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Re: 185 A/C issues on 205 swap

PostPosted: Thu Dec 30, 2010 11:38 am
by DeeCee
do you still have the st205 compressor? have you tried that instead of the 185 compressor?

Re: 185 A/C issues on 205 swap

PostPosted: Thu Dec 30, 2010 1:44 pm
by CMS-GT4
I did try it at first, but it got ruined since I did not seal it correctly when switching to the 185 head for the compressor.

Re: 185 A/C issues on 205 swap

PostPosted: Wed May 25, 2011 2:22 pm
by CMS-GT4
Bump, going to get moving on this again. Any help is appreciated.

Re: 185 A/C issues on 205 swap

PostPosted: Thu May 26, 2011 6:02 pm
by CMS-GT4
I found this on the 6th gen forums. I will see if I can reverse apply it to us once I have time maybe next week.
http://www.6gc.net/forums/index.php?sho ... 9327&st=20

Re: 185 A/C issues on 205 swap

PostPosted: Fri May 27, 2011 9:15 pm
by DeeCee
how about a st202 compressor. according to the epc, the units are the same between the models :)

Re: 185 A/C issues on 205 swap

PostPosted: Fri May 27, 2011 9:17 pm
by CMS-GT4
Well the 185 compressor works, and it kicks on without the act wire plugged in. I would rather figure out the wiring to make it just kick on and work.

Re: 185 A/C issues on 205 swap

PostPosted: Thu Jun 02, 2011 2:16 am
by soarer.jzz30
i am in the middle of re-wiring my gen 3 and gen 2 harness to mate up and it got me wondering... could you infact use the USDM 185 ECU for the A/C??? I mean like a piggy back??? run some of the sensors you need to it.... and make it work??? any thoughts???

Re: 185 A/C issues on 205 swap

PostPosted: Thu Jun 02, 2011 2:34 am
by CMS-GT4
Maybe if I still had it, I think I sold it a long time ago. I am sure there has to be a way to change the wiring in the amplifier to make this work. The 20x guys do it when swapping in 185 bits.

Re: 185 A/C issues on 205 swap

PostPosted: Thu Jun 02, 2011 2:47 am
by aus jd 2703
I havnt got gas in my system to test it but I suspect the ecu needs to see either 12v or earth and the aircon needs the reverse hence why it's either one or the other. So what ya need to do is un plug the wire and see if the ecu pin has 0v or 12v and if the wire has 0v or 12v.well in
Hoping it's this simple

Re: 185 A/C issues on 205 swap

PostPosted: Thu Jun 02, 2011 7:39 pm
by soarer.jzz30
[quote="CMS-GT4"]The magnetic clutch will not engage on the compressor.

Everything in the AC system is 185 except the AC idle up valve.


• I was looking at the ECU wiring and the 205 ecu controls the AC idle up valve, and the 185 does not.
So what controls the 185 AC idle valve?

• The 185 ECU has a control for the magnet clutch, but the 205 ecu does not. In its place is a second A/C amplifier.

Okay. I have been over the ECU and A/C controls and pin outs on everything on the 185 harness...
the 185 has an external A/C amplifier and so does the 205. you are right about one thing, the 205 ecu does in fact control the idle up from the VSV. but the amplifier on the 185 actually recieves the idle up signal and goes straight into the pressure switch/sensor near the firewall (EB-2) connector -yellow and red wire, the other side goes to the IJ1 connector(big white one in the dash near the ECU plugs) and it is yellow and blue, that goes directly into the A/C amplifier. the black and white wire coming from the A/C clutch goes to the A/C clutch relay and splits off to the ECU pin 10(C) from the IG1 pin4 connector and also goes to the condensor fan relay (very near the clutch relay is where it splits) . Now, there are only two sending signals from the amplifier (light green-black into pin 21(C))and one from the clutch relay I already mentioned into pin 10(C). both seem to stay the same on the 205 ECU... So there is apparently a black and yellow wire coming off the amplifier that either goes to the tie in of power black and yellows from ECU pins (C) 12 and 13... Or ties into the ignitor wire IGF1 which is also black and yellow. I have to go out and check in minute.... :shrug: And I assume since it is the ONLY noted wire that actually recieves signal from the ECU.... it perhaps controls the clutch engagement.... So, the question is... how to make it work?? well.. I am still working on it... I am thinking the LG-B wires (from the amplifier) output is controlled by the VSV for idle up. I assume it is power 12v. So I am thinking if you route that LG-B wire to the VSV idle (23(D) R-Y) pin on the 205 ECU it will give it a siidle up signal no problem. even if it is a ground switched VSV you can use your own relay to make that happen. Upon further review... the B-Y wire from the amplifier should in fact go to the +B or +B1 pins 12 and 13 on the ecu. So that should not be disconnected in the first place because it's in the dash somewhere near the IG1 harness... okay... So to conclude... Do not connect pin 8 to anything on the 205 harness... connect the LG-B wire from the amplifier (21C) to the VSV switch input on th 205 ECU (D23) R-B to activate clutch... I dont know where to ATS wire connect yet. lol. umm dont connect it?? I will look at the routing tonight for further diagnosis.... :doh: have to go to town right now!!

Re: 185 A/C issues on 205 swap

PostPosted: Sat Jun 04, 2011 9:56 pm
by CMS-GT4
I am interested to see what you find. In my experience, when I unplugged the atc wire the idle up did function. I am using the 205 idle VSV. This atc wire seems to be the hang up somehow.

Re: 185 A/C issues on 205 swap

PostPosted: Mon Jun 06, 2011 6:07 am
by soarer.jzz30
I just got done looming it up. have a few more things to do on the check list until I can start it up and check. I realized I only have one page of the 205 ECU diagram... only the right side.. I need the left to figure it out completely. But any ways. I am going to use the signals from the 185 VSV and Pin the 185 amplifier signal to the idle up... But... you said that when you connect the ACT wire the idle up works, but not well?? hmmm... I wonder what changes are being made from the ECU... I wish celica tech had their 6G FSM section link fixed so I could take a look at the schematics from the A/C and other side of the ECU.. :bangshead: :cry:

Re: 185 A/C issues on 205 swap

PostPosted: Mon Jun 06, 2011 4:04 pm
by CMS-GT4
Here are the digital BGBs for the 205. http://gt4.mwp.id.au/
Also other useful files.

Re: 185 A/C issues on 205 swap

PostPosted: Wed Jun 08, 2011 4:38 pm
by soarer.jzz30
Okay, thanks. I printed the A/C schematics and am going to compare the two and their outputs/inputs tonight and see what I come up with. Shouldn't be too bad.

Re: 185 A/C issues on 205 swap

PostPosted: Wed Jun 08, 2011 8:44 pm
by soarer.jzz30
Some interesting comparisons. The 205 A/C system is certainly less complicated than the climate control of the 185. I have only one conclusion. Both ECU's require two inputs and one output from the system. One is the ACT (which is the same on both) on the 205 there is AC1 and ATS, yet on the 185 there is AC (pin 10 on the 22 pin connector, I will call it plug (C)) And the third I am not seeing off the diagrams.

It is pissing me off that the chiltons does not show the tie-in anywhere on the engine control diagrams, yet it shows it coming off the amplifier with power flowing to it via a Black and Yellow wire that goes into the IJ1 connector near the ECU. FML I found it.... it goes to the ACA pin on the 5S-FE!!

The output wire that is supposed to go to the 205 Amplifer (AC1) is the only signal wire from the ECU to the amplifier. you guys were right that the 5S-FE is closer to the 205 than ours, but it still does not have a idle up vsv. You could always throw a ground on there because that's what it is searching for (although I do not see a point because it won't be changing anything) SO.. just leave it not connected?


Next up is the ACT input wire... It stays the same, simple enough... :D

Last on the list is the input required to idle up, it is the AC1 connector. This one made me think for a while on what the hell it does... It seems to be the signal being sent to the amplifier telling it the clutch relay is active and the A/C is on. Here is where the biggest difference between the systems becomes relevant. The 185 system uses a direct signal branching off from the B-W power wire on the normally non-powered side straight to the 10(C) pin on the ECU, however... The 205 does not seem to use this method, instead it uses a signal from the amplifier to tell the ECU the clutch is in fact engaged (instead of just telling it when the relay is closed it actually reads the lock sensor to see if the clutch is actually engaged or not).

On that theory, here is the plan.... you should have a signal wire from the clutch relay plugged into 10(C) on the 185 ECU plug. If your smart and lazy like me, then you did not move your original (C) connector and just changed some stuff around. If that is the case.. Take out pin 10(C) and plug it into pin 8(C) (ATS) (A/C Transmission Signal?) then, take the L-B pin 10(C) out of the 205 harness plug (C) and plug it into the now empty pin 10(C) on the 185. :)

As for the Idle up? The only thing i could come up with is taking out pin 17 of the IJ1 connector (from original idle up vsv) and plug it into the normal pin 23?? or perhaps even tie the original wire off from the IJ1 connector to activate it, that way you still get the signal to the amplifier... ughhh. I will say you should try and use your original VSV idle up instead of the gen3.. maybe that's your problem???

I don't know what else to say about all this. I have to deal with it when mine goes in near the end of this month. so yeah I am trying to figure it out before then. oh yeah, one last thing. The only difference between the two pumps that I could find is the color of the wires.. and. that... possibly.. the 185 might have a RPM sensor and the 205 is a "lock sensor"?? I have no idea if this will help at all. I am still going through everything to figure out functions!! AGHHH what a head ache