I hope this is the right forum section (as it concerns both electrical wiring and PCM tuning), so here it goes.
I am acquiring parts for the electrical fan swap/mod on my '02 Suburban. This is a stock 5.3 K1500 with the 'large' engine radiator (34" inches wide, AFAIR) and mechanical, shaft-mounted visco clutch fan.
I will be using a Nelson harness and 2005+ GMT800 dual fans. I'm not shy of the mechanical or electrical work on this mod (hell, I usually do a ton of modding/servicing on my own); I got two questions, tho.
(1) The 2002 version is different in most of the writepus on this topic in that the e-fan relay & wiring harness requires a control input from what is cryptically referred to as the "A/C clutch trigger wire". I need clarification: does it mean the trigger wire for the A/C _clutch power relay_ or the A/C clutch _12V power wire_ going to the A/C clutch itself? I know GM can be pretty stupid about wiring color coding consistency, so I believe -- assuming it's the 12V power wire for the A/C clutch -- this is the dark green wire from the A/C clutch relay to the A/C clutch, like in the diagram below, not the dark green/white wire which triggers the relay - correct?
I know the DK/GN wire from the A/C clutch relay probably lives in the stock harness that goes by the red positive battery pole box to the left of the engine block. Is this correct? I also read there are several likewise-colored wires in the same harness, so I'd need to test for full 12V with the A/C clutch commanded to engage. (Or perhaps I should access the underhood relay center and tap directly below the respective relay's base?)
(2) I know I need to tune the PCM to enable and set the function of pin #42. I will be using HP Tuners.
I just need to know and verify which settings are correct:
First and foremost: I need to enable the PCM pin #42 to control the fans.
System > Fans tab: Fan 1 and Fan 2 set to ON
System > Fans tab, under 'Hardware':
Fan type: 2 fans
Under 'Fan 1 (first stage)':
On ECT: 185F
Off ECT: 178F
Under 'Fan 2 (second stage)':
On ECT: 205F
Off ECT: 185F
System > A/C tab:
I believe I need a setting option which is called "Analog" instead of "Analog, Cycling" under 'A/C System Type'.
For other settings that can be required - I am not certain and I'd appreciate any help. I do not know the compressor on/off pressures, on/off speeds, minimum run times, etc. for fan stages 1 & 2. There's a suggestion I found it's best to copy as much of the settings (the non-conflicting ones) from a 2005+ PCM file.
I am acquiring parts for the electrical fan swap/mod on my '02 Suburban. This is a stock 5.3 K1500 with the 'large' engine radiator (34" inches wide, AFAIR) and mechanical, shaft-mounted visco clutch fan.
I will be using a Nelson harness and 2005+ GMT800 dual fans. I'm not shy of the mechanical or electrical work on this mod (hell, I usually do a ton of modding/servicing on my own); I got two questions, tho.
(1) The 2002 version is different in most of the writepus on this topic in that the e-fan relay & wiring harness requires a control input from what is cryptically referred to as the "A/C clutch trigger wire". I need clarification: does it mean the trigger wire for the A/C _clutch power relay_ or the A/C clutch _12V power wire_ going to the A/C clutch itself? I know GM can be pretty stupid about wiring color coding consistency, so I believe -- assuming it's the 12V power wire for the A/C clutch -- this is the dark green wire from the A/C clutch relay to the A/C clutch, like in the diagram below, not the dark green/white wire which triggers the relay - correct?
I know the DK/GN wire from the A/C clutch relay probably lives in the stock harness that goes by the red positive battery pole box to the left of the engine block. Is this correct? I also read there are several likewise-colored wires in the same harness, so I'd need to test for full 12V with the A/C clutch commanded to engage. (Or perhaps I should access the underhood relay center and tap directly below the respective relay's base?)
(2) I know I need to tune the PCM to enable and set the function of pin #42. I will be using HP Tuners.
I just need to know and verify which settings are correct:
First and foremost: I need to enable the PCM pin #42 to control the fans.
EDIT: I was wrong, Recirculation Output is assigned to pin #33 on C2 of the PCM and should not be modified (it forces recirculation of air vs. A/C pressure buildup).I think it's called 'Recirculation Output' and needs to be set to 'Fan 2' - I am not sure about it, tho.
System > Fans tab: Fan 1 and Fan 2 set to ON
System > Fans tab, under 'Hardware':
Fan type: 2 fans
Under 'Fan 1 (first stage)':
On ECT: 185F
Off ECT: 178F
Under 'Fan 2 (second stage)':
On ECT: 205F
Off ECT: 185F
System > A/C tab:
I believe I need a setting option which is called "Analog" instead of "Analog, Cycling" under 'A/C System Type'.
For other settings that can be required - I am not certain and I'd appreciate any help. I do not know the compressor on/off pressures, on/off speeds, minimum run times, etc. for fan stages 1 & 2. There's a suggestion I found it's best to copy as much of the settings (the non-conflicting ones) from a 2005+ PCM file.
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