AC relay wiring

[turbobuick]

I want to use the AC clutch shut off control function in the Gen 7. The output from the Gen 7 is a ground. Looking at the factory wiring (last schematic)
http://www.installationinstructions.com/vin7/GN Electrical System Schematics.pdf

The factory ECM uses A2 as a 12v out put to the passenger side relay and uses B8 as a gnd input signal from the same relay.

Looking at the relay it has one pin on top with two blue wires which one goes to the AC compressor and the other to B8 so that is the gnd? The 3 on the bottom are brown/blk, green/yell, and dark blue. The schematic shows all the same except the switched 12v being pink/blk and in my harness it appears to be brown/blk.

My understanding is that the factory ECM applies a 12v signal to the relay which is normally open. Once it receives the 12v signal it closes and grounds the dark blue wire to the AC clutch which disengages it?

I am trying to avoid wiring in a separate relay, so how do I rewire this relay to work with a ground input as opposed to a 12v? This appears to be a simple 4 post relay. I have two grounds on one post going to the AC and to pin B8. I have a 12v input, 12v pwr and a gnd out to the AC. So if I swap the green/yellow with the light blue wire and disconnect the ground signal wire coming from the AC do you guys think this will work?

Hope I didn't lose anyone in this confusion. It'll be easier to understand if you look at the schematic I posted.
Thanks

 

[TurboBuRick]

The factory ecm is switching the ground. Hook green and yellow wire to the gen 7.

 

[turbobuick]

The factory ecm is switching the ground. Hook green and yellow wire to the gen 7.

Your right I have it backwards the Gen 7 will be 12v out then, it is the opposite. If that's the case I would need to switch green/yellow with the brown/blk wire?

 

[TurboBuRick]

Your right I have it backwards the Gen 7 will be 12v out then, it is the opposite. If that's the case I would need to switch green/yellow with the brown/blk wire?

Yes that should work. Put the green and yellow right to ground and switch the brown and black with the gen 7.

 

[norbs]

As far as i recall the gen 7 switches the ground, but in order for it to work it is opposite. The relay must be in the N.C. position with the a/c turned off in the car. The factory relay has no N.C pin so you can;t use it. You need to swap it to a n.c relay and just connect the way it was from the factory, but using the n.c contact instead of the N.O. contact.

Also ,word of note: the factory ecu will richen the a/f mixture and bump up the IAC .4 of a second before giving the output to the compressor relay to turn on. The gen 7 can only bump the IAC but will not richen the mixture, like the factory ecu does.

 

[turbobuick]

As far as i recall the gen 7 switches the ground, but in order for it to work it is opposite. The relay must be in the N.C. position with the a/c turned off in the car. The factory relay has no N.C pin so you can;t use it. You need to swap it to a n.c relay and just connect the way it was from the factory, but using the n.c contact instead of the N.O. contact.

Also ,word of note: the factory ecu will richen the a/f mixture and bump up the IAC .4 of a second before giving the output to the compressor relay to turn on. The gen 7 can only bump the IAC but will not richen the mixture, like the factory ecu does.

Thanks Norbs. It is my understanding the factory ECM will receive a 12v signal on pin B8 when the AC is activated which will close the relay on the passenger side fender. When the ECM wants to disengage the AC clutch it uses the A2 green/yellow wire to break the ground and open the relay which will disengage the AC clutch. Is this correct?

I believe you are right the Gen 7 is a ground out like I thought originally but the signal out will engage the ground when the factory ECM uses the A2 wire to disengage the ground?

So if I ground the relay using the green/yellow wire the AC will work? I think I am just going to wire a second relay under the dash that is closed to ground the factory relay and open it with the Gen 7 to break the ground when I want to disengage the AC clutch?

Let me know what you think.

 

[norbs]

IF you ground the a2 wire, yes the compressor will work all the time. Your 2nd relay inline under the dash being n.c. fed through the dfi will also work as you described, but if you could find a relay that would plug into the factory connector that has a n.c contact, you would just have to move one pin the in relay connector to the n.c contact and it would work with no other mods too.

 

[KevinB]

On the adding fuel part, could you use one of the nos controllers and switch it on when the ac is on?

 

[turbobuick]

On the adding fuel part, could you use one of the nos controllers and switch it on when the ac is on?

I can run my O2 correction at idle and the WBO2 on the Gen 7 will more than compensate as long as the tune is right.

Norbs that's the million dollar question. I will call John Spina Monday and see what he can come up with.

 

[KevinB]

I can run my O2 correction at idle and the WBO2 on the Gen 7 will more than compensate as long as the tune is right.

Norbs that's the million dollar question. I will call John Spina Monday and see what he can come up with.

Cool, I may call you with some questions later this week when I get my gen7 in this stocker here

 

[norbs]

I;ve tried the NOS input the adjustment is to coarse for this adjustment with big injectors. Also when the 2nd fan comes on it will need more fuel again. The wide band correction can handle this to a point you will have to test it out if it works for you, I did not have good luck with it with fueling based in park/gear a/c on and off and 2 cooling fans cycling in and out, my a.f was a mess, big swings all over the place. It just could have been my base map being out to lunch too. You may have to do alot of tweaking , i ran out of patience....

 

[KevinB]

What did you end up doing? I'm hooking my dfi up now. Looks like you can you send the ac signal to input 2 and use that to bump up the idle. Did you rewire the relay or add another?

Also, about the tcc hookup. Looks like you can set that in the settings for a ground or + signal??

 

[turbobuick]

What did you end up doing? I'm hooking my dfi up now. Looks like you can you send the ac signal to input 2 and use that to bump up the idle. Did you rewire the relay or add another?

Also, about the tcc hookup. Looks like you can set that in the settings for a ground or + signal??

Nothing yet moved on to other stuff that needed finished. I am going to run another relay to break the ground to the factory relay to disengage the AC system. You will have to ground the firewall relay to get the system to work.

I have the wiring and relay for the TCC give me a call.

 

[turbobuick]

Now that I have fixed the C68 and it is working again I am back to FINALLY wiring the AC for the GEN7 so I am resurrecting this thread. I realize if I just ground the Green/yellow wire coming from the factory AC cutout relay on the pass fender the AC will work. BUT I would like to use some of the tuning features in the GEN7 for AC control.

The GEN 7 has one input to signal AC is active and one output to disengage the AC clutch at WOT just like the factory does but it is wired completely different.

On the GEN 7
K3 pin is 12v input to signal AC is active
G2 pin is GND output to disengage AC clutch at certain TPS threshold to a relay that is normally open.

Stock GM ECU:

B8 pin is AC signal that AC is on and active. This is a GND signal input to the stock ECU from the relay? Not sure how this works in Factory setting. Once AC is turned on this is a GND signal input to ECM? I am going to need a 12v signal wire when AC is active any ideas?
http://www.gnttype.org/techarea/images/wiring_images/ac_heater_blowerswitch.jpg

The A2 pin is GND out from the ECM that opens a normally closed relay for AC clutch cut off. To make this work I need a relay that will GND the A2 wire with a relay that is normally open. Opposite of how the factory is wired.

Here is what I've come up with:
Basic 5 pole relay
85---coil---86
30 trigger
87 open pole
87a closed pole

Pole 86 G2 PIN GEN 7 this will be open until GEN 7 GND it at 75% TPS
Pole 87a to Factory A2 Yell/GRN wire as GND to factory AC cut out relay
Pole 87 to GND
Pole 30 GND
Pole 85 to factory 12v signal wire that is only active when AC is on. This wire will go to K3 PIN in GEN 7 too. I am currently looking for this wire in the factory harness so if you know of a good one to use please LMK.

So if my thinking is right (which it probably isnt) AC is turned on produces 12 signal to pole 85 on relay and GEN7 K3 pin.
87 & 30 are gnds
87a is normally closed grounding factory AC cutout relay so AC works when relay is active
86 is open till GEN7 gnds it and opens relay to shut off AC clutch at 75% TPS

LMK what you guys think, this is kind of confusing to figure out. I also need to find a wire to use as 12 signal wire when AC is turned on in the factory wiring, any ideas?

 

[turbobuick]

If I use the purple C2 pin C compressor output wire from the C68 it is 12 volts when the compressor is off and switches to 6 volts compressor on so that wont work as a 12v input for the GEN7. The brown white wire is 12v out when the Control module is turned on BUT if I use this wire the AC controls in the GEN7 will trigger with heat or AC when ever the unit is on.

Does anyone know if the C1 pin 3 TAN wire coming out of the control module to the vac solenoid module under the dash is 12 volts out or a ground out? It looks like it may be a ground out as it states in the diagnostic part to test it you back probe the pin and ground it to energize the solenoid. If so I can use it as a signal and run a another relay to power the GEN7.
http://www.installationinstructions.com/FYI/climatecontrol-schematics-87.pdf

If so would put the cutoff relay under the hood, splicing into the factory cutoff relay wiring, I wanted to avoid running two relays but I don't think it is possible to do so at this point.

 

[turbobuick]

I;ve tried e NOS input the adjustment is to coarse for this adjustment with big injectors. Also when the 2nd fan comes on it will need more fuel again. The wide band correction can handle this to a point you will have to test it out if it works for you, I did not have good luck with it with fueling based in park/gear a/c on and off and 2 cooling fans cycling in and out, my a.f was a mess, big swings all over the place. It just could have been my base map being out to lunch too. You may have to do alot of tweaking , i ran out of patience....

I finally got it all working and it works as well if not better than the factory. AC turns on kicks up idle Fueling is spot on, no stumbles runs as smooth as it did without AC on. I ended up only needing one relay for the WOT cut off. The other ECM wire is 12 volt so it can be connected directly to the K1 pin. I did spend a lot of time on the drive ability tables on this car more so than the race car. Its pretty cool all you can do with this ECU once you get into learning what it is capable of.

 

[norbs]

Glad to hear, but I would not go back to dfi, since I am spoiled with logging 24 items at 20 frames.sec, and I like real ve numbers not decimals. and I could not take the random ecu connection drop out problems for no apparent reasons.(could have been a windows thing) However if your happy with it, that's cool, you have been on this for a long time and you deserve success!

P.S * XFI has a feature if the coolant temp gets too high the ac compressor cuts out preventing the car from overheating, saved me a couple times in traffic from a melt down.

 

[turbobuick]

Hey Norbs, I wasnt looking to have a XFI Gen 7 debate as most of the reasons someone pics one over the other is mostly personal preference and obviously you like your FAST better which is great.

I never had the ECU "drop" out and as far as communication with the Gen 7 I never had an issue with that either using a computer with XP. The datalogger on the other hand is a mess and none of it works well with 64 but OS. I agree with you on the datalogging that is definitely one of Accels downfalls.

On my new race car I went with a Racepak to eliminate the datalogging issues and really that will eliminate 99% of the issues I've had with the Gen7. On the grey car I really dont need anything more than the laptop to log with. I actually looked at other systems to run on the new car and TBH outside of datalogging there are few that offer anything more than the Gen7 already offers. Funny thing is I initially ran a FAST on my TSO car and back in 03/04 and was running pretty well with it at 156 mph. Had the XFI been out at the time I probably would have one today but at the time about the only other choice was a classic FAST and there is really very little comparison between a Gen 7 and classic FAST.

As far as the fractionated VE table, with a three decimal fractionated value it actually has more precise resolution than a whole number. In my experience it is more accurate but it is also can be a little more sensitive in dialing in the correct VE values. This may be the reason you had so many issues with your car idling. I did have to adjust a lot of the transient fueling tables and especially the TAU table to get everything to work well and you have to have the VE table correct or REALLY close before you get into the other tables.

As far as turning the AC off in traffic why not turn the high speed fan relay on like the factory does?

LOL, I haven't been at this AC issue that long. The restoration on this car has been a long slow one that is finally coming to an end. This was a complete tear down and frame off resto I started in 05 and now just finishing up the little stuff this year. I had WAY more issues getting the rest of the car sorted out and the C68 climate control to work first before messing with the AC. The car ran a string of 11.00's last fall at BG with a VERY mild tune up and that is exactly how I run it around on the street today. T-tops out and AC blasting it has been a lot of fun to drive and I haven't had a TR I to drive around and enjoy like this since the 90's. BTW it is a Canadian T-type, eh!

 

[norbs]

Well, Chris I didn;t want to get into a big debate, just sharing my experiences that I encountered back then with the system. You have to understand I have a built in computer in the car and its on all the time while driving, the communication errors would only pop up once maybe a week or after a 2 hours drive, totally random. This thread is 2 years old when looking at the date when you started this project, just seemed like a big time gap upon completion that's all. Every system as issues, you probably clicked my wanted xfi improvement list, and you can see what I expect out of a system. Wish I had the funds and resources to build my own system. Good to see your enjoying the car!