Another One Bites The Dust - Fan Controller

[roaniecowpony]

Brother calls me yesterday, says the fan is not running on his jeep. Apparently, I am forever tied to this jeep.

I figure it's one of three things, Z-case fuse, Green CAN bus junction block, or the aftermarket fan controller. I load up a carbon pile tester as well as an electronic battery tester, multimeter, spare fan, Z-case fuse, CAN bus block, and the usual tools. Get to his house and it's just barely under 100F. No shade to work in. This is elderly abuse. Brother offers water. I decline, since wife packed up two thermos' with ice water and a couple plastic bottles for the drive. Peeing was more on my mind.

Brother suspects it's the aftermarket fan controller. He thinks we should remove it. I have no reason to argue. Since I've installed a few of these and removed one other, I'm elected for the labor. It didn't go quite as fast in 100F as the last one I removed in the cool of winter. Got the PCM wiring back to original configuration. Started it, and the fan came on. Not a big surprise. Took it for a drive and the fan was working fine running off the PCM control.

Brother wanted to look inside the Fan Controller that has been on for about a year now, under previous ownership.

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[azjl#3]

looks like that pot leaked out? the 50v one. I would not rub your eyes after touching it.

 

[dank8307]

Oof. Which fan controller is this? I'm assuming RPM Extreme judging by the case.

 

[roaniecowpony]

There's a fair size following of these fan controllers. They work very well in controlling temps of the JL engines. These are made from programming an over-the-counter CAN bus module. It's a great idea and the programming is spot on. But the downside is that they are not environmentally protected, like all critical systems in your vehicle should be. If these fan control modules fail, the fan quits working and overheating is rapid.

If you are going to install these, I'd recommend you either run the wires through the firewall and mount it inside the vehicle, or protect the module. The latter is much harder.

If these are used with an interface harness like THAW developed, and protected, you should have a reliable system.

The other option is re-programming of the PCM, where the OEM fan controller resides in the sealed PCM. HPTuners, Diablo and probably others have that capability. Probably worth asking about this with Brad from BMP Calibrations, if you're discussing tuning with him.

 

[HHGadget]

As an RPM fan controller owner, this is concerning. Pardon my ignorance but can this unit be potted, similar to the axle locker sensors?

 

[Carguy34]

Mine did the same while on a wet trail. I pulled it apart and used an air compressor to blow it out. That was last October. I threw it inside of a nitrile glove I had and zip tied or taped it closed as a trail fix. Unfortunately, that trail fix is how it still resides. But, it is working still and hasn’t failed again.

 

[MPets]

Watching closly

 

[Terrymo]

What’s your diagnosis on the cause. Heat? Moisture intrusion? An isolated component failure? Some combination maybe.

 

[yokramer]

Why would a Sad Robot do this to that poor controller.

 

[siggy]

There's a fair size following of these fan controllers. They work very well in controlling temps of the JL engines. These are made from programming an over-the-counter CAN bus module. It's a great idea and the programming is spot on. But the downside is that they are not environmentally protected, like all critical systems in your vehicle should be. If these fan control modules fail, the fan quits working and overheating is rapid.

If you are going to install these, I'd recommend you either run the wires through the firewall and mount it inside the vehicle, or protect the module. The latter is much harder.

If these are used with an interface harness like THAW developed, and protected, you should have a reliable system.

The other option is re-programming of the PCM, where the OEM fan controller resides in the sealed PCM. HPTuners, Diablo and probably others have that capability. Probably worth asking about this with Brad from BMP Calibrations, if you're discussing tuning with him.

Yep Brad adjusted mine when tuning. Thanks for sharing on the fan controller and glad you got it sorted quickly!

 

[roaniecowpony]

What’s your diagnosis on the cause. Heat? Moisture intrusion? An isolated component failure? Some combination maybe.

Terry, I'm no electronic forensic engineer. But it looks like the circuit shorted from moisture/minerals and blew the capacitor.

 

[Terrymo]

Terry, I'm no electronic forensic engineer. But it looks like the circuit shorted from moisture/minerals and blew the capacitor.

Maybe not, but in your career and lifetime, I suspect you have seen enough to make a pretty strong educated guess. Thanks.

 

[Remorseless]

Womp womp. @bmpcamry09 new market segment for you - stockish tune with just fan adjustments for everyone who just wants the things to run a little cooler.

 

[dank8307]

From the photos you took and how water residue is on the PCB, I think the controller was laying down on its side or upside down, which definitely didn't help prevent water intrusion. Some RTV around the seams, dielectric grease on the connectors, and putting the module upright should mitigate this issue.

 

[bmpcamry09]

Womp womp. @bmpcamry09 new market segment for you - stockish tune with just fan adjustments for everyone who just wants the things to run a little cooler.

I can do all flavors. I have what I call a “stock plus” tune that leaves engine power and response stock but turns off stop start, changes fan points, and still gets transmission tuning. Case by case but it’ll be a cheaper option for those interested. Unfortunately it still requires the hoops to go through (unlock, bypass cable, etc)

I still think the fan controller is a viable option so long as it’s installed properly.

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