Viscous fan clutch not working?

[bcbender]

Good morning all, I've been working on this for a few days, read all the threads I could find, was just looking to see if anyone can provide more input before I call the dlr.

We were evacuated from Arthur Thursday, and on the way home pulling my 16k 5er my truck (04 HO in sig) got hot... I limped it home and have been testing the fan clutch, by using the method in the shop manual. No DTC codes set so here goes.
So far I am able to ground the #1 terminal and set the PO480 code, verified that there is 12v and 5v signals present, I have done the "ground terminal #1" and run truck @ 2500 rpm, I have used an optical tach to check fan speed, after 10 ~ 15 min of running there was no increase in fan speed, (it stayed at about 370rpm with the engine running at 2500) I only let the engine get to about 210 the. I cooled it back down with a box fan. Problem in my thinking is if the fan is bad and going slow, why no DTC for fan or fan speed? I do not have a scan tool the will read fan speed so unless I go to the dealer I don't know what the ECM is seeing. Any thoughts before I order a new clutch or should I go drop $100 at the dlr..

Thanks in advance

 

[bcbender]

Is there something else I should be checking? I just don't want to pony up $450 if it's not the culprit.

 

[Wayne M.]

It's tough without the DRB. I'm spoiled and have access to one. There's a function test to duty cycle the fan. There should be DTC's set. It's tricky but you may have pending and don't know it. How does it spin by hand when cold?

 

[bcbender]

It doesn't feel bad, ( less than 1/2 rotation )
It just won't engage...it runs about 300 rpm no matter what the engine, ambient, a/c temp is @2500 rpm (engine speed)

 

[Wayne M.]

Def not right. It's 93 here today, and after sitting at a light, I can hear light roar on takeoff. You may have to bite the bullet. I'd check everything very closely first.
One thing, I have a hard time believing the engine will get to 210 that quick. Fan or not. Cross your tees and dot your I's.

 

[Tuesdak]

Bad gauge or temp sender(s)? Verify temps with a IR gun. How hot was hot? 210 to me is normal. Nothing wrong with paying a dealer, or local Cummins, diesel hot rod shop etc. Check what the fan clutch costs before going in. Out of warranty they may cut you a deal on parts or let you bring your own.

 

[rscurtis]

Turn on the AC- that should get the fan going in several minutes.

 

[MMeier]

Does the A/C work, if that has issues as well, swap out he transducer and see what happens. Worth a shot at this point, how many miles do you have on the truck ?

 

[bcbender]

Yes,the a/c works, but does not elevate the fan speed, it'll blow cold when driving but hot if you idle for a period of time. Checked the function of temp sensors, tps, etc last night, all are in range. Truck has 136,000 on it, what transducer do you speak of? Right now I made an appt next week to have the recall (steering) checked and the dealer said they could look at the fan at the same time. Not sure what else to do right now, it's a mystery!

 

[MMeier]

My bet is on the fan clutch itself then, when one of mine went south it didn;t throw a code or anything either, just stopped working. Transducer is a multi function type of pressure switch found on the high side line behind the right fender liner, toward the front ( on my '03).

 

[AH64ID]

I thought the fan clutch set a soft code, i.e. code without a CEL. So it would be worth scanning.

 

[Wayne M.]

I thought the fan clutch set a soft code, i.e. code without a CEL. So it would be worth scanning.

That's what I meant when I said pending (codes).

 

[bcbender]

So did I..., Pulled codes, none set(soft) other than the one I did following the service manual check procedure, PO480, that was set when I grounded terminal #1