The Dakota Digital PAC-2800BT

Dakota Digital PAC-2800BT Cooling Fan Controller

This blog post is going to show you how to use the Dakota Digital PAC-2800BT to control your cooling fan with the Infinitybox system.  The PAC-2800BT is a powerful controller that lets you program the temperatures that turn on and turn off your cooling fans.  You have the flexibility to use any temperature sender, take in OBDII data from a modern ECU, even interface with the VHX & RTX gauges.  We’ve blogged before about wiring the VHX and RTX gauges with the Infinitybox system.  Click on the links to learn more.

There are multiple advantages to using the Infinitybox system with the Dakota Digital PAC-2800BT controller.  First, you can eliminate the external relay and the fuse.  These are built into the POWERCELL.  Next, you can streamline your wiring.  The PAC-2800BT would be located behind your dash, near the MASTERCELL.  The power for the fans comes from the front POWERCELL, which is located strategically where you need it in the car.  Lastly, the POWERCELL has the ability to soft-start the cooling fan.  This decreases the in-rush current to the fan and lets you drive a larger fan with a smaller gauge of wire.  You can read more about this at this link.

As always, we strongly encourage you to read and understand the manuals for anything that you are installing in your car.  Dakota Digital has a very detailed manual for the PAC-2800BT.  You can access it by clicking this link.  Also, this blog post is going to cover the wiring between the Infinitybox system and the PAC-2800BT.  This includes ignition power, the cooling fan triggers to the MASTERCELL and the cooling fan output from the POWERCELL.  Follow the Dakota Digital instructions for wiring battery power, ground, the temperature sender and the other optional features of the PAC-2800BT.

The following picture shows the connections between the Infinitybox MASTERCELL and the POWERCELL for the PAC-2800BT.

Picture of a wiring diagram showing how to wire the Dakota Digital PAC-2800 BT with the Infinitybox 20-Circuit Kit

Picture of a wiring diagram showing how to wire the Dakota Digital PAC-2800 BT with the Infinitybox 20-Circuit Kit

First, you need to get ignition or key-on  power to the PAC-2800BT.  This is going to come from the POWERCELL output for the ignition.  This is output 3, the light-green wire on the front POWERCELL in most systems, .  Please check your specific configuration sheet to confirm.  You can going to bring this ignition power to the IGNITION terminal on the PAC-2800BT module.  You are going to tap off your POWERCELL ignition output to get this power.  You can splice into this wire or you can use our Splice Saver kit to create an ignition junction point.

Next, you are going to connect your MASTERCELL cooling fan inputs to the triggers on the PAC-2800BT.  In most systems, your cooling fan is input 10, which is the blue wire with the green tracer.  Check your configuration sheet to confirm.  If you are using only one cooling fan, Dakota Digital tells you to use the FAN LOW terminal on the PAC-2800BT.  We strongly recommend that you install a diode in-line between the MASTERCELL and the PAC-2800BT.  This should be a 1N4001 diode that can be purchased easily from Amazon.  The orientation of this diode is critical and the system will not work correctly if it is wired backwards.  The diode lead on the side with the stripe should be connected to the PAC-2800BT.

Lastly, you are going to connect your POWERCELL output for the cooling fan to the wires on the fan motor.  The other wire on the fan motor should be connected to a good chassis ground.   This link will get you more details on wiring the cooling fan with the POWERCELL output.

The PAC-2800BT gives you the option to control two separate cooling fans.  If you want to use a second cooling fan, you would simply repeat wiring an unused MASTERCELL input to the PAC-2800BT and an OPEN POWERCELL output to your second cooling fan.  In most of our kits, output 8 on the front POWERCELL can be used as an auxiliary output.  You can use this one to power your second cooling fan.  See your specific configuration sheet for more details.

Here is how all of this works.  The PAC-2800BT takes in the temperature data from the temperature sender, the Dakota Digital gauge controller or the ECU via OBDII.  If the temperature it reads goes higher than the value that you programmed in it, it grounds the MASTERCELL input for the cooling fan.  This turns on the cooling fan input.  The MASTERCELL sends a command to the POWERCELL in the front of the car to turn on the output for the cooling fan.  When the temperature drops below the set point that you programmed in the PAC-2800BT, it turns off the MASTERCELL input for the cooling fan.  The MASTERCELL sends a command to the front POWERCELL to turn off the fan.  It is that easy.

If you choose the option to use two cooling fans, the PAC-2800BT will manage both fans together to control the engine temperature.

There is a PDF copy of this wiring diagram available on our website.  Click this link to download it.

Give our team a call at (847) 232-1991 if you have any questions about wiring the Dakota Digital PAC-2800BT with our Infinitybox system.  You can also contact our team directly by clicking this link.

Jeep CJ7 Wiring Series- MEGA Fuse Location

Over the next few videos, we’re going to continue our theme on good planning.  Specifically, we’re going to talk about picking the best locations for the major components that come with your Infinitybox system.  We’re installing our 20-Circuit Kit with inLINK and inRESERVE in our 1979 CJ7.  To get the most out of our install, we want to pick the best locations for the MASTERCELL, the front & rear POWERCELLs, the MEGA fuse holder and the inRESERVE solenoid.  We’ve broken this up into 5 different videos, talking about what you need to consider for each part.  This video covers picking the best location for the block of MEGA fuses that comes with your 20-Circuit Kit.



Everything starts with running primary power from the battery.  The POWERCELLs get powered by cables that connect back to the positive terminal of the battery.  These cables need to be protected against short circuits by fuses.  Your 20-Circuit Kit includes a block of 4 high-current MEGA fuses to protect the four 8-AWG cables that bring battery power to the POWERCELLs.  If one of these cables was to short to ground, the MEGA fuse becomes the weakest link in the electrical chain.  The fuse opens to protect the cable from damage.  You want the MEGA holder to be mounted as close to the battery as possible to minimize the length of unprotected cable.

We’re going to mount the MEGA fuse block right in front of the battery, under the hood.  There is a flat spot on the inner passenger fender that would be a great place.  It is a short run of cable from the positive terminal to this location and we can easily route the 8-AWG power cables to the front & rear POWERCELLs.  Watch this video to learn more about these and see where we’re mounting the MEGA fuses in the Jeep.

We are also installing our inRESERVE battery management solenoid in the Jeep.  The best location for the inRESERVE solenoid is usually right next to the block of Mega fuses.  This picture shows you how the Mega fuses go hand in hand with the inRESERVE battery management kit.

This diagram will show you the overview of the Mega fuses in the Jeep and show you how they connect to the battery, the inRESERVE solenoid and the 8-gauge power cables that feed each POWERCELL.

Infinitybox Jeep CJ7 Wiring Diagram- Cell Locations and Primary Power Routing

Infinitybox Jeep CJ7 Wiring Diagram- Cell Locations and Primary Power Routing

You can download a PDF copy of this diagram by clicking this link.

Picking the best location for the MEGA fuse holder will get you a safe and reliable electrical system in your car or truck.  It will also make running the power cables to your POWERCELLs easier if you plan in advance.  Keep watching for more in our 1979 Jeep CJ7 Install Series.

Be sure to subscribe to our YouTube channel and click the bell icon so you get notified when we post new videos in the series.

Click on this link to get to the main page for the 1979 Jeep CJ7 wiring project.  You can find all of the videos on one place there.  

You can also click here to contact our technical support team with any questions about your car or truck wiring project.  


Our 20-Circuit Kit is the core to the electrical system in your car.  It is more than just a wiring harness.  It is a universal wiring system that gets you the most advanced, functional and reliable electrical control on the market.  The 20-Circuit Kit starts with our MASTERCELL, which connects to your switches.  It also includes two of our POWERCELLs, which we call the muscles of your system.  The MASTERCELL sends commands to the POWERCELLs to locally power your lights, ignition, starter solenoid, cooling fans, fuel pumps, horn and other accessories.  We’ve talked about the MASTERCELL in more detail in a recent blog post.  You can link to that here.  This post is going to cover more details about our POWERCELL.

The 20-Circuit Kit includes 2 POWERCELLs.  Each POWERCELL can control 10-outputs.  One POWERCELL is for the front of the car, the second is for the rear of the car.  The front POWERCELL is set up to control your headlights, high-beams, turn signals, front running lights, horn, cooling fan, ignition power, starter solenoid and dash power.  The rear POWERCELL is set up to control your rear running lights, turn signals, brake lights, fuel pump, back-up lights, dome lights and other accessories.

Connecting your loads to the POWERCELL is very easy.  You run the output harness from the POWERCELL to your light, fan, pump or other accessory.  You cut our universal harness to length.  You connect our output wire to the wire on your load.  That’s it.  Click on this link to get more details on connecting your POWERCELL outputs to the electrical loads in your car or truck.

You put the POWERCELLs in the car were you need them.  This lets you eliminate size and weight of the wiring harness in your car.  The installation is simpler because the runs of wire are shorter and troubleshooting is easier.

The POWERCELL is a remote fuse and solid-state relay box.  The fuses that you need to properly protect your wiring harness are built into the POWERCELL.  You do not need to add separate fuses.  Also, the solid-state relays that control your loads are built into the POWERCELL.  Each output can carry up to 25-amps continuously so you do not need to add external relays to control your lights, fans, pumps and other accessories.  Also, we don’t use mechanical relays in our POWERCELLs.  Our outputs are controlled by solid-state MOSFETs.  This are rugged and reliable and give you tons of benefits over traditional relays.  Check out this link to learn about some of the advantages of a MOSFET.

This video walks through more of the details of the Infinitybox POWERCELL.

You can easily add extra POWERCELLs to your 20-Circuit Kit if you need to expand the output capacity beyond 20.  Each additional POWERCELL gives you 10 more outputs to your Infinitybox system.  The POWERCELL kit includes the POWERCELL plus all of the harnessing required to connect to your existing 20-Circuit Kit.  You can learn more about the POWERCELL kit by clicking this link.

We have the solid model for the POWERCELL available to our customers to help with their planning and mocking up process.

If you want to purchase our Infinitybox system or have technical questions, you can click on this link to contact our team.


Now it is time to connect the POWERCELL outputs to your loads in the car.  When we talk about loads, we refer to the things that you need to power to make the car work.  These include your headlights, turn signals, ignition systems, starter solenoids, fuel pumps, cooling fans, horns, lights, etc.  All of these loads are going to the connect to each POWERCELL output to get their switched battery power.

This post is going to cover the basics of wiring the POWERCELL outputs.  We will publish several specific posts that will go through the details of how to wire your turn signal outputs, wiring your ignition and starter, wiring cooling fans and other loads.

The automotive electrical system uses a grounded chassis.  This means that each load gets its switched power from some power distribution device.  In your case, it is your POWERCELL.  Current flows from the POWERCELL to the load.  To complete the circuit, the load needs to get connected to ground, which is typically your chassis.  The chassis is connected to the negative post of the battery.  This is how the circuit is completed in your system.

Another thing to remember about your Infinitybox system is that the switches connect to the MASTERCELL.  Your loads connect to the POWERCELLs.  There is no connection between the switch and the load.  That connection comes from a data command sent from the MASTERCELL to the POWERCELLs.  When you turn on a switch, the MASTERCELL tells the POWERCELL to turn on an output.

Your kit includes an A & B output harness for each POWERCELL.  If you have our 10-Circuit Kit with one POWERCELL, you have one each of the A & B harnesses.  If you have our 20-Circuit Kit with two POWERCELLs, you will have two of each.

This picture shows you the POWERCELL A output harness.  It has the wires for outputs 6 through 10.

POWERCELL A Output Harness

POWERCELL A Output Harness

This picture shows you the POWERCELL B output harness.  It has the wires for outputs 1 through 5.

POWERCELL B Output Harness

POWERCELL B Output Harness

Yes, we get that it seems that the A & B designations are reversed for these harnesses.  That designation came from the original layout of the POWERCELLs from our early beginnings.  These designations have stuck and changing over a decade of documentation would be tough.

Please note that the A & B connectors are interchangeable in the POWERCELL output sockets.  A lot of initial problem calls that we get from customers come from the fact that they have these harnesses reversed.  Make sure that you are plugging the correct harness into the correct socket.  The manual that came with your kit shows you the correct orientation.  This picture also shows which connector socket is A & B.

Illustration of Infinitybox POWERCELL labeling output connectors

Illustration of Infinitybox POWERCELL labeling output connectors

Once you get the connectors plugged into the correct sockets, you need to properly ground the POWERCELLs.  Each of of the output harnesses have a black wire.  Both of these black wires need to get grounded to the chassis.  This is to properly ground the electronics in the POWERCELL.  Make sure that you have a good metal-to-metal connection between these ground wires and the chassis.  You must make sure that you remove all dirt, rust, oil, grease, paint and powder coating from this connection.

Next, it is time to start connecting the POWERCELL output wires to the loads in the car.  Remember that your configuration sheet is your road map to do this.  You can review our previous blog post about the configuration sheet as a refresher by clicking this link.  The configuration sheet is going to identify the specific POWERCELL output wire by color for each load in the car.

You are going to run the POWERCELL output to the load.  From there you must connect the POWERCELL output wire to the wiring on your light, fan, horn, fuel pump, etc.  There are many different ways to do this.  People will argue advantages of one method over another.  If done correctly with the right tools, they are all good methods.

One of the easiest ways is to butt splice the POWERCELL output wire to the wire on your load.  For example, you cooling fan will probably have two wires coming from the motor housing.  You can use a butt splice connector to connect the POWERCELL output wire to the wire on the fan motor.  This picture shows an example of a butt-splice.

Picture showing example of splicing wires in our 1967 Mustang Install of the Infinitybox wiring system.

Picture showing example of splicing wires in our 1967 Mustang Install of the Infinitybox wiring system.

The team at Waytek Wire have a great post on their blog called “Splice Connectors 101”.  In this article, they walk you through the basics of splicing wires together.  Click here to read this article. 

What is important is that you use the correct crimp tool and you properly seal the joint.  This seal can be done with heat shrink tubing or you can use butt crimp connectors that already have a heat-shrink jacket over them.  Companies like Waytek and Del City are great sources for the right tools and materials.

Another option is to solder the wires together.  A lot of customers swear by this method or a combination of butt-splicing and soldering.  The advantage is that you get a metallurgical connection between the copper strands of both wires.  Some will argue that this is stronger and more reliable than a pure mechanical crimp of a butt-splice.  Just like the butt-splice mentioned above, this joint must be sealed preferably with heat shrink.  The only warning with soldering is that if too much solder is applied to the joint, it can wick up the strands of the wire flowing away from the joint.  This wicking can make the wire more rigid and susceptible to fatiguing if the joint is stressed mechanically.  Just watch the amount of solder that you are applying to the joint.

The last is to put connectors on both ends of the connection.  This is the most time consuming and costly, but it has advantages down the road if you need to remove the load for maintenance.  There are many different options for connection systems.  Deutsch connectors are very popular in racing.  They are rugged, durable and proven.  Delphi Weatherpack connectors are another option.  They have been proven in the field for decades and are a cost effective option.  You can purchase Weatherpack kits from many different sources that include the proper tools to crimp the terminals.  Here is an example of a Weatherpack kit that includes the tool.

If the POWERCELL output harnesses are not long enough, you can easily extend them using any of the connection methods mentioned above.  You must make sure that you use the right size of wire and the right insulation type.  We use 14-AWG wire for all of the POWERCELL outputs.  This will carry 32-amps continuously, which is very conservative for most aftermarket and racing applications.  We use wire with TXL insulation.  This is a cross-linked wire designed for the automotive environment.  It is oil, dirt, chemical and abrasion resistant.  You can source extra 14-AWG TXL wire at this link.  We can also create custom harness lengths.  Contact our sales team for details.

Just a few last comments about wiring the POWERCELL outputs.  Stay away from Home Depot.  We say this as a joke but it is important.  The same materials that you’d use to wire a house have no place in the car.  That means no wire nuts, extension cords or electrical tape to make connections.  Use only tools and materials that are designed to handle the automotive environment in your car.

Keep watching for the next posts that will detail wiring POWERCELL outputs to some of the specific systems in your car.  If you have any questions, please click on this link to contact our team.

Picture of the Littelfuse Minifuse

Fuse Sizes

Here’s the answer to another popular question that we get from customers when they’re wiring their cars with our Infinitybox wiring system.

What size fuse should they use for the different outputs on the POWERCELL?

Remember why the fuse is there…  it is there to protect the wire not the end load.  There is no need to protect the headlamp with a fuse but you do need to protect the wire going to the headlamp.  A fuse is a thermally operating device that is intended to be the weakest point in an electrical system.  If the system is drawing too much current, you want the fuse to open intentionally, protecting the rest of the system.  You never want your wire to be the weakest point in your electrical system.

Fuses are designed to protect against two kinds of faults.  The most common is a short circuit.  Let’s say that the wire to your headlights gets pinched against the chassis and breaks the insulation.  You now have a very low resistance path to ground which will carry a lot of current.  You want the fuse to open before the insulation on the wire gets hot enough to cause damage.  The other scenario is a low-overload.  These are usually resistive connections to ground that will still carry enough current to damage the wire.

To properly select the size of the fuse that you need to consider two things.

First, what is the minimum gauge of wire that the fuse needs to protect?  All of the output harnesses on the Infinitybox POWERCELLs use 14-AWG wire.  But, if you spice our output wire to a wire with a smaller gauge, you need to size the fuse to protect the smaller wire.

Second, you must understand the current draw for your load connected to the output wire.  The fuse must be large enough to handle the steady-state current of the load plus any inrush that the load may have.  Anything inductive (motors, coils, solenoids, etc) have inductive inrushes that could be up to 10 times the steady-state current draw.  Incandescent bulbs also have inrushes.  Remember that the resistance of the filament in the bulb is a function of its temperature.  When the bulb is cold, the resistance is low so it can carry more current.  As the filament heats up, the resistance increases as does the current flowing through the bulb.  The inrush through a light bulb can be 5 to 10 times its steady state current.

For those who want to learn more, this link will take you to a good document from Littelfuse that talks about how to properly size a fuse for a specific application.

LED lights draw far less current than their incandescent brothers and have practically no inrush.  You can use a much smaller fuse.

Here is a simple chart to use as a reference for sizing your fuses.

Headlights- 20-amp
Starter solenoid- 20-amp
Ignition- 25-amp
Fuel pump- 25-amp
High-Beams- 20-amp
Turn-signals- 15-amp
Cooling fan- 25-amp
Power window regulator- 20-amp
Lock actuator- 15-amp
Parking lights- 15-amp
Horn- 10-amp

Use this chart as a guideline to pick your fuse sizes.  You may need to adjust depending on the gauge of wire connected to your load and the specifics of your load.  Remember, these are guidelines.  If you change the gauge of wire that is included in the kit, you have to reevaluate the size of fuse required.

Contact our technical support group at (847) 232-1991 for more details.

Picture of the Littelfuse Minifuse

Why A Fuse?

We get this question a lot.

Why do the POWERCELL and inMOTION cells use fuses to protect the outputs?  Some say that we’re already using smart MOSFETs, why not rely on them to protect against over-current on the output wires?  Others ask, why not use circuit breakers?  There are several important and practical reasons why we rely on a traditional fuse to protect the outputs on our Infinitybox hardware.

With respect to MOSFETs, they are tried and true technology.  They are used in practically every application for switching and current control.  The MOSFETs used in the POWERCELLs are automotive-grade and designed to carry up to 270-amps.  The chances of them failing in a typical customer car are minute.  However, if a MOSFET fails, it doesn’t fail gracefully.  If a MOSFET were to fail, it fails resistive.  That means that they are going to generate a significant amount of heat, quickly.  No intelligence built into the circuitry can interrupt the current flow if the silicon die in the MOSFET package has become a resistor.  In that case, the fuse is your last line of defense to protect the system from thermal runaway.

You can use the same logic for inMOTION.  It has sensors on the board that monitor the total amount of current flowing out to the load.  inMOTION already shuts off the relay coils when it sees too much current, why not rely on that alone without the fuses?  The practical reality is that a common failure mode for relays is for the contacts to weld together, especially in inductive motor application.  If this were to happen, no intelligence on the inMOTION board can open the circuit.  Again, the fuse becomes the last line of defense.

With the above being said, you can see the need for some circuit protection component in the system if other components fail.  That leads to the debate between fuses and circuit breakers.  Circuit breakers can certainly do the job, however a fuse will out perform a breaker in all categories.

  1. Fuses are more cost effective than circuit breakers.
  2. Fuses are smaller and package better than circuit breakers.
  3. Fuses have better low-overload protection characteristics than circuit breakers.  This is very important in cases of resistive shorts like a failed MOSFET.
  4. Fuses respond quicker than circuit breakers under short-circuit conditions.

Most importantly, a fuse drives better end user behavior than a circuit breaker.  At the end of the day, there is a reason why a fuse opens or a breaker trips.  A motor has failed.  Insulation on a wire has shorted to ground.  An electronics module has failed.  In all these cases, you do not necessarily want to blindly reset a breaker and keep on driving.  The cause of the over-current condition needs to be identified and fixed before resuming normal operation of the vehicle or equipment.  Otherwise, more severe thermal events can occur in the wiring harness causing damage or injury.

See our blog for additional posts on proper fusing and other circuit protection lessons.  If you have any questions, reach out to our power distribution experts at (847) 232-1991 or email our team at  You can also click this link to contact our team directly.