1JZ swap/SC400 A/C not kicking on
#1
1JZ Single SC400
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1JZ swap/SC400 A/C not kicking on
I have read about the Ac problems after this swap, but every thread I have found, everyone was using the Aristo or Soarer factory ECU. After the research on here the Aristo needs a relay wired in that controls the signal by a 12 volt source, not by a GROUND. The Soarer requires a ground. The problem I have is that I am using a AEM V2 from DM. The pin layouts on the factory 1JZ harness side says pins A17 is the A/C clutch relay and pin A27 is the A/C switch signal. My problem is that the patch harness from DM didn't come with these pins and they have this puddy stuff to seal up the other connections. I did go into the settings in the AEM and turn on the switched output for the A/C to work. When I did this the idle of the motor went up but the compressor didn't kick on. Thus now I know why, there is no signal to it.
If anyone is using the AEM, does this info sound right?
The mechanic was pretty sharp on his wiring skills, he did jump the relay and the compressor did kick on, but I want it to work like factory. He also stated it blew ice cold and found no leaks.. which is good. We further discussed the wiring and he said that A17 is a white wire on the 1JZ engine harness side, and the A27 is a blue/red, which supplied the 12 volts.
Can someone kinda get me started in how and what to cut and splice, just to get me started?
Thanks guys! Its starting to get real hot here in Alabama..
If anyone is using the AEM, does this info sound right?
The mechanic was pretty sharp on his wiring skills, he did jump the relay and the compressor did kick on, but I want it to work like factory. He also stated it blew ice cold and found no leaks.. which is good. We further discussed the wiring and he said that A17 is a white wire on the 1JZ engine harness side, and the A27 is a blue/red, which supplied the 12 volts.
Can someone kinda get me started in how and what to cut and splice, just to get me started?
Thanks guys! Its starting to get real hot here in Alabama..
#2
Lexus Champion
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You hit it on the head. Just add the wires into the patch harness to connect A17 to the AC relay output from the AEM, and pin A27 should go from the HVAC controls to the signal IN on the AEM.
I don't understand why your engine would idle up without an AC input signal from the HVAC controls, unless what you did in the AEM settings was like a debugging ac relay test.
The other option is to use the ac signal from the HVAC controls to energize the ac relay directly. You will probably need a high sensitivity relay to push the ac relay if you do this. In other words, a relay to energize a relay.
I don't understand why your engine would idle up without an AC input signal from the HVAC controls, unless what you did in the AEM settings was like a debugging ac relay test.
The other option is to use the ac signal from the HVAC controls to energize the ac relay directly. You will probably need a high sensitivity relay to push the ac relay if you do this. In other words, a relay to energize a relay.
#4
1JZ Single SC400
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After doubke checking my findings it is indeed A17 and A27 for the ac compressor. The problem still arrives that after connecting to the AEM correctly, the compressor wouldnt kick on. I did indeed get the AC to kick on and off with the AC button on the climate control. I tried this method like ten times.
Worked perfect.
Now since this method is working, i acheived this by tying the two wires together on the harness side. Not involving the AEM at all.
Now i am curious to see if this method is correct or if maybe the settings in the AEM are off or has reverse polarity for signal. Might be set at positive output instead of negative signal. I want this done correctly. The idle is very low now and will not stay running without my foot on the gas. It dies all the time. Can someone tell me how to get into the settings for the AC compressor so i can double check everything ?
The bottom line is that I want it wired correctly and be able to use the AEM fir the rpm to rise when the AC is on or vice versa.
Worked perfect.
Now since this method is working, i acheived this by tying the two wires together on the harness side. Not involving the AEM at all.
Now i am curious to see if this method is correct or if maybe the settings in the AEM are off or has reverse polarity for signal. Might be set at positive output instead of negative signal. I want this done correctly. The idle is very low now and will not stay running without my foot on the gas. It dies all the time. Can someone tell me how to get into the settings for the AC compressor so i can double check everything ?
The bottom line is that I want it wired correctly and be able to use the AEM fir the rpm to rise when the AC is on or vice versa.
#5
1JZ Single SC400
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Figured out the AEM, on the settings. Redid the wiring as it should have been done originally and works great. Turns on and off with the LCD as normal, but the AEM increases the rpm under load, as it should. Thanks for the help...
The above info is correct on the pin locations on the AEM and the 1JZ harness.
The above info is correct on the pin locations on the AEM and the 1JZ harness.
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#10
1JZ Single SC400
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I will try and type exactly how to do it for you....
First unplug the battery, and then the 1jz harness from the AEM V2. If you are using the patch harness, due to having the Honda box from DM, then unplug it also. On the far right side of the photo above, you will see in the word, AC MG, this on the top row, fourth over from left. Remember how to read the plugs? lol... This is where you need to cut/splice/solder into the patch harness. This is one A17.
For the second one, find A27 which goes to the third row, second over which states AC. That is where to tie in this one.
In the AEM V2 settings go to home screen and at the top, click on Tools, then Configure Settings. Should bring up a list of the items wired in and you should see the AC compressor. Make sure it is checked. There is other settings in there for rpm raise, and so on. Play with these to see how your car will react.
I did this off of memory... I am sorry I couldn't take any pictures, due to all of my wiring is tied up by now. If for some reason the compressor doesnt come on, check the freon level. Make sure system is charged. Also makes sure it works with the button on the climate control also and the AUTO button as well. If it still doesnt work then reverse the wires or pin locations, put A17 where A27 is, and vice versa. Again I did this off of memory. I believe this correct tho. Pm me or post if something is different in the harness. GL
First unplug the battery, and then the 1jz harness from the AEM V2. If you are using the patch harness, due to having the Honda box from DM, then unplug it also. On the far right side of the photo above, you will see in the word, AC MG, this on the top row, fourth over from left. Remember how to read the plugs? lol... This is where you need to cut/splice/solder into the patch harness. This is one A17.
For the second one, find A27 which goes to the third row, second over which states AC. That is where to tie in this one.
In the AEM V2 settings go to home screen and at the top, click on Tools, then Configure Settings. Should bring up a list of the items wired in and you should see the AC compressor. Make sure it is checked. There is other settings in there for rpm raise, and so on. Play with these to see how your car will react.
I did this off of memory... I am sorry I couldn't take any pictures, due to all of my wiring is tied up by now. If for some reason the compressor doesnt come on, check the freon level. Make sure system is charged. Also makes sure it works with the button on the climate control also and the AUTO button as well. If it still doesnt work then reverse the wires or pin locations, put A17 where A27 is, and vice versa. Again I did this off of memory. I believe this correct tho. Pm me or post if something is different in the harness. GL
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1JZ Single SC400
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Oh I forgot to mention, the patch harness from DM didn't come with anything in the location on the third row where it says AC. I used an extra pin/wire that was supplied with the AEM. If you dont have any, then go buy one. GL
#13
1JZ Single SC400
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Glad I could out another member in the time of need. Finally I can contribute back to the SC community.
Thanks for the confidence on the Dyno, I will need it...
A little more precise instructions. This is for a Soarer harness with 1JZ harness. On the 1JZ harness going into the patch harness, unplug the far left one. This one says 32P on the top of the grey plug. You will find a white/black wire and a blue/red wire. Tap these two together and then tie in another seperate wire about five inches long. Take this seperate wire and plug it on the patch harness from the AEM. On the patch harness, its the fartherest left grey plug or the largest of the plugs or the same plug in that you unplugged originally. On the bottom row, third one over, it should have a vacant space. Plug the extra/seperate wire into this. Wolla, you have working AC. I needed to turn my settings on my AEM, CrZxDrtAgOn did not. If it doesnt work, try the listed above settings.
Thanks for the confidence on the Dyno, I will need it...
A little more precise instructions. This is for a Soarer harness with 1JZ harness. On the 1JZ harness going into the patch harness, unplug the far left one. This one says 32P on the top of the grey plug. You will find a white/black wire and a blue/red wire. Tap these two together and then tie in another seperate wire about five inches long. Take this seperate wire and plug it on the patch harness from the AEM. On the patch harness, its the fartherest left grey plug or the largest of the plugs or the same plug in that you unplugged originally. On the bottom row, third one over, it should have a vacant space. Plug the extra/seperate wire into this. Wolla, you have working AC. I needed to turn my settings on my AEM, CrZxDrtAgOn did not. If it doesnt work, try the listed above settings.
Last edited by 1JZPWRD; 06-24-12 at 08:40 AM.
#15
1JZ Single SC400
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The instructions are pretty straight forward. My car is at home. I wont have access to it till next week. I would try with the instructions first then if you need pictures post back up. You should be able to get it.