Pete 587 fan not engaging...

hey all, i'm a diesel mechanic working on a Peterbilt 587 with the Paccar engine, it came in with the fan not engaging. i've checked fuses/relays, i've tried unhooking the fan clutch actuator, nothing makes it come on. i did notice, i have power on the yellow wire, but not the brown wire. the switch is normally closed, so i'm thinking i need power on that other side to open it. is there a fuse/relay somewhere that i'm missing? i don't have a computer to hook up to it to see what the ECM is asking for, just figured i'd post here and see what y'all had to say...

thanks a lot
Josh

 

yea, in my experience, most of them turn on when you remove power, so that's what i tried first (actually typed my steps in the wrong order above) and it didn't engage. but from what i see, the truck doesn't appear to be asking for it to come on...although i'm not sure what signal it's suppose to be sending...

 

update, i found a blown fuse i overlooked prior, the fan solenoid worked for about 5-10 seconds and stopped, but the fuse wasn't blown...that would be a relay disengaging it somewhere, right? which relay would control the fan? it's not clearly marked...