How to make AC work with your swap, aka: Need help with AC wiring thread Options

[lagos]

I'm also curious as to why there was any rewiring of the A/C system?

For my swap, I left all my A/C wiring stock (along with keeping the stock compressor). At that point, all you need to wire up are the couple wires that go to/from the ECU related to A/C idle up and A/C cut...

Without even hooking those wires up, I get A/C - just no idle up (I only use it on the freeway at the moment) and no A/C cut (turn it off before full throttle).

I looked into swapping over to all ST205 stuff, but putting together that mish-mash of parts and wiring looked like it was going to be hell.

-Charlie

do you have an st205 swap? if you do, then all your AC stuff probably just plugs in without having to rewire anything.

for the st185, you have to rewire a few things. its about 5-6 wires total that you need to rewire to make it work. its pretty easy.

[phattyduck]

do you have an st205 swap? if you do, then all your AC stuff probably just plugs in without having to rewire anything.

for the st185, you have to rewire a few things. its about 5-6 wires total that you need to rewire to make it work. its pretty easy.

Yup, ST205 - but into a '90 Camry... So no, nothing plugs in between the two A/C systems.

My clip had auto A/C and RHD, so some of the stuff probably would have been different anyway.

I left everything A/C related except the two wires to the ECU original. My only issue is that the ST205 ECU has 3 wires to the A/C system, and none of the pin names match up...

Either way though - it sounds like you have a decent plan of attack for your A/C system.

-Charlie

[lagos]

so i put everything back togther today to test out the ac but it dosnt seem to be working!?!

i start the car, turn the AC on, but i dont hear the radiator fans spin up or anything?

i checked for continuity from the black/white plug on the ac compressor to EA1 pin 10 and it IS there. then i checked for continuity from EA1 (male) pin 10 to the AC Rlay pin 3, and it is aslo there. so i dont understand why the AC and/or fans are not kicking on.

i disconnected the AC lines during my swap so the lines were empty. i tired to refill it with a can of r134 just to see if i would get any ac. i filled it to about 35psi... but still nothing.

any ideas?

[lagos]

"Pressure Switch
The pressure switch is threaded into the liquid line. It
sends a signal to the A/C amplifier to inhibit compressor operation
whenever high side pressure is too high or too low. "


seems there is a factory "kill switch" if your AC lines are too low or over filled. mybe this is my issue?

[MaskedMan]

maybe. this is becuase the oil, is mixed in with the refridgerant. If there is low refridgerant, then the compressor will not operate. Cuase the system will not turn on to protect the compressor against seizing up.

[lagos]

yeah... i think this is whats going on.

i traced the power routing for the whole ac system. it goes right from the AC fuse, to that presure switch on the AC lines. then the power goes to the AC amp. the sensor also has 2 more lines that are tied into the Fan relays. if i unplug the sensor, the fans go into their fail safe operation and stay on all times.

also, when i press the AC button ON, the sensor gets power to the wire that it should. so i think everything is wired up right. i think the wiring is right, i just need to get it recharged. i can also jump the 2 wires in that sensor and see if my AC clutch kicks in, to test things out even more if i want, but i dont know how safe it is to engage the AC clutch without any gas in there....

[Dr_Tweak]

You could do it for a couple seconds okay, just don't leave it running.

[lagos]

You could do it for a couple seconds okay, just don't leave it running.

if i take the time to type out how i wired everything up, can you doubble check it for me ? i want to make sure i didnt miss anything, before i go pay a shop to recharge it.

[lagos]

plug IM1 (female) 6th gen plug that goes behind the glove box.

(pin) (where i wired it to) (what it does)

pin1 = ecu plug E8 A- pin 21 = ACT function in the ecu
pin2 = ecu plug E8A - pin 10 = AC1 funtion on the ecu
pin3 = doesn not exist on 98 harness
pin4 = st185 plug IH1 - pin 4 = this leads to the white/red wire on the AC
pin4 = st185 plug IH1 - pin 5 = this leands to the white/blue on the AC
pin 6 = II1 pin 3 = this is the tach signal from the ignitor


PLUG 2c from the ST185 harness

pin6 = EA1, fuse box plug- pin 10 = this comes from the black/white power line for the AC clutch that is on the AC compressor


i THINK thats it.

[Dr_Tweak]

Just off the top of my head, it does look like you have everything correct. Really the most important thing is the a/c clutch circut, if that works then your a/c will work. Then we just need to make sure your engine idles up when it comes on. What year is your ECU?

-

*edit* Oh yeah, and you can pick up one of those little cans at Wal-mart or Pep Boys or whereever and fill it yourself. It's really easy, the instructions are on the can and it'll save you like $100.

-Doc

This post has been edited by Dr_Tweak: Jul 21, 2006 - 10:33 AM

[lagos]

Just off the top of my head, it does look like you have everything correct. Really the most important thing is the a/c clutch circut, if that works then your a/c will work. Then we just need to make sure your engine idles up when it comes on. What year is your ECU?

-

*edit* Oh yeah, and you can pick up one of those little cans at Wal-mart or Pep Boys or whereever and fill it yourself. It's really easy, the instructions are on the can and it'll save you like $100.

-Doc

the ecu is a 1990.

i have a bottle of 134. problem is , that i the AC lines were disconnected and there is air in the system. so i need to take it to a shop so that they can put it on an electric vac pump to bleed everything out before i can refill

[Dr_Tweak]

You don't actually *have* to have it vacuumed. I would give it a shot before taking it in.

-Doc

[WannabeGT4]

You don't actually *have* to have it vacuumed if you don't mind replacing the seals and/or compressor in a year or two. I would give it a shot before taking it in.

-Doc

Fixed.

[lagos]

IT WORKS!


i got another bottle of R134 because the one i was using was a few years old, and the gauge on it didint really sit at 0. so the whole time i thought i was over inflating it, when in fact i still had a lot of room to go. once the sensor saw there was enought psi in the system, it kicked the fans on and the AC relay. so now the AC works!

only problem is, that its not really as cold as it should be. so im still going to take it in and have it purged anyway, and refill it again. at least i got to learn all about my AC system while doing it...hahaha

[Fastbird]

Lagos, with everything working, does your car idle up when the A/C is turned on??

[lagos]

Lagos, with everything working, does your car idle up when the A/C is turned on??

no.

i have to install the idle up valve that does that. i think its somwhere in my basement. then i have to see how to wire that up and run some vac lines to it. its not a big deal tho, because the car dosnt stall out or anything, just idles a little less then it should.

This post has been edited by lagos: Jul 21, 2006 - 5:10 PM

[lagos]

i did a little ghetto bleeding . fill the low side while venting the high side. it did the trick and now the AC blows ICE COLD ! its so great driving around in a turbo car will all the comforts of a daily driver.

does anyone know the exact PSI our system should be filled to? i did mine to about 35psi.

[Aaagogo]

so this will be the working wiring configuration

plug IM1 (female) 6th gen plug that goes behind the glove box.

(pin) (where i wired it to) (what it does)

pin1 = ecu plug E8 A- pin 21 = ACT function in the ecu
pin2 = ecu plug E8A - pin 10 = AC1 funtion on the ecu
pin3 = doesn not exist on 98 harness
pin4 = st185 plug IH1 - pin 4 = this leads to the white/red wire on the AC
pin4 = st185 plug IH1 - pin 5 = this leands to the white/blue on the AC
pin 6 = II1 pin 3 = this is the tach signal from the ignitor


PLUG 2c from the ST185 harness

pin6 = EA1, fuse box plug- pin 10 = this comes from the black/white power line for the AC clutch that is on the AC compressor


i THINK thats it.

[lagos]

yep thats how you wire it up.

you just need to look up the plug names so that you know what and where they are. all that stuff is in the toyota wiring diagram books.

[MaskedMan]

does anyone know the exact PSI our system should be filled to? i did mine to about 35psi.

The low side pressure should be 21-35psi, and the high side pressure should be 190-220psi.