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There are several ways to do it .I bypassed the porsche dme and am using the gm pcm to control a/c -wanted idle kick up -wot a/c compressor off and fan control by engine temp and speed .Others have used the dme to control. with apparently good results and a lot easier .Not familiar with the term excite wire .The dme grounds the a/c relay which provides 12 volts to engage the ac compressor clutch .The climate control communicates with the dme via a pwm signal . .
Green/Yellow from X59/1 plug direct to the excite pin on the LS1 compressor and ground the second pin.
Porsche a/c wire may not provide voltage if pcm doesn’t recognize a running engine? Also, system has to be filled with gas to turn on.
Originally Posted by dcdrechsel
There are several ways to do it .I bypassed the porsche dme and am using the gm pcm to control a/c -wanted idle kick up -wot a/c compressor off and fan control by engine temp and speed .Others have used the dme to control. with apparently good results and a lot easier .Not familiar with the term excite wire .The dme grounds the a/c relay which provides 12 volts to engage the ac compressor clutch .The climate control communicates with the dme via a pwm signal . .
I've seen quite a few guys use adapter fittings and some have cut off the Porsche fittings to weld on new universal fittings. Has anyone made lines that are bolt-on to the OEM Porsche 996 connections? I used to design these fittings and could draw them up quickly if nobody has done this yet. It seems simple and much easier than cutting/welding.
They make fittings that u can slip into the flexible hose if u cut off the aluminum section. U just slip it in and clamp the metal rings down. I had to use a repair union in one of my lines. I could have converted it to a standard ac fitting. One of the rings broke so i used s hose clamp.
Wow. Just read this whole thread!
Very nice!
I' love seeing these swaps, brings my two worlds together., Camaro's and Carrera's
Did the LS swap in my 70 Camaro, worth every single penny and frustration. the swap is 8 years old now and has 23,000 reliable miles on it and has seen 19 states.
this is intriguing. I hope u keep and continue to hot rod. love me some outlaw.....
If you're still looking for fittings try Coldhose in Ocala, FL Great company and just helped me with my 996 LS swap. The DME is not grounding the A/C relay. Have you gotten yours done and is it working?
plumber 452-is the system charged and do you have the porsche small alternator wire connected ?I don't know the dme logic but do know the climate control must see engine running which is the alternator wire and the dme needs a signal from the low pressure a/c sensor/switch that there is 25 psi or so in the system .
Thanks for the response. Yes the system is charged and I have 12V at the A/C Relay. I have voltage on pin 86 at the relay, that is the voltage side of the coil, and no voltage when I go from Pin 86+ to Pin 85-, which is the ground from the DME. I don't recall a small alternator wire. I kept the Porsche Alternator wiring which i know is rather large. Would that small wire have been "Bundled" in that wire? And the Alternator is charging.
two wires on the alternator -the charge wire and a thin blue wire -it feeds the instrument cluster -abs -climate control for engine on signal .That is on a 1999 996 what year is yours ?.
That wire would have been part of the engine harness -on the big connectors x59/1 pin12
My car is an 01. I'll have to look back through my notes as to which pins I kept. I don't recall that small blue wire but that was about a year ago that I did that portion of the swap. My instrument panel lights up as well as my climate control head unit and it seems to be functioning properly.
Thanks !!!! I'll look into that today. that would definitely explain my problem if the Climate Control Unit doesn't know that the engine is running.
So, I just tore back into my harness and I did keep the blue wire. I connected it to the Alternator wire coming from the GM ECU. I did find the blue wire in the Porsche wiring diagram and it appears to me that it's feeding the cluster, as you mentioned. Since my voltage gauge is working and everything seems to light up and work on the cluster do you think the way I have it wired up is O.K.? I've attached the GM alternator wiring diagram. I'm not strong in a lot of areas but I'm defiantly the weakest when it comes to electrical
05-24-2022, 04:54 PM
A/C 996.1 wire GN/YE
