E39 LSx a/c thread

[nsogiba]

Bump. going to try giving that idea a whirl tonight.

[OKsweetrides]

Make sure that the 12V+ feed from your IHKA has enough amperage to trigger the relays as you request.

At least on the E36, my digital AC has an effective digital 12v+, so it will not trigger a conventional relay due to the current being so low. Look into a reed switch or a solid state relay that have a super small threshold current.

[nsogiba]

I'll have to check and see what kind of amperage I'm getting out of that 12V+ signal which is pulled up from the IHKA. I am using this method to extract 12V from an LED on the IHKA courtesy of James39 on here:

http://www.bimmerforums.com/forum/sh...5#post26390785

If I'm not getting enough amperage to trigger that relay, I could always use the outgoing 12V signal from the relay that powers the AC clutch and backfeed it to trigger the Aux fan relay. Wouldn't be the first time I used one relay to trigger another on this swap.

[James39]

You probably aren't going to want the efan on all the time when the AC is on. It might pull the pressure down so low it shuts it off. And not sure you want the fan on at highway speeds.

[nsogiba]

Well, it worked out interestingly last night...I wired it all up and fired up the car after dark to test drive it, and yup, fan comes on with the snowflake. Flick on the headlights to take it around the block, and fan shuts off. Lights off, fan on. Lights on, fan off. Staring at the LED, it looks to get slightly dimmer when the backlighting goes on, so I guess the current was dropping just enough to not allow the pirated 12V signal to trigger that relay. So, the plan is to use the signal going to the AC clutch, which is post-relay. That'll also only run the fan when the clutch comes on...

[nsogiba]

Make sure that the 12V+ feed from your IHKA has enough amperage to trigger the relays as you request.

At least on the E36, my digital AC has an effective digital 12v+, so it will not trigger a conventional relay due to the current being so low. Look into a reed switch or a solid state relay that have a super small threshold current.

Fairly certain that this is what's causing my issue. AC compressor and aux fan will function fine with headlights off, but when i turn them on and backlighting on the IHKA goes on, the current drops enough to turn off the trigger to the relay. At least it was repeatable enough to figure out my issue, and the DMM confirmed the current drop with lights on...

now, where to find a solid state 12V relay on short notice? doesn't seem like radioshack carries any. I saw a Hella unit on summit racing... edit, nvm expected ship date is 6 months away LOL


I wonder if adding another reed relay after the 12V, .5A signal has left the IHKA will bring up the current enough to drive the PCM and switching relay with the headlights on...anyone have input?

[OKsweetrides]

nsogiba,

I responded to your PM.

Unfortunately, I'm not back in town until the 29th, and I have my physical schematic back at home which is my complete schematic. I have some fritz sketches I had made to give a ball park.


but this is the relay I have:
G2R-1A-T-DC12 R
aka: 9SIA5D52JC2815


EDIT:

On my AC... I have a 98 M3 which has a digital climate control system. There is a pin (my pin 11 on the 98 M3 digital clim cont mod) that ohms at something comical like 30mA. I metered out each pin originally to see what happens when I snow flake it. I have the pin 11 activate the relay with it's accompanying relay post to a ground, when actlivated, the circuit caused by pin 11 joins a fused 10A circuit to the pressure switch power supply. Most cars will turn the aux fan on when the AC is on, so you should have no issue with using that pressure switch power feed also triggering a dedicated aux fan relay. If you were to add another relay to the mix, you could have it to where the aux fan could be turned on by the driver OR the AC without backfeeding.

[aaronkuschel]

Well I meant physical fitment of the compressor as far as pulley depth (ie. can I use a truck compressor on a car bracket). After some research it looks like I need the LS1 F-Body compressor with corresponding bracket, or LS2 GTO stuff will work too.

I am running the Express van PCM, over to LT1swap website:

BLUE connector
Pin 45 GRY 2700 5 Volt Reference (A/C) -??

GREEN connector
14 RED/BLK 380 A/C Refrigerant Pressure Sensor Signal (A/C) - assume this is the input that gets 12V+ to say it's ok to turn on the compressor
43 DK GRN/WHT 459 A/C Compressor Clutch Relay Control (A/C) - assume this is the output that turns on the AC compressor. Wired straight to the compressor?
80 BLK 2751 Low Reference (A/C) - ??

Are the two "??" pins even necessary?

I am curious as to what the pigtail on the compressor looks like. What other wires does it need beside the output to turn on from the PCM.

thread resurrection! So....I have a express van pcm (6106 pcm) and I am running an independent electronic fan controller so my fan isn’t wired through the pcm. Can you or ANYONE please help me find a diagram or wiring concept to make my ac wired up and ready to go? I have the GM Pressure switch plumbed/wired and all hoses made. Rao wired this car’s ac up a couple years ago but I don’t know how he set this up. I’ve got Timmay’s old twin turbo 5.3 swap.

[Lantz]

Does anyone have a source for the #8 and 10 inside fit adapters. I looked pretty hard and couldn't find them unless i'm using the wrong name.

[Lantz]

Just in case someone is using this as a reference in the future. I finally found some after a lot of searching. Nosalgicac.com and Eaton EZ-Clip both have them. After I get further along I'll post my setup to run off Holley and a Sanden.

https://nostalgicac.com/fittings-hos...nside-fit.html
https://www.new-line.com/fittings/re...esaver-fitting