Just had my FAST fan control repaired. Prevent damage?

[V6UnderPressure]

I purchased a used FAST and the fan control wasn't working. I don't know if I damaged it or if it came like that. Now that it's repaired, how could I verify that I wont damage it again??? I have a manual fan control switch going to the relay, and that works. I have the fan control wire going to the original fan control wire that goes to the relay. All it is supposed to do is provide a ground. Any way that it could of been ME that damaged it???

Scott

 

[Otto J]

I purchased a used FAST and the fan control wasn't working. I don't know if I damaged it or if it came like that. Now that it's repaired, how could I verify that I wont damage it again??? I have a manual fan control switch going to the relay, and that works. I have the fan control wire going to the original fan control wire that goes to the relay. All it is supposed to do is provide a ground. Any way that it could of been ME that damaged it???

Scott

The fast unit carries a ground signal, that must be used with a relay,Do not send power back thru it as it may hurt the cicuitry.its a ground trigger

 

[V6UnderPressure]

So how would I wire this? I thought everything was built in? I thought all I had to do was send the fan control wire to the fan relay.

Scott

 

[Otto J]

The fast sends a ground signal out to a relay you must wire to your fan,You must make sure the wire that triggers your relay is the ground wire.
On a 4 wire relay you ahve 4 posts(dont use the center pin if it has 5)This is on a standard relay not the gm style, one pin gos to the bat,the opposit to the fan +,Then one goes to key on power the opposite wire to the fast fan triger wire. The only other wire id hte actual fan ground which goes to the chassis

 

[V6UnderPressure]

Ok, well all the oriiginal relays are there. Based on the diagram, I was under the impression that the fan wire (dark Green) coming from the original ecm harness is what I needed to tap into and that was it. Because when I put a ground to that wire, my fan comes on as expected. I thought that the fan control wire switched to ground (ie created a ground) when it was time to turn the fan on. Am I right or wrong here?

Scott

 

[Otto J]

your right,the green wire is hte wire to tap into,when you ground it it will turn the fan on,But you have to pull the resistor off the fan if you want high speed,The F.a.s.t jumpers usually trigger the low speed relay

 

[V6UnderPressure]

Ok, then all is correct. I just wanted to make sure. By the way I have the Ramchargers fan and racetronix harness. So as long as I have the fan control wire going to the low speed relay I am ok?