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....

 

The relays are energized when the magnetic circuit is grounded, which is what the PCM does.

 

What do you mean magnetic circuit? Sorry I'm not all there when it comes to specific terms.

 

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.

 

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?

 

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

 

A relay is an electromagnetic switch. Power is switched by applying power to the magnetic (trigger, as Pocket called it) circuit.

 

So this is how it should be wired then.

 

Thats right

five7kid, didnt know that was the proper name for it

 

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.