LS3 wiring questions
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Teching In
Joined: Feb 2021
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LS3 wiring questions Hey everyone. I am working on a1959 Chevy truck and have an American Autowire Classic Update Kit and a GM LS3 connect and cruise engine. This is my first project so I naively wired the AAW kit first without considering the LS3 wiring harness. In doing this I wired up a fuel pump relay and a fan relay that I am running through a Dakota Digital 2800 control module and VA trinary switch. In looking at my LS3 wiring harness, it has a gray wire for a fuel pump (there is a built in relay in the fuse box). There is also a wire for the fan (there is a built in relay in the fuse box). My question is should I go ahead and disconnect the fuel pump relay I already installed and wired and connect the fuel pump to the LS3 fuse box? What about the fan? Should I re-do the wiring on that also or leave in place what I have. Unfortunately, there is no tech support that I could find for the connect and cruise engine/wiring.
Thank you.
Thank you.
TECH Fanatic
Joined: Sep 2008
Posts: 1,643
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No sense in running two relays for either fuel pump or fan.
The fuel when controlled by the ECM will start the fuel pump when the key is in "on" but if the ECM doesn't see crank rotation it shuts down the fuel pump.
Fan controlled by the ECM is nice because you can program on/off temps as you like.
You need 12 volts constant and 12 volts in start and run to the ECM. Two separate wires from the AAW kit.
Also you can't over "ground" an LS swap. Engine to battery directly. Engine to frame. I do two.
The fuel when controlled by the ECM will start the fuel pump when the key is in "on" but if the ECM doesn't see crank rotation it shuts down the fuel pump.
Fan controlled by the ECM is nice because you can program on/off temps as you like.
You need 12 volts constant and 12 volts in start and run to the ECM. Two separate wires from the AAW kit.
Also you can't over "ground" an LS swap. Engine to battery directly. Engine to frame. I do two.
