Alright for those that used the FULL 4thgen A/C system how did you wire it?
I got the 4thgen harness obviously and the 3rdgen wiring there too.
what splices to what? and do I need to add relays or is the 3rdgen relay that's already there, all I will need?

 

Im not sure how others used it... but I used the entire 4th gen A/C sytem. Every part. Im running the 4th gen fuse boxes. Not the entire body harness, just the fuse boxes and engine harness.

Im pretty sure the A/C compresser and all is controlled by the PCM. All I had to do was provide an A/C request signal to the PCM from the original 3rd gen harness. The wire I used is up by the HVAC wiring in the 3rd gen. I believe the wire gets 12 volts whenever the A/C compressor is supposed to run.

I just wired the 3rd gen wire up to the PCM's A/C request wire. Works 100% perfect.

If that was confusing let me know and I or someone else will elaborate...

J.

EDIT: EH...I just re-read what I posted last night. I was tired as crap and what I said is kinda confusing. Im going home tonight to work on the car, so Ill check the wiring out. The rest of what I said still stands. Most of the wiring was contained in my 4th gen harness, so I really only had to hook up one or two wires for it to work.

 

Yeah if you can tell me which wires you hooked up from the 3rdgen harness to the 4th gen.
I wonder since you used the 4thgen fuse box if there is a relay in that box you are using or if you are using the 3rdgen one.

 

I had an absolutly terrible day yesterday with the car. Check my thread to see why. I didnt even get to check the wire. For some rears, light green sticks out in my head as being the color of the wiring that I used from the 3rd gen wiring.

Thats really the ONLY thing I used from the 3rd gen. Everything else was contained in the 4th gen wiring/fuse blocks. The A/C stuff is in with the engine harness. Since the PCM controls most of it. Im pretty sure even if I wasnt using the 4th gen fuse blocks, it would have hooked up the same.

J.

 

In order to do it the factory way, you need to source a temp sensor and pressure sensor from a 4th gen. This way, the computer knows the temp and pressure so it can regulate the compressor cycling. The temp sensor is a small black box that has a probe next to the evaporator coil so it doesn't freeze up. The pressure sensor is a 3 wire, gray (5v), black (grnd) and red? (signal wire) that all go to the computer. This will require the use of a 4th gen pressure sensor to be adapted to the 3rd gen AC lines. I haven't gotten that far yet. I can snap some pics of the wires and connectors if you like.

 

Yeah all the A/C wiring is contained in the LS1 harness. I used the ENTIRE 4th gen system, lines and all. Which is what I thought he was asking about. In my case, the sensors were all there for me. I was much happier building the box with fiberglass to allow me to use the 4th gen evap, than messing with lines and all.

Its probably do-able though...I mean people do it all the time. But most people just use the LS1 compressor, and run it just like the thirdgen compressor. If you want the PCM to control it, you have to run it like it is in the 4th gen, and you'd then need all the sensors for it to work.

J.

 

Ghetto is right I am using the complete 4th gen a/c system. But I need to know which wires from the 3rdgen a/c to wire to the 4thgen part to trigger the compressor when I move the switch in the dash.
Also was curious about if it needed a relay added for the power drain.

Anyway if either one of you has pics or a writeup of your wiring on that I will add it to my ls1 swap guide that's linked off the FAQ here.

 

Thats the thing. You dont need to run anything from the 3rd gen to the compressor. You only need to give the PCM a signal... There is a wire in the 3rd gen HVAC wiring that gets 12 volts whenever the system needs the a/c compressor to run (based on the HVAC switch position). That wire gets attached to the PCM's "a/c request" pin. The rest of the wiring is taken care of in the LS1 harness.

Aaron are you using the 4th gen fuse blocks also? Or are you using the ls1 harness purely as standalone.

Ill be going home tonight to mess with the car, so Ill confirm which wire I hooked up, and see if there is any other info I can dig up for ya.

J.

 

For your question I am using the LS1 harness as a standalone. (Technically I am using it's boxes but rewired so no a/c relay or a/c wires going to it.)

The LS1 harness of course has the plug in the middle that goes in the hardline. Also the two plugs that go down the side of the engine to the compressor.
Now I could hook a wire to the A/C request wire on the LS1 harness, but I'm sure I need a relay somewhere in there so it doesn't burn up.

 

brought from the dead..


does the ls1 really have a temp sensor inside the hvac box.. or is that only lt1 hvac ?