Another Fan Clutch Thread? (2016 RAM 6.7L Cummins)

[jlrodusmc]

I researched hand and found some helpful info, but I still need advice on my 2015 6.7L Cummins.

Main Issue: The AC does not cool when the engine is turned on or idle.

It is cold at speed, but then it goes from the high 40s to about 70 degrees when I stop at a light or in city traffic.

Second, I noticed temps went up while towing, but not noticeably high, at 208 degrees.

I have no DTCs, and the AC mechanic could not find any further issues (they said it was just too hot of a summer).

Fan Resistance exists for the first quarter, then releases for the rest of the turn, and then resistance again.

When I shut the engine down, the fan keeps spinning, like a ceiling fan.

When I idle to 1500 RPMs, you can hear the fan engage and suck air, but it quickly returns to normal after a few seconds.

I haven't checked fan speeds; I will get to that when the tachometer arrives.

I am going with a bad fan clutch, but I wanted your thoughts before I replace something that isn't broken.

Would you agree that the fan clutch is going?

Or what else should I try?

Another question would be, if I replace the fan clutch, should I also replace the water pump for preventive maintenance?

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[jlrodusmc]

Last summer, I forgot to mention the new compressor, evaporator, and condenser.

The issue was there before and after the compressor failed.

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[AK Bob]

See the attached troubleshooting information for testing the viscous fan drive.

You can jumper battery positive to the fan clutch supply and use your MM3 to monitor the fan RPM.

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[J695]

My 2012 had fan clutch issues when I bought it in 2016; when driving, it was OK with AC on.

As soon as I stopped, it would get warm.

There was a TSB out, so I bought a new fan clutch and haven't had an issue since.

If it's time to do coolant change, I always do the water pump,tstat and serpentine belt, idler pulley and tensioner, everything all at once, but that's how I do it.

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[Jmiller8649]

I also had this issue, and I had to replace the fan clutch and the bearing to which the fan clutch mounts.

It ended up grenadeing and puncturing my radiator.

I researched hand and found some helpful info, but I still need advice on my 2015 6.7L Cummins.

Main Issue: The AC does not cool when the engine is turned on or idle.

It is cold at speed, but then it goes from the high 40s to about 70 degrees when I stop at a light or in city traffic.

Second, I noticed temps went up while towing, but not noticeably high, at 208 degrees.

I have no DTCs, and the AC mechanic could not find any further issues (they said it was just too hot of a summer).

Fan Resistance exists for the first quarter, then releases for the rest of the turn, and then resistance again.

When I shut the engine down, the fan keeps spinning, like a ceiling fan.

When I idle to 1500 RPMs, you can hear the fan engage and suck air, but it quickly returns to normal after a few seconds.

I haven't checked fan speeds; I will get to that when the tachometer arrives.

I am going with a bad fan clutch, but I wanted your thoughts before I replace something that isn't broken.

Would you agree that the fan clutch is going?

Or what else should I try?

Another question would be, if I replace the fan clutch, should I also replace the water pump for preventive maintenance?

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[J695]

I also had this issue, and I had to replace the fan clutch and the bearing to which the fan clutch mounts.

It ended up grenadeing and puncturing my radiator.

Ouch, that sucks I just replaced the fan hub assembly.

I will replace the bearing in the old one so I will have a spare for the future.

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[jlrodusmc]

Before I apply power to the wrong pin, can someone confirm what I think is Pin B?

The colors aren't that obvious to me.

BR/LB is the second pin, next to the first dark blue.

IMG_0699.jpg

IMG_0698.jpg

IMG_0700.jpg

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[AK Bob]

Before I apply power to the wrong pin, can someone confirm what I think is Pin B?

The colors aren't that obvious to me.

BR/LB is the second pin, next to the first dark blue.

IMG_0699.jpg

IMG_0698.jpg

IMG_0700.jpg

Correct!

See the attached connector view.

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[jlrodusmc]

OK, so the fan clutch works with the jumper.

I connect the jumper, and fan RPMs are fine.

I really don’t understand the parameters that make it engage.

Fan Fuse looks good.

With no jumper, fan RPM is below

ES 700 - fan 150 (200 at other times)
1500 - 157
2000 - 155

So it’s barely moving.

Seems to me that without the signal, it might be too weak to at least have some form of engagement.

I'm still thinking of the fan clutch.

Back to square one, fan clutch or signal from module?

After a bit more research I’ll just be taking it to the AC shop.

I probably just don’t know what to look for.




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