Electric fan issue on 03 Suburban

I don't want to cross post, but miscellaneous doesn't seem to see a lot of traffic...

I'm having an odd efan issue.
I set up the ls1fans.com harness and everything appears to be working but the AC fan2 startup.

In Scanner, when I turn on fan 1, fan 1 comes on, same with Fan2.
When I hit my temp settings, both fans come on low.
When I lower my second stage limits and hot those, both fans on high.
When I hit my AC pressure limits, both fans on low and high for state2.

Everything good so far.

But when I am below my AC pressure limits and I turn on my AC, fan 2 doesn't come on.
I can deal with both fans on low and lowering my pressure setting to keep things working, but I would like it to work the way it is intended if for nothing more than my own piece of mind.

I would appreciate any ideas as to what I can test and check here.

Attachment 99839
Attachment 99840

Thanks in advance.

At the moment I have lowered the stage 1 "Enable AC Press" tot he point where both fans come on low when the AC is turned on and the pressure jumps. But this feels like a cop out. I think I am missing something in the tune as when the AC comes on I do not see the PCM requesting fan2. When I manually request it, it some on with no issues....

Are you sure the fans are wired into the blue ECU connector 42 and the green ECU connector 33 and Fan1 IS actually on the drivers side? Your ECT is at 189* during this log. That is below the ECT on temp for fans. Try evaluating the fans once you are at operating temp and fan settings. Try having the fan come on at 185* and off at 182* Fan1 and 195* ON 186* Off fan2 and then check the AC fan control working or not. Unless motor mods have been made set the temps back for best economy and emissions.

The ac fan2 should run for 210 seconds minimum before shutting off. I do not know AC pressures but on a 2006 Suburban file I have the AC Enable pressure Fan1 is 220psi yours is 280. The mph speed for fans to turn off is lowered to 35mph. Depending on where in the world you live, 45mph is what it was set at and at your 35 there may not be enough airflow for condenser and cause too much head pressure damaging the AC compressor. Time will tell.

If there are cats still on the truck (yours are still enabled so probably still on it), I never mess with the COT settings. I only turn off while calibrating the MAF and VE tables. Changing that can a negative effect on the lifespan of expensive converters. Hope it works for you. It runs so hot and by reducing the enrichment rate it may not cool off fast enough.
What mods have been done to this motor? The o2 sensor Bank1 and 2 have been changed?

Hondaeater, Thanks for the reply.

Lots of ideas here, Let me run through them and see whats what.

I have checked the ECU connector, I am in blue 42 and green 33. Also, when testing and requesting fan 1 and fan 2, I get the correct fans, so the connectors seem to be working correctly and FAN1 is drivers side, 2 is passenger when they are running.
The fans also come on properly at temp. When I pass the stage1 temp both fans come on low (This is what should happen as I understand it, and as the ls1fans testing docs claim as well). When I lower the stage 2 temp both fans come on high when that temp is hit..
I have tested this both by lowering the temp and by letting stage1 get hit from reaching the currently set temp.
The fan2 min run rime is set to 210 seconds already, but the fan never starts for the AC.

The pressure was set to 220 on the stage1 fan settings, I raised it to 280 so it would not go on due to pressure. its hard to see if fan2 is going on if both fans are on low because stage1 has been tripped.
I set that at 35 because I have a stock 2006 Silverado file example that shows 45 and a a fan upgrade file that shows 25, so I split the difference and have been watching the pressure to see if there are issues. Ill keep an eye on it, but thanks for the catch.

not sure where the COT settings come in, I haven't touched mine, they should be stock.
No mods to the motor at all. Just the tune, in a few places (Spark, O2 Rich/Lean and PE and some shift point changes), and the electric fans. The 02 sensors are the ones that were on it when I purchased it a few weeks ago. I don't see anything that looks like they need replacing at the moment, but I might be missing something..?

Overall, everything appears to be working except Fan 2 doesn't start when I turn on the AC. I was worried at first that I had wired something wrong. But the issue appears to be the ECU not requesting the fan come on. I figure it has to be a tune mistake I made, but I have done a few days worth of comparisons and testing at this point and the only thing I can think of is that I need to do a segment swap........

Any other thoughts?
I keep coming back to a segment swap, but everything I have read so far is that this should work with the proper settings.

Are there electric fan control differences between the same os on different vehicles?
I have 2 tunes from the repo for 2006 Siverados. They have the same OS though, and they show the same options that I already have. Is there a way to tell the differences between segments on different OSs?

Try setting the delay times to "0" seconds. I added an electric fan to a motor that originally had a mechanical fan and ran into several strange issues that I couldn't explain the causes but I did find the fix.

vantage255, FYI the Fuel>temp control>Catalyst Protection> Enrichment rate vs temp delta is what I was referring to. Your table is not like a stock 03 silverado or an 06 suburban. Just letting you know it ramps in very slow. The others start at 12=0.550 by 60= 1.06 yours is 12=0.030 and never gets above 0.700 FWIW. The Fuel>O2 Sensors>Rich lean vs airflow> B1 & B2 o2 had this little dip at 6 = 350 not stock and I would not adjust MAF or VE with that in there..

Reverse the ECU pins. You should have 3 relays, 2 4pin relays they are on/off and 1 5pin relay which is always passing pin 30 to 87a. When stage 1 temp is met it puts both fans in low speed because only one relay is used providing 1/2 power to 2 fans because fan 2 gets powered thru the 5pin pass thru relay. When second stage temp is hit both 4 pin relays are active giving max current. Because the stage 2 switch on pin 85 is ON it separates the series pass thru of the 5pin by energizing it's pin 85 creating 2 parellel circuits and HIGH ON both fans. The relay for 1 fan is always HIGH speed ok it is the function of the 5pin relay to turn on fan2 in series (low speed) until the trigger (AC or temp) of fan2 relay and separates the 2 fans into parallel High Speed. When AC clutch switch comes on, fan 2 relay pin 85 should be ON and HIGH speed regardless of other fan switch. Rambling I know but its late. The 5pin relay may just be wired to your fan1 connector or ECU Pin controls the "wrong" 4pin relay so try switching the green/blue ECU pins. I think this will do it but it should have both fans on LOW with AC clutch ON, temps not met if ECU pins were reversed (not by you but in the loom) and never have a single high speed fan mode. VCM Scanner channel to make sure ECU sees the AC Clutch comes on.

* You must have your PCM activated or tuned to take advantage of the trouble free OEM operations of the fans. By doing so the fans will operate in your truck exactly as they do in the Corvette, Camaro and Firebird. The fans will have the ability to operate in 2 fans high, 2 fans low and a single fans high depending on the demand read by the PCM.
Funny, like that trouble free part!

Hondaeater,
Thanks for the info, The CAT enrichment rate v temp tables isn't one I had ever changed. That's the way the suburban came to me. I guess it has been tweaked with before.
The Rich/Leave V Airflow is me. I know not to tune with it that way, but I am testing some stuff from the gas mileage sticky and it appears to be working, at least in a small way.

SteelGreenStallion, thanks as well for that idea.

I will get to work on this this evening and see where I get to.

Thank you for the help!