pics besides the pic of the relay I bought, that's why I was as detailed as I can in the wiring instruction which is about as simple as it gets, since the pic of the relay is exactly how it looks and you can tell there's 3 pin on top side of relay and 1 in the bottom.
What are you looking for?
What are you looking for?
05-18-11, 11:36 AM
#33
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Thanks quicksc4. That only took 3 days for the swap once everything was here to wire up , installed, started.... And week to get the AC running properly. Who wouldve know the swap and combining of harness was the easiest part and AC was gonna give me the biggest headache. So much easier using usdm harness and ecu.
05-18-11, 12:28 PM
#34
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Thanks LExsingle for the write up! il send you a 12pack after ive done this. For the middle pins was the pins facing you or the other way? I already bought the relay im in the process of redoing my head gasket so i wont be able to test it yet.
05-18-11, 01:02 PM
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Soarer13oy- when your looking at the relay and pin towards you is how I was describing it, Simple.
Or if you have the package. Look at the diagram in the back. The two coil pin hooks up to hvac and power doesnt matter which way. And top and bottom which is N.O./ COM gets hooked to power and ac towards ECM, also doesn't matter which one goes to which as long as it's hooked up to top and bottom
Basic idea hvac and power activates/deactivate the relay, And AC wire towards ECM and other power all it's doing is allowing positive signal flowing to the ecu when relay is activated.
On this Sc swap as I've done 7 it's a 93 sc300 auto swapped with aristo 2jzgte. Running aristo/stock ge combined harness and aristo transmission and of course jdm aristo ecu.
Or if you have the package. Look at the diagram in the back. The two coil pin hooks up to hvac and power doesnt matter which way. And top and bottom which is N.O./ COM gets hooked to power and ac towards ECM, also doesn't matter which one goes to which as long as it's hooked up to top and bottom
Basic idea hvac and power activates/deactivate the relay, And AC wire towards ECM and other power all it's doing is allowing positive signal flowing to the ecu when relay is activated.
On this Sc swap as I've done 7 it's a 93 sc300 auto swapped with aristo 2jzgte. Running aristo/stock ge combined harness and aristo transmission and of course jdm aristo ecu.
Last edited by Lexsingle; 05-18-11 at 01:12 PM. Reason: Adding info
05-18-11, 02:03 PM
#39
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Soarer13oy- when your looking at the relay and pin towards you is how I was describing it, Simple.
Or if you have the package. Look at the diagram in the back. The two coil pin hooks up to hvac and power doesnt matter which way. And top and bottom which is N.O./ COM gets hooked to power and ac towards ECM, also doesn't matter which one goes to which as long as it's hooked up to top and bottom
Basic idea hvac and power activates/deactivate the relay, And AC wire towards ECM and other power all it's doing is allowing positive signal flowing to the ecu when relay is activated.
On this Sc swap as I've done 7 it's a 93 sc300 auto swapped with aristo 2jzgte. Running aristo/stock ge combined harness and aristo transmission and of course jdm aristo ecu.
Or if you have the package. Look at the diagram in the back. The two coil pin hooks up to hvac and power doesnt matter which way. And top and bottom which is N.O./ COM gets hooked to power and ac towards ECM, also doesn't matter which one goes to which as long as it's hooked up to top and bottom
Basic idea hvac and power activates/deactivate the relay, And AC wire towards ECM and other power all it's doing is allowing positive signal flowing to the ecu when relay is activated.
On this Sc swap as I've done 7 it's a 93 sc300 auto swapped with aristo 2jzgte. Running aristo/stock ge combined harness and aristo transmission and of course jdm aristo ecu.
I was asking because my shifter indicator lights dont work where my shifter is thats probably why my cruise control doesnt work. I just wanted to know if you can maybe send me the diagrams for the transmission wiring.
05-18-11, 10:53 PM
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If your shifter indicator is not hooked up correctly, the cruise control will not work. Because the cruise ecu look for neutral safety switch and if I remember it correctly it also checks to make sure it's in gear too. But neutral safety switch for sure. I'm not gonna have time to look thru the diagram. It'll probably be next week or this weekend before I'll get to it.
05-18-11, 11:05 PM
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I'm not sure what signal the vvti ecu look for... If it looks for a positive signal to turn on the ACMG then I would assume it will work, I would cut the AC wire 6" from the ECM. Turn the car on and AC on, then send a positive signal into the AC wire going into the ECM. If the AC compressor kicks on and start working, you can use the relay and it should make it work like stock.
05-19-11, 07:57 AM
#42
lexsingle we need to sum this up for all the n00bs:
the lexus HVAC unit grounds pin ACIN at the ecu, but the aristo ecu needs 12v at that pin. the A/C switch on the hvac unit only supplies a very weak ground, which can only trigger a "high sensitivity" relay.
both the aristo and lexus ECUs ground the AC relay to kick the AC compressor on, so you don't have to worry about that.
i'm glad you finally put an end to this question! a lot of people will find this helpful
the lexus HVAC unit grounds pin ACIN at the ecu, but the aristo ecu needs 12v at that pin. the A/C switch on the hvac unit only supplies a very weak ground, which can only trigger a "high sensitivity" relay.
both the aristo and lexus ECUs ground the AC relay to kick the AC compressor on, so you don't have to worry about that.
i'm glad you finally put an end to this question! a lot of people will find this helpful
Last edited by cartmill; 05-20-11 at 08:40 AM.
05-19-11, 10:44 AM
#43
Great info Lexsingle! Really nice write up
This might be a dumb question as I haven't looked at my ECU/wiring in a while, but is this getting the A/c functioning using the OEM A/C button rite? I too have JDM ECU and complete harness so I get how to hook up the relay. I guess I just have to locate the buttons wire/or wires then do those get hooked up to the relay to trigger the ecu?
This might be a dumb question as I haven't looked at my ECU/wiring in a while, but is this getting the A/c functioning using the OEM A/C button rite? I too have JDM ECU and complete harness so I get how to hook up the relay. I guess I just have to locate the buttons wire/or wires then do those get hooked up to the relay to trigger the ecu?
05-19-11, 02:18 PM
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Cartmill- great job summing up the basics as I was never great at explaining everything. You gave some great info in getting this to work. I just hope it helps all the diy people. Probably not gonna solve everyones problem as to some people have issues with wring to start with. If you wanna do another thread for sticky to make everything more clear, you are more then welcome to do so, as I just figure everything out and put it to test and posted results, it's always fun figuring things out. Now onto the next project. 
Sc51- yes once this is hooked up, the ecu does everything like stock. The climate contol unit ecu is the one controlling everything as to the compressor coming on and off. Also if you have the aristo ecu, I listed the exact pin that needs to be cut by the ecu, it's the smaller plug that's by itself on the ecu which is e-10 and pin 34 is AC input from the hvac. I didn't specify color due to some years might be different color wire but pin location is the same on the ecu. Good luck.
Stockhatch- thanks always appreciate the help. Just letting it out of the bag. Since it's a question that keeps coming up and solved, but no real answers even after it's solved besides the ecu needs different signal and relay, ended once and for all, I've done quiet a few swaps on these cars. I will post my results and how to do so at the place I got the most help and help others fix there AC problems. People like me are not about the money , but more about figuring things out and get a better understanding of things.
Sc51- yes once this is hooked up, the ecu does everything like stock. The climate contol unit ecu is the one controlling everything as to the compressor coming on and off. Also if you have the aristo ecu, I listed the exact pin that needs to be cut by the ecu, it's the smaller plug that's by itself on the ecu which is e-10 and pin 34 is AC input from the hvac. I didn't specify color due to some years might be different color wire but pin location is the same on the ecu. Good luck.
Stockhatch- thanks always appreciate the help. Just letting it out of the bag. Since it's a question that keeps coming up and solved, but no real answers even after it's solved besides the ecu needs different signal and relay, ended once and for all, I've done quiet a few swaps on these cars. I will post my results and how to do so at the place I got the most help and help others fix there AC problems. People like me are not about the money , but more about figuring things out and get a better understanding of things.
Last edited by Lexsingle; 05-19-11 at 02:23 PM.
