LT4 1996 radiator cooling fan relay how to test

[glefebv]

Hello all, I have a 1996 Vette LT-4, radiator cooling fans are not coming on. I have checked the fuse panel on the passenger side of the dash, I have also checked the maxi fuses in front on the battery. am now desirous of checking the cooling fan relays, how to do this? thanks in advance for any/all guidance

 

[ecss]

Hello all, I have a 1996 Vette LT-4, radiator cooling fans are not coming on. I have checked the fuse panel on the passenger side of the dash, I have also checked the maxi fuses in front on the battery. am now desirous of checking the cooling fan relays, how to do this? thanks in advance for any/all guidance

There are three relays involved.
You can identify the relays by the color of the wires at each relay socket.

Turn the ignition On.
At the relay socket.
Ground the Dark Green wire and both fans should run at low speed.
Ground both the Dark green wire and the Dark Blue wire and both fans should run at hi speed.