PWM cooling fan(s) control using ECM

[Z06vette]

I'm not sure that is the case, but I dont know enough about the software to rule that out. On my old setup - 24x LS1, 411 ecm There was an ac wire from the ecm that connected to the compressor 12+ wire. The E38 harness (from same vendor) does not have that feed. I ran the trinary switch on both cars to one of the fan relays. I spliced the trinary with the ecm fan1 trigger wire that goes to the fan relay. On my LS1 setup, this would allow either the trinary signal, or the ecm (via temp) to trigger the fan. It worked well. I wired this car the same way. The E38 was from an LY6 2500, which had a clutch fan. My tuner can command the fans via the laptop and they both run nice & steady. The car is getting some paint touch up right now; I'll revisit this when I get the car back. Thanks for your input. Scott