The Nelson harness and LS1 fans (00' Camaro in my case) is a great setup, but I'm going to add a flex-a-lite #108 (pusher) to help things out.

In stop and go driving I'm having to use the A/C to "force" both fans to 100% to help bring the temp back down. My "normal" (constant motion) running temp is about 185 on the stock guage. In stop and go, or after running hard then stopping, it peaks at about the 210+ mark and the weather hasn't really been that hot yet. This is happening on 75-80* days, and NOT towing anything.

When the fans are running at just 50% (A/C not on), they just ain't bringing the temp down unless the truck is moving. Since my timing is biased for a 160* tstat, I don't like this. I'm not gonna wait until 98* temps this summer to let this be a problem. So hopefully an extra 800 cfm fan will help out.

Before the e-fans, but with the 160* tstat, the temp guage stayed at the 185 mark and never really moved.

Here's the configs I'm considering:

On Nelson harness, disconnect A/C exicter wire from A/C compressor wire and connect to PCM exciter wire. Control aux fan via relay energized by A/C compressor wire.

PCM on only: Both LS1 fans 100%
A/C on only: Aux fan on
PCM on + A/C on: Both LS1 fans 100% and aux fan on

-or-

Leave Nelson harness connections in place. Control aux fan via relay energized by PCM exciter wire.

PCM on only: Both LS1 fans 50% and aux fan on
A/C on only: LS1 fan 2 on 100%
PCM on + A/C on: Both LS1 fans 100% and aux fan on

-or-

Leave Nelson harness connections in place. Control aux fan via relay energized by PCM exciter wire AND control aux fan via relay energized by A/C compressor wire.

PCM on only: Both LS1 fans 50% and aux fan on
A/C on only: LS1 fan 2 on 100% and aux fan on
PCM on + A/C on: Both LS1 fans 100% and aux fan on

I'm leaning towards the last one. BTW, the fan being added only draws 6.5 amps.

Later I'll add some switch control in the cab, but wan't to avoid messing with a fan switch while driving around town. I'm already having to mess with the damn A/C switch

Another thing I'd like to do is change A/C activated fan control from compressor switch to the low pressure switch discussed in this excellent thread http://forum.ls1truck.com/index.php?showtopic=3582
Has anyone got this method to work?