any pointers on this guys? i have the fan switch wired up for the rate of air moving but what cable do i use for the hot/cold function? and what pattern does the vaccum lines have to be routed to be connected to the head unit. the head unit is a stock 97 t/a and what wire do i need to run to the compressor to get it to turn on? i have a wire comming off my harness i bought for a/c recognition and im sure it needs to be hooked up also.

 

TPI_TERROR Would be the one to talk to on this subject! I believe he used an LT1 cable for the heat door function, and IIRC there's a green wire that used to go from the 3rd gen hvac unit straight to the 3rd gen pressure cycling switch on the dryer, it goes through that switch and on to the high pressure switch and then goes straight to the compressor as a Dark Green. I believe the 3rd gen cycling switch and 3rd gen high pressure switch get deleted but i'm not 100% positive. That light green wire that goes from the hvac panel to the pressure cycling switch on the dryer needs to go straight to the computer to tell it that you've turned the a/c on.

 

Here's what I came up with to give you a better idea, I believe this is the same way TPI_TERROR did his:

 

So based of the diagram i've posted above here's a series of events that should happen.

1. You turn the switch on the hvac panel to a/c

2. When that happens, it will send a signal through the light green wire to the computer letting it know that you are requesting a/c (a/c signal request)

3. The computer will then ground the coil on the a/c relay, sending power through and to the a/c connector and it should start the compressor.

4. You'll see that there is a splice that goes from the relay to the compressor (dk green) and also runs back to the computer (dk green). The wire that goes back to the computer is to let the computer know that the compressor is running and has supply voltage.

5. You will also see the 4th gen High pressure a/c sensor on the diagram, you must have this sensor in order for everything to work. This sensor will screw into a port on the high pressure line that runs on the passenger side of the car after you remove the schrader valve.

Here is a good pinout i've been using for the 411 computer, i'm not sure if you're using the 411 computer but if you aren't, then the diagram i've posted above will most likely not be correct.

http://www.ls2.com/boggs/torques/2002pcm.htm

 

thanks dude

 

next question... what hvac vaccum lines go where?

 

Here:

https://www.thirdgen.org/forums/body...onversion.html

Look at the bottom of the first post, it shows which vacuum lines go where. Looks like this is good for a 97 as well.

 

This thread may also be of some help as well:

https://www.thirdgen.org/forums/body...ring-good.html

 

I'm in the process of changing to a 4th gen dash, I just used the 4th gen hvac box too. Saved alot of wiring ang vaccum issues even though the fab work to put it in was pure hell.

 

Were you able to get the lt1 heater cable to work? I bought one but it was also a tad to short, just like the ls1 cable.

 

I am using the calbe from a 93-94 dash. The heater controls are placed higher in the dash and require a longer cable which is actually a tad too long but I was able to route it so you cant see it and it works pretty good. You won't be able to get 100% control of the diverter door but if you are careful and plan ahead, you will be able to get it really close for hot and cold.

 

bookmarked. I've been looking for this info. thanks for posting it.
Kory

 

anybody have a vacuum diagram for using a trans am hvac head unit in these cars? ive searched and came up with nothing.. if i even had a picture of the trans am hvac lines that would help alot.