Electronic Fan Clutch Information

[L31MaxExpress]

What settings control the PWM output?
And are you using EV Fan setting?

I run a P59 with the EV Fan setting and have access to all the PWM controls using Universal Patcher.

I wired it the same as a 2003 5.3L Trailblazer.

When I first wired it up it was a simple On/Off on Fan 2 and I had a 3,000 cfm 16" puller in front of the clutch fan on the rear of the radiator on Fan 1. I set it up that way so the engaging the clutch was a last resort.

 

[L31MaxExpress]

This was when the van still had the 350, 16" puller and a thermal clutch. I had to move the electric fan about 6" to the driverside to clear EV connection. Radiator is also not sitting in its mounts in this picture, it had 2-3" of space when everything is mounted in its correct home with the radiator and shroud in place. I have tried several different setups to make this cool well and minimize power loss.

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[RDF1]

I run a P59 with the EV Fan setting and have access to all the PWM controls using Universal Patcher.

I wired it the same as a 2003 5.3L Trailblazer.

When I first wired it up it was a simple On/Off on Fan 2 and I had a 3,000 cfm 16" puller in front of the clutch fan on the rear of the radiator on Fan 1. I set it up that way so the engaging the clutch was a last resort.

AH!

I've been using dorman 902-310 solid state relays to PWM the 34" fans off the gmt800/gmt900 trucks but I'm using holley ECUs. PWM based off coolant Temps and AC high pressure signal

 

[L31MaxExpress]

AH!

I've been using dorman 902-310 solid state relays to PWM the 34" fans off the gmt800/gmt900 trucks but I'm using holley ECUs. PWM based off coolant Temps and AC high pressure signal

PWM on the EV Fan is a bit weird to control without the OE GM code doing it. It takes into account the belt pulley ratio and has a rpm feedback signal to the PCM.

 

[Scottm]

Is there a year on the trailblazer clutch that still has the 4 bolt water pump mount?

And what is that big plastic fan?

 

[L31MaxExpress]

Is there a year on the trailblazer clutch that still has the 4 bolt water pump mount?

And what is that big plastic fan?

Early Duramax fan blade with 3/4" trimmed off the blades.

All the Trailblazers have a threaded clutch.

 

[Scottm]

How did you adapt the clutch to your pump?

 

[L31MaxExpress]

My clutch had the same thread on the 97 van as well as the 8.1L in my 99 Tahoe.