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William H

Electric Fan Controller for CJ7 with Mopar MFI Kit

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Hello Moses,

Just got back from my first Jeep Jamboree "Gateway to the Cumberlands". The good news is we had a great time and the bad news is we had mechanical trouble. Early on the first day a 3/4 to 5/8 heater hose adapter broke and spilled all the coolant. Trail repair was to bypass the heater core by looping the pump hose back to itself and refilling with tap water from the jerry can. The main problem then was the fan controller had also failed from the hot bath it received. Finished the day by manually starting and stopping the fans by physically raising the hood and connecting a hot wire to the fan relays. With these band aids in place and day 2 was to be a much tougher trail, I didn't want to pull up to the line not being a full strength and I decided to scratch for day 2.

My question would be the best solution to replacing and upgrading the controller. Research reviled that the existing controller "Hayden 3647" with radiator probe has a history of failures.

The HPC controller seems to have good reviews.

The controllers with the best reviews utilize screw in type sensors. The MFI kit uses the temp port in the thermostat housing and the OEM temp gauge uses the port in the back of the head. The top radiator hose is too short and curvy to install an inline adapter.

I am using external relays so current capacity of the new controller will not be an issue. Hoping for a robust solution that will not fail when wet.

How would you proceed?

The transmission, transfer case, and other equipment we worked on earlier is performing flawlessly. I really gave it a workout on the one run that I did complete.. :)

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Definitely not a Mall Crawler! 

Coming out of the creek at the Jamboree on Friday. There was at least an 18" step at the bottom, followed by a slick muddy hill. 23 in our group and I was next to last. Several had to be pulled. Made it on the second try.

Excellent camera work to freeze the tire tread and splash.

William

 

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Nice photo of the CJ, William!  First off, I'm not a fan of electric fans used in place of a mechanical, engine-driven fan.  For back country vehicles, I have always run a mechanical fan, ample radiator and a sensible shroud that will carry the entire cooling load of the engine.  You're putting out somewhere around 160 horsepower max, and that's 45 BTUs per horsepower—not a great amount of radiator/mechanical fan/shroud work to cool.

Are you using the electric fan exclusively or in conjunction with a factory mechanical fan?  Do you have room for a HD fan clutch and engine-driven fan?   Do you have a serpentine belt or V-belt drive system?

I'm sure there are reliable temp sensed switches to operate the electric cooling fan if you continue with that approach.  I would look at Jeg's or Summit Racing catalogs.  I'm a Summit Racing customer, as the Western distribution warehouse is only 32 miles away.  In fact, I stopped at Sparks this evening for some parts. 

These are Summit Racing items that caught my attention in a two-minute search of their website catalog:

https://www.summitracing.com/nv/parts/fbr-fb403/overview/ or https://www.summitracing.com/nv/search/part-type/fan-switches-thermal?retaillocation=nv&tw=fan&sw=Fan Switches%2C Thermal

In the second link you'll find a roster of controllers, switches and even a very simple sensor that goes on at 185-degrees F and off at 165-degrees F.  You'll get ideas from this list.  Derale and others have a lot of experience in this field.  

Let us know what you plan to do here.  If you need to share photos of your existing cooling system for feedback, please do so.

Moses

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Moses,

First this jeep had a long cooling problem history going back several owners. It would cool fine on the trail, but would heat up @ highway speeds, and especially on long inclines. Restricted air flow from the tall winch and the nearly 2000# of non OEM weight it carries was blamed.

I replaced the OEM style water pump with a high flow unit and I replaced the 4 core aftermarket aluminum radiator with a beefy 2 core direct fit aluminum model from Griffin Thermal Products. Cooling problem solved.

A dual fan low profile Flex-a-lite # 580 direct fit fan system with shroud came with the jeep when I bought it. Rated @ 2500 CFM total and 19.5A for each fan, it really moves the air. I just need a better way to control it.

I understand your preference for mechanical driven fans and your reasoning is well founded. Had a really rough time once when in extreme cold weather when large ice chunks took out my mechanical fan. Other times I wish I could have easily disabled the fan during deep water crossings. I guess it is a matter of choosing your poison. At some point I may choose to go back to a mechanical fan, but for now I will stay with the fans I have.

As you aware, there is not a lot of room between the motor and the radiator with the 4.2L I6.

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You can still see the bypass hose that was used after the heater hose let go on the trail Thursday. New hoses will be here in a couple of days.

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After searching the web for days, wading through all the hype and bull, the Dakota Digital PAC-2750 Controller seems to be a versatile and reliable unit. Have you any experience with this controller?

I have worked up a preliminary wiring diagram for a Dakota Digital solution using the existing fans and 180 deg. thermostat for your review and comment. A fairly simple and yet robust design with manual mission critical override control. Maybe a separate custom designed auditable alert triggered when approaching over temp. 

Fans operate at user adjustable different temps.
Proposed Fan #1 On 188 Off 180.
Proposed Fan #2 On 198 Off 190.

User programmable run on after engine off times.
Uses OEM Temp Gauge to receive temperature info, radiator probe no longer needed.
All electronics are dry mounted in Cabin Compartment.
Custom dash mounted fans running status led lamps.
Custom dash mounted Controller Override Switch.
Custom dash mounted Deep Water Fan Disable Switch.
Four fuses for maximum mission critical survivability in case of single fan failure or short due to wire chafing.

Visio-Fan Controller Adapter.pdf

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Might need to add a 2A fuse (F5) at the +12V input to the controller in case of controller short. This would still allow the "Controller Override Switch" to manually operate the fans. Haven't come up with a "simple" way to only allow the Override Switch to work when the engine is running without introducing another possible point failure and still the use of the "run on" after ignition feature. As drawn, accidental use of the Override Switch by a child or others could run the fans until switched off. After controller failure on the trail last Friday, having a manual fan switch out weights the draw backs.

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William, this is a very well thought out cooling system, nice job.  One cooling obstacle would be air flow restriction through the radiator core created by the double-fan's shroud system.  You can judge here, you know the efficiency and cooling effect.  Also, there is no full shroud, so the fans are not creating core air flow from above and below the fan assembly.  If that's not creating a cooling efficiency issue, it makes no difference.  Being practical, if the system works well, you've met the goal.

I do recognize the inline six's proximity to the radiator.  You're making the best of that limited space.  Your idea of a manual switch bypass makes good sense.  This will enable fan function if the controller fails.  Your wiring diagram looks thorough, I really like the idea of each fan having a different cooling range, that way there's not the extreme of full-on and full-off only.  Dakota Digital's controller allows experimenting with the temp ranges.

Dakota Digital is reputable and big in the custom vehicle market, they've been around for quite a while now with speedometer solutions, controls and other problem solvers.  I would trust the PAC 2750 product, especially with your fail safe manual switch override.  I like your thoroughness and wiring schematic, it should help others.  Thanks for sharing!

As a footnote, if your radiator and water pump efficiency are adequate, the fan system should not need to operate above 25-30 mph vehicle speed in most instances.  Try switching off the fans at road speeds to confirm this.  If the radiator core gets enough air flow and the GPM flow rate of the radiator meets the engine's needs, the fans should not need to run at road speeds unless ambient temperature or engine load are quite high.  If the fans are running, consider whether the fan assembly itself is blocking air flow through the core. 

Moses

 

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Moses,

Just got back from our Florida Sun Coast Vacation. Had a Great Time and the Weather was perfect! Highs in mid 80's lows in mid 70's and not a cloud each day. This is the view from our deck at the Seaside Inn on Anna Maria Island. Wife's payback for all her Jeep stuff patience.

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The 2 core Griffin radiator and Flow Cooler water pump has completely cured the overheating at highway speeds. BEFORE the fan controller failure, I had already confirmed the fans were not operating at highway speeds. Mission now is to make the fan system a reliable as possible.

I have made a little forward progress on the controller system redesign. Attached, you will observe the custom Override Switch and Fan Status LEDs housing. This box will be mounted to the bottom lip of the CJ dash and provide mounting and protection for the small switch and led's. I plan to mount the Dakota Digital controller just out of sight to the heater air box with heavy duty Velcro and leads long enough to allow removal and fine tuning of the temp thresholds and gauge sending unit settings. I expect it will take a little while to get the controller completely dialed in.

Front View

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Rear View (wire terminals)

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Inside view with bottom cover removed.

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Hope to be able to jump back into it starting next week. Also planning on supplying finished photos and updated "AS BUILT" wiring diagram.

William

 

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William, the R&R at Florida with your supportive wife looks like a wonderful and relaxing time!  Glad you did it...

The manual controller looks durable and simple.  Simpler the better.  This will be a dependable system before you're done, and I really like the manual override feature.  Smart and fail-safe!

Moses

  

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Moses,

Finally able to complete the fan controller install. Found out that the Dakota Digital PAC-2750 Controller is NOT compatible with the "Bi-Metal Strip" regulated OEM Temp Gauges found in CJ's. I elected to go with a Jeep branded AutoMeter electric gauge. Already had a hole in the dash. Seems to work quite well.

High Water Fan Disable Switch and AutoMeter Temp Gauge. Overlook the crooked rear ARB Locker Switch Label. Came with the Jeep that way and it is stuck really good to the dash and afraid to redo it.

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Fan Override Switch and Fan Status LED's mounted to the bottom edge of the dash.

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Fan Controller Velcro Mounted out of sight to the Heater Air Box.

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AS Built Wiring Diagram.

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Hope this helps others.

William

 

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This is beautifully conceived and implemented, William!  Your instrument panel and unique controls are exceptional.  I'm sure others will benefit from the examples and your schematic details!

Nice work...I like the circuit protection through fuses and relays.  It will be interesting to see what kind of actual amperage loads occur on the lighter gauge segments.

Moses

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Moses,

Verified current on the control segments.

F3: Key On, Fans Running, 500mA Max. Key Off: 2mA

F4: Battery Connection Surge 30mA, Key On 10mA. Key Off 2mA

F5: Key On 1.5mA

William

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William...Nice to have equipment that accurately measures surge draw!  A terrific control system, so well-engineered...Helpful to others, a true benchmark!

Moses

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Moses,

Thanks for the compliment. Really hope others are helped!

At 315 entries and 19 different trails the 2017 24th annual "Gateway to the Cumberlands" Jeep Jamboree was the largest JJ EVER! Really looking forward to the 25th annual next year.

Here are some very nice videos from this year. Nice drone work.

https://www.youtube.com/watch?v=F42AzDwOnW4&feature=share

https://www.youtube.com/watch?v=C_kNtTNUWTU&feature=share

https://www.youtube.com/watch?v=RP9ENNI1bKY&feature=share

This is where we came out of the creek on the Monkey Rock Trail. First try was with rear lockers only. Really nice still shots at the end.

https://www.facebook.com/bob.duncan.37/videos/10214373522594129/

William

 

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William, I am so into drone/aerial video angles.  (Ironically, just an hour ago I searched the Black Friday sales for a Mavic Pro drone.)  The trails come to life and perspective is so clear!  Really nice footage and editing by Ben Childers Photography!

Friend Dave Logan (Omix-ADA) has been doing the Jamboree program for years, I knew Mark Smith well and covered the original Rubicon Trail Jeep Jamboree program.  I shot the cover photo for Jp magazine's first issue along the Rubicon Trail, friend Keith Buckley (Chief Research Engineer at Goodyear) and my teenage son Jacob (now 36 and a manager at Amazon) smiling with the windshield down on a new Jeep YJ Wrangler.  Lots of history here. 

What I like best is that folks are having fun and experiencing the trails and environments that built our country.  The drones illustrate and engage us that much more.

Fun...That's what your Jeep CJ is ultimately about...

Season's Best!

Moses  

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