E-fan controlling on 02 Chevy truck

[aaronr]

I have my E-fans set-up to be controlled 100% by the PCM. The fans are working fine with the tempter set points. I can't get the fans to come on high when the the A/C high side pressure get above 200psi set point. I was told that the 02-03 pcm can not control those set-point even know these set-point are in that 02-03yr tune file. I was also told if I get a 04 PCM that it was wired internally able to work those set-points. Can anybody verify this info for me?
Thanks

[Lextech]

The 2002 trucks with the 512kb, 12200411 PCM use a switch type of A/C system that does not control the fans based on A/C pressure. The A/C type is 3 on the trucks. The 2002 F-Body uses a type 2 A/C system and a sensor. The A/C type cannot be changed with EFILive as far as I know. I have set my truck up with the type 2 system. I am running a 2002 O/S. I am sending you a PM. I "might" be able to help you get it sorted.

Jeff

[turbo_bu]

Lextech,

If you can help to sort this out, could you share what needs to be changed? I am doing a standalone in a 56 Chevy for my dad and would like to setup his electric fans the same way. The donor engine / harness that I am using is from a 1/2 ton truck. I did not realize that you could setup the fans to trigger off of pressure on a 512 kb PCM. I thought you had to use the 1 MB PCM from the 04 and newer trucks.

Thanks,

Darren

[Lextech]

Hey Darren,
I have done it to my 98 GMC running the 12200411 PCM. I need to check into the wiring for Aarons 2002 truck.

Jeff

[aaronr]

Darren,
2000-2003 trucks can turn the fans on and off of by the temperature set points on pin 42 and 33 but my issue is the fan pull good amount of CFM on low that they hardly come on high. Then the pressure on the high side of the a/c start to climb and a/c air starts getting warm on the realy hot days. I live in AZ so summers are quite warm 105* to 115*. This was the reason i was trying to get the pressure sensor in there to be able to get the fans to come on high when the pressure set points were met.

Aaron

[Aloicious]

I run my MarkViii fan in my '96 truck with an '02 12200411 512k LS1B PCM. I'm using a LS1 A/C pressure sensor to control the fan based off the A/C pressure reading. like Jeff mentioned, the switch type A/C system doesn't actually give live A/C pressure feedback to the PCM, they're just high side and low side on/off switches that control it...you shouldn't need to change PCMs at all, but you will need some kind of pressure sensor like the one Jeff and I run in the high side of your A/C system to get an actual pressure reading to the PCM...luckily the GMT400 trucks Jeff and I have already have a port that the sensor works perfectly in, so you might have the same.

I use the LS1 pressure sensor P/N 22664328, its a 3 wire sensor...seeing as how the 2002 silverado uses the same OS as the 2002 fbodies, you might not even need to change the OS or anything...

you *should* be able to install that sensor in the A/C high side, and run 3 wires to the PCM. the sensor cavity A should splice into the C1-60 wire (black, or possibly org/blk) for the low reference, the sensor cavity B should splice into the C1-45 wire (grey) for a 5v reference, and you should add a new wire from cavity C to the PCM at C2-14 (which shouldn't be occupied) for the sensor signal...

I'm thinking that with that you should be able to log the A/C pressure, and the fan settings should respond to you pressure settings in the tune....I'm not 100% sure about the tune though, because my tune is based off the Fbody, not the silverado tune...but with the same OS I don't think it'd be a problem as long as the PCM gets the A/C pressure feedback it would basically be just for the fan control, and logging.

Jeff, I have some schematics if you need them. I don't have the LS1 A/C schematic with me, but if you need it, I can get it to you after I get off work. just let me know.

[Lextech]

Aloicious, I don't think just adding the sensor will do the trick. The tune needs the A/C type parameter set to 2 for the sensor input to function (As far as I know). There is also a type 1 that is on the 03-07 trucks but that is a 1mb PCM and might be a CAN signal based deal---Although I am not sure on that part.
Justin (Aloicious) has had a pressure controlled fan setup on his truck for a long time now--So, I definitely didn't originate this. I have helped a few guys out, but they have been 96-2000 GMT400 truck owners who have upgraded the Black PCM to the 0411 PCM.

Jeff

[aaronr]

Can you guy clarify the C1 and C2 part? How do you know witch one is C1 or C2? (Lextech) wait for your e-mail to verify information above.
Thanks

[Lextech]

C1 is the Blue connector and C2 is the Red connector.

Jeff

[Aloicious]

Aloicious, I don't think just adding the sensor will do the trick. The tune needs the A/C type parameter set to 2 for the sensor input to function (As far as I know). There is also a type 1 that is on the 03-07 trucks but that is a 1mb PCM and might be a CAN signal based deal---Although I am not sure on that part.
Justin (Aloicious) has had a pressure controlled fan setup on his truck for a long time now--So, I definitely didn't originate this. I have helped a few guys out, but they have been 96-2000 GMT400 truck owners who have upgraded the Black PCM to the 0411 PCM.

Jeff

you may be right, but I thought someone over on PPE added the sensor to an Xvan tune (which is switch controlled), and it worked, at least for the fans....so I'm wondering if he can leave his current AC setup alone, and just add the sensor for the fans (assuming the sensor would be recognized, but I'm thinking it might be) instead of trying to change over the AC control to the Fbody style....

its a thought at least..

[Lextech]

you may be right, but I thought someone over on PPE added the sensor to an Xvan tune (which is switch controlled), and it worked, at least for the fans....so I'm wondering if he can leave his current AC setup alone, and just add the sensor for the fans (assuming the sensor would be recognized, but I'm thinking it might be) instead of trying to change over the AC control to the Fbody style....

its a thought at least..

Hhmmm, Maybe so. That would be easy enough to try out. Just install the sensor and see if it works.

Aaron, I am looking into your wiring right now.

Jeff

[Aloicious]

this is the thread I was thinking about, with Robby running the A/C sensor....thats why I'm thinking it might work because I know we're running fbody based tunes for our 24x setups, but he isn't, so that makes me think that even if the vehicle is setup for different A/C control, it may still recognize the pressure sensor input, at least for fan control and logging if nothing else....(at least on the same 12212156 OS, which a 2002 truck should be on)
http://www.pacificp.com/forum/viewtopic.php?t=11255&highlight=sensor

[Lextech]

Actually, Robby sent me his non COS3 tune and I changed that parameter for him. Then he converted it to COS3. At least, that is how I remember it---It has been a while. It would still be easy enough to check the other way.

Jeff

[Aloicious]

you changed the A/C parameter?

yeah, someone will probably just have to install one and see if it works...

[S10Wildside]

I did a lot of bench testing on this about a month ago...
- 12200411 PCM
- 24x signal generator
- 0-5V A/C pressure sensor
- 12V LEDs as indicators for fan 1, fan 2, and A/C relay control
- EFILive
- TunerCat OBDII

No matter what I did with calibration settings, I was unable to begin with a truck calibration, change the A/C system type, and have proper fan control. If I remember correctly, I was able to get fan 1 (low speed) to turn on, but I could never get fan 2 (high speed) to turn on.

Now I was able to do an F-Body segment swap into the truck calibration to get the fans to work properly.

As an additional trick, I was able to wire in an 80K ohm, 1/4 watt, resistor across A/C pressure sensor 5V ref (pin 45 BLUE PCM) and signal (pin 14, RED PCM). To fake out the A/C pressure signal requirement.

[Aloicious]

hmm...so you were able to get the A/C sensor to read a pressure at the PCM on a non-fbody based tune with the addition of the resistors?

[S10Wildside]

hmm...so you were able to get the A/C sensor to read a pressure at the PCM on a non-fbody based tune with the addition of the resistors?

That's not what I'm saying. I don't recall, using the resistor, if the A/C Pressure PID displayed a value when using the truck calibraiton (I don't see why it wouldn't).

[Aloicious]

oh, okay, so you were just faking the signal from a sensor with the resistor. gotcha...

[aaronr]

Wow you guys were reading my mind and I haven't even been keeping up with this tread. I was going to test my factory tune and I also did 02 F-body tune and segment swap all my 5.3 and trans setting into.

[aaronr]

I did a lot of bench testing on this about a month ago...
- 12200411 PCM
- 24x signal generator
- 0-5V A/C pressure sensor
- 12V LEDs as indicators for fan 1, fan 2, and A/C relay control
- EFILive
- TunerCat OBDII

No matter what I did with calibration settings, I was unable to begin with a truck calibration, change the A/C system type, and have proper fan control. If I remember correctly, I was able to get fan 1 (low speed) to turn on, but I could never get fan 2 (high speed) to turn on.

Now I was able to do an F-Body segment swap into the truck calibration to get the fans to work properly.

As an additional trick, I was able to wire in an 80K ohm, 1/4 watt, resistor across A/C pressure sensor 5V ref (pin 45 BLUE PCM) and signal (pin 14, RED PCM). To fake out the A/C pressure signal requirement.

S10Wildside,
Can you tell me what you segment from the f-body tune into the truck calibration to get the fans to work properly.
thanks for the help.

The truck calibration didn't work but it was reading the voltage on the sensor.

change the A/C system type, in Tunercat worked. "Thanks to Lextech"

[S10Wildside]

S10Wildside,
Can you tell me what you segment from the f-body tune into the truck calibration to get the fans to work properly.
thanks for the help.

System segment swap.

[aaronr]

System segment swap.
Can you please give me more detail on this. How do you do a system segment swap? Sorry i'm not sure on what you are talking about.
Thanks

[aaronr]

Never mind I found what you were talking about.
Thanks

[aaronr]

O.k. Here i did some testing today and here what i came up with.

The f-body system segment swap to the truck tune that S10Wildside suggested worked but there was few down issue. One of the issue is the trans temp gauge in the cluster didn't work and the indicator light that shows you what gear you are in doesn't work.

Where Lextech converted the a/c type with Tunner cat worked like a charm.

Thanks Lextech for all your help

[aaronr]

Only issue that see now is that the compressor is not cycling when the low side gets below the low sides set point.
http://i241.photobucket.com/albums/ff48/russell1978/IMG_20120509_190414.jpg

[aaronr]

Guys any ideas to get around this. Thanks

[Taz]

Answering in this thread ... rather than your other thread ...

Can you post a photo of where you mounted the A/C Pressure Sensor ...


Regards,
Taz

[aaronr]

Taz,
I used theses pins for the new a/c pressure sensor --
"A" goes to the Black wire of your existing switch
"B" goes to PCM connector C1-45> added new wire
"C" goes to PCM connector C2-14>added new wire
I mounted the sensor on the high side down by the passenger side by the frame.
http://i241.photobucket.com/albums/ff48/russell1978/IMG_20120513_181839.jpg
http://i241.photobucket.com/albums/ff48/russell1978/IMG_20120513_181829.jpg

[aaronr]

Bump see if anybody has some ideas.

[Taz]

Sorry for the delay ... having one of those "whatever can go wrong, does go wrong" days.

Did the A/C lines ice up when you were using the Camaro system segment - or just with the altered truck segment ?

The A/C pressure sensor is in a good spot (and the correct line) - pins B & C are wired correctly - need to double check the schematics for pin A - trucks and Camaros vary on that one if memory serves.

I won't get to looking at the schematics for at least a few days ....


Regards,
Taz

[aaronr]

Yes the lines still ice-up on the Camaro system segment swap. Well let me know what you come up with. Maybe pin A is the issue and that why the compressor isn't cycling.

[Taz]

I should have confirmed earlier ... you are using an A/C Pressure Sensor for a 2002 Camaro (ACDelco # 15-5742, or the equivalent) correct ?

The sensor is new, and in proper working order correct ?


Regards,
Taz

[aaronr]

Yes it's a new sensor from 02 camaro. I' not sure what part # is off hand. A pin sensor is tied to body ground not low reference. Low reference is what call a clean ground. I ran truck tune to work today the compressor cycle just need too. Funny part is I can see what sensor is doing but don't have any programming to do anything with it. Let me know what you come up with.

[Taz]

... A pin sensor is tied to body ground not low reference. Low reference is what call a clean ground ...

With Camaros, pin A of the A/C Pressure Sensor is connected to PCM C2 pin 57. With trucks, PCM C2 pin 57 is the IAT Low Reference. That's from a cursory look at the schematics ... more to it than just that probably.

Perhaps it is a setting in the tune itself ... post your tune when you get a chance.


Regards,
Taz

[aaronr]

I don't have a truck pin out. I was using express van pin out because that what i could get my hands on. I see the truck use C2-55 for low side switch signal and that how it cycles the compressor. The camero doesn't use these ports for anything. I not shore how the camaro gets it's info to cycle the compressor unless it's looking at the a/c pressure sensor and cycles that way. I really don't think it's in tune but here you go. If you can look at wire diagram again see if you see anything let me know.

[Taz]

... I don't have a truck pin out. I was using express van pin out because that what i could get my hands on ...

Difficult to sort this type of conversion issue out, without OEM quality manuals - for all of the vehicles / platforms involved. Well worth the cost in the long run.



... not sure how the camaro gets it's info to cycle the compressor unless it's looking at the a/c pressure sensor and cycles that way...

That's exactly how the Camaro A/C system works - A/C Pressure Sensor input.


I was just taking a little break ... back to work ...


Regards,
Taz

[aaronr]

Well let me know if you see anything that might help me out. I just order some OEM manuals. To see if I can figure this out. Did you see anything that stuck out to you in the tune?

[Taz]

OK ... took a look through the schematics to confirm a few things.

The A/C Pressure Sensor operates on a 5 volt current - generated by the PCM. It must ground through a PCM 5 volt ground / low reference circuit. With Camaros pin A of the A/C Pressure Sensor splices into the 5 volt ground circuit of the IAT sensor.

Your truck uses an integrated MAF / IAT sensor. It has a 5 pin connector - pins A & B are the IAT sensor, pins C to E are the MAF. The MAF operates on a 12 volt current (pin D) and simply grounds to the chassis (pin C). The IAT operates on a 5 volt current, and grounds back (pin A) through the PCM.

On your MAF / IAT connector plug there is a black wire on one end (pin A) and a yellow wire on the other end (pin E).

I would suggest splicing pin A of your A/C Pressure Sensor to pin A of the MAF / IAT plug (the same way as a Camaro was wired).


Regards,
Taz

[aaronr]

Well here is what happen. I fixed the wire like Taz suggest in the post above but the compressor still ins't cycling. The a/c pressure sensor is talking to the fans fine but the a/c pressure isn't taking to the the compressor for some reason. I guess this why nobody has done it. Taz did see anything in the tune?

[aaronr]

Taz,
Do you see any issue with splicing C2-18 into Dk GRN a/c compressor clutch wire? I just don't under witch pin the a/c sensor pressure sensor need to talk to get a/c cycle. All 02 pcm are the same beside the programming inside correct?

Yes i'm i bought real manuals from alldata website. still leaning how to read these and get around on there web site.

Thanks for the help.

[Taz]

Sorry ... I had made certain assumptions about what you and the other gentlemen had discussed off the Forum, when you were setting up the tune using TunerCat.

Yes, just like the A/C Pressure Sensor, the A/C Compressor Clutch must be wired the same as a Camaro. If you have AllData now, pull up a schematic of a 2002 Camaro - then look at the A/C Compressor Controls for an LS1.

Both your truck and a Camaro use PCM C2 pin 43 to activate the A/C Compressor Clutch Relay. The Camaro set up monitors voltage to the A/C Compressor Clutch - your truck does not.

So Yes, splice pin A of the Compressor Clutch (DK GRN wire) - and connect it to PCM C2 pin 18.

Also, the High & Low switches your truck came with should be bypassed - the Camaro uses only the input from the A/C Pressure sensor.


Regards,
Taz

[aaronr]

After spending hours of looking at wire diagrams and modifying my wire harness. I can not get the truck a/c compressor to cycle with 02 camaro tune. I can tell you the fans work great with the a/c pressure sensor but the a/c compressor won't look at no matter what i do. The only way I see to get what i want out of this system is to add relay to switch the clutch signal on and off with low side pressure switch to keep from icing the a/c system up. What do you guys think.

Here is the wire diagram method think to do.
http://i241.photobucket.com/albums/ff48/russell1978/NEWRELAY-1.gif

The truck wire diagram
http://i241.photobucket.com/albums/ff48/russell1978/02CHEVYTRUCKDIAGRAM.gif

[Taz]

Something is not right ... could you post a log - with the first 5 or 10 seconds prior to activating the A/C - continuously logging to when the lines start to ice up.

It's been awhile ... think the A/C Pressure Sensor voltage PID is GM.ACP. Also log RPM, ECT, IAT, E-Fan status - and whatever else you think is relevant. The fewer PIDs the better - faster sampling, and easier for the brain to digest on playback.


EDIT: Also log A/C status, can't recall if there are any other A/C PIDs for the LS1-B PCM.

Regards,
Taz

[aaronr]

The A/C status "gm-accr" isn't supported on this pcm.

[Taz]

OK ... just trying to point you in the right direction ... connect to your PCM ... validate PIDs ... and select whatever A/C related PIDs you can ... as well as the other PIDs mentioned in post #43.


Regards,
Taz

[aaronr]

Taz,
I'm trying to get a/c system run off the 02 camaro tune so i can control the fan by the pressure sensor.

This file the compressors never cycles at all and the vent temp was at 20*
(2 truck with 02 Camaro system segment swap_0007.tun) goes with (truck tune with camaro system swap.efi)

When you look at this log file you will see that compressor is cycling with the truck tune. This tune will keep the vent temp at 40*
(current_0003.tun) goes with ( truck tune running ac sytem.efi)

any ideas??

[Taz]

Thanks for the logs ... they were helpful. Too bad GM.ACCR (Air Conditioning Status) is not a valid LS1-B PID (it is for Gen IV controllers) - it would tell us a great deal about what is happening with the A/C Compressor.

From the logs (especially the truck tune log) it seems that the A/C Compressor often disengages below 600 RPM - and when this happens, the A/C pressure drops off drastically.

Attached is PDF example of this, and a tune to try out - the idle values were increased to 650 RPM, and some other minor changes to the E-Fans.


Regards,
Taz

[aaronr]

Taz,
I think we are not on the same page here. I want the truck to run of the camaro tune that the only way I can have full control over the fans. Camaro tune is what ice system not the truck tune. If look at the camaro log and you will see the compressor wont cycle after high side gets below 150psl. That's why I want to put in the relay in. Thanks for info

[Taz]

I simply provided you with feedback on what I inferred from the logs you posted - a potential idle RPM issue - which may be a function an A/C table that is not accessible - who knows.

I posted some tuning suggestions in the truck tune posted. If you prefer to use the Camaro segment tune - just copy over the changes.

Not about being on the same page - it is up to you to get the A/C working the way you want - merely providing input / suggestions as you have been stuck a time or two on what to try next.


Regards,
Taz

[aaronr]

Thank you for your help and input.

[turbo_bu]

Not sure if this matters or not, but has the A/C Clutch Status (also seen it called Clutch Supplied Voltage) wire been added to the PCM yet? This is about the only "other" input that the PCM might need. Maybe the PCM doesn't know that the clutch has already been engaged?

A/C Clutch Status = C2(red) 18

This is wired into the power wire coming from the relay to the A/C clutch itself (+12V).

Aaron, thanks for all your hard work on this ... I am hoping you can get this worked out. I appreciate all the documenting you have done in this thread for the rest of us who are in the midst of LS1B swaps.

[aaronr]

Yeah I added the wire but it didn't do anything. I think will add the relay and be done with it.

[aaronr]

Yeah I added the wire but it didn't do anything. I think will add the relay and be done with it. For what ever reason the pressure sensor is not talking to the compressor.