LT1 Wiring
02-15-2011, 10:01 PM
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Car: 84' Corvette, 96' Caprice
Engine: LT1, L99
Transmission: T-56, 4L60e
Axle/Gears: 3.07 POSI, 2.93 Open
LT1 Wiring
I got a custom LT1 harness. My problem is that the primary and secondary fans are "Negatively Triggered" according to the harness tag. So does that mean I have to wire up a relay like usual and run the PCM trigger to the ground on the relay? I'm kinda confused. haha I don't want to be frying wires....
02-16-2011, 12:06 AM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Re: LT1 Wiring
The relays are energized when the magnetic circuit is grounded, which is what the PCM does.
02-16-2011, 01:23 AM
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Car: 93 240SX
Engine: LQ9
Transmission: T56
Axle/Gears: 3.54 R200 IRS
Re: LT1 Wiring
Yes you need to wire up a relay, terminals 85&86 will be the ground triggers from the pcm, and an ignition hot wire, terminals 87&30 are battery power and output to the fan.
02-16-2011, 02:44 AM
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Car: 84' Corvette, 96' Caprice
Engine: LT1, L99
Transmission: T-56, 4L60e
Axle/Gears: 3.07 POSI, 2.93 Open
Re: LT1 Wiring
So I need to wire it up like this.... Won't that short out? Doesn't 86 have to have 12v+ to kick the relay?
02-16-2011, 08:14 AM
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Car: 92 Firebird
Engine: Supercharged 6.0
Transmission: T56
Axle/Gears: 8.8 3.73
Re: LT1 Wiring
Ok, back to the basics. A relay has a power in (30) power out (87) and two triggers (85,86). The triggers need to be 12v and ground, not both 12v or both ground. 85 and 86 can be switched to either 12v or ground without consequence bu most put 85 to ground and 86 to 12v
Now, build this
Its designed around factory relays which change over the years so pins arent given. For simplicity, ORN is 30, BLK/RED and BLK/PPL are 87, BRN 86 and Dk GRN/WHT 85
Now, build this
Its designed around factory relays which change over the years so pins arent given. For simplicity, ORN is 30, BLK/RED and BLK/PPL are 87, BRN 86 and Dk GRN/WHT 85
02-16-2011, 12:20 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
A relay is an electromagnetic switch. Power is switched by applying power to the magnetic (trigger, as Pocket called it) circuit.
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02-16-2011, 04:11 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Some relays have a schematic for the pins printed on the case. Between 85 & 86 will be a squiggly line - that represents the coils of the electromagnet.
If you Google "electromagnetic relay", Wikipedia has a decent explanation, including a pic of an automotive relay with the cover removed.
If you Google "electromagnetic relay", Wikipedia has a decent explanation, including a pic of an automotive relay with the cover removed.
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