Switch Pros SP9100 Installation

The Switch Pros SP9100 is a great way to control your lighting and accessories. It is widely used by many enthusiasts and professionals in the offroad/overland community. It was only a matter of time before the SP9100 was adapted into the New Defender by those looking for serious control over their lighting and accessories.

This guide will help you through the process of installing the switch panel into your Defender using our brackets but can also be applied if you decide to mount your switch panel elsewhere. We highly recommend this installation to be done by a professional or at least by a DIYer who is mechanically inclined. This installation can take from a few hours to a weekend depending on your skill level and accessories you are installing.

Please be aware that this guide is based on a p400 Defender with air suspension. Some minor differences will be present if you have a p300 Defender and/or if you have springs instead of air suspension.


Tools for this installation can vary but here’s a list of most tools we used during our installation

  • ¼”  ratchet
  • Magnetic 10mm socket (important)
  •  ¼” extension 12 inches long
  • 7mm socket
  • Flat head screwdriver
  • Wire cutters
  • Long needle nose
  • Wire strippers and crimpers
  • Long straight pick
  • Plastic panel/trim popper
  • Razor blade
  • Drill with a 5/16 drill bit or a step drill bit
  • Flash light


  • 125A stud mount amg fuse (optional, see step 14 for details)
  • HHTR micro-ll fuse tap
  • ATR mini fuse
  • Wiring for ground wire (about 6 ft)
  • Marine heat shrink tubing
  • 2 m8x1.25 nuts
  • Spade crimp connector


Remove both front cowl covers shown on the picture. Pretty easy to do. 6 plastic screw clips and 4 flat head bolts.


We’ll start off with the hardest part. Switch Pros requires you to run the module’s ground directly to the negative post of the battery. Running your ground to the chassis can cause weird electrical gremlins due to EMF. Unfortunately. the battery on the defender is under the passenger seat and makes it tricky to run a direct wire to it. The shortest route we found was under the fuse panel under the passenger side cowl. You will need to remove the panel in front of the fuse box (marked with a red X). It’s a total of 6 10mm bolts.  Two in the front circled in red, two on the side marked with a red arrow, and 2 on the back side marked with a blue arrow.

Firstly you will need to cut off the zip ties that hold the positive cable. Marked with red ovals are the location of the 2 zip ties that need to be cut off. Do not cut off the heads! Our picture shows them already removed. Do not cut off the one in blue. Circled in yellow shows a nut that was removed. You do not need to remove this nut. Circled in red is one of the bolts that needs to be removed.

Now you’ll have to loosen up the tubing for the right air strut and the hoses attached to the back side of the panel we are removing. These pictures show you which needs to be loosened in order to allow the panel to be removed.


Remove the front 2 bolts circled in red. Remove the 2 bolts on the side marked with red arrows. Notice the lower bolt holds the water pipe and is different from the others.

Step 4

Look behind the panel and locate the bolt marked with a blue arrow. Remove it.

Now pull out your flash light and look deeper. You’ll see a hidden bolt marked with a blue arrow. This is where your extension and magnetic 10mm socket will come in handy.

Here’s a picture demonstrating our 10mm magnetic socket and why it’s perfect for the job. If you don’t have one and can’t get a hold of one, you can try fishing it out with a magnetic pick up tool once loosened. Careful not to drop it.

Here shows the difference in hardware. The one circled is the bolt for the coolant pipe.

Step 5

Now with the bolts removed, we can make way for the panel’s removal by carefully placing the air line for the strut to the left of the cover marked with a red X. Also important to mention, when removing the panel or reinstalling, be careful not to put too much pressure on the area marked with the red X as it can break.

In order to pull the panel off, you need to pry back using a flat head screwdriver on the area you see in the picture. This other panel goes over the panel we are trying to remove and by prying it back we can make enough room to pull it up and off. While prying pull the panel up until it is removed.

Here you see a better angle of the process with the panel half way removed.

Here’s a picture showing the panel removed and the fuse box fully exposed.

Step 6

Under the fuse box you will notice a harness that runs into the cabin marked with a red arrow.

On the boot of the harness you will find a nipple (circled in red). You will need to cut the head of that nipple in order to run your ground wire into the cabin and to the battery. Best way is to use a razor blade, just be careful not to cut your fingers.

Go under the passenger foot well and remove the cover under the dash. To do so you’ll need to remove 3 7mm bolts shown circled in red. Make sure to disconnect the foot well light when removing the cover.

Once you remove the cover you can see the hole on the boot you made earlier. (circled in red)

Step 7

Run your ground wire out the firewall through the hole you created pushing it out from the inside of the vehicle. You can have a second person pulling from the engine compartment to make it easier.

 Pull out enough so you can reach it once everything is put back together. Pictures shows 2 ground wires we are using. You only need 1 ground wire but we optioned to have a second wire for future projects. You can also run a gmrs antenna cable through this hole or any other accessory wiring you may need. We feel this is the cleanest possible way to run wiring through the firewall. It is right above the max wade depth but if you’d like to water proof it, you can use marine heat shrink tubing over the nipple and wiring of the boot. Marine heat shrink tubing expels a sealant when heated for a weather proof seal. Alternatively you can use RTV to seal it instead.

We will be running the wiring under the passenger right footwell panel. The red arrows show where you will be tucking it under.

First pop off the door sill panels by using your plastic panel poppers as shown on the picture.  You will not need to remove it completely, just need to lift up a portion of it. Start on the right and work your way to the left. If your Defender has the light up door sill, unplug its connector to make more room. Check to see if you left behind any clips. If you did, remove them and reinstall them on the door sill panel before reinstalling.

Now start tucking in your wiring under the right footwell panel.

Stuff the wiring into the channels as shown on the picture marked with the red arrows.

Run the wiring up to the split in the carpet. Remove the battery cover under the seat and tuck the wiring under the carpet as shown in the picture.

Run the wiring under the seat and into the battery compartment as shown.

Use a spade crimp connector to connect to the stud on the negative post. (Ignore the change in wiring color, this is because the picture is of another Defender we installed a SP9100 into)

This Picture illustrates the ground wire attached to the negative post by using the stud on the negative cable connector.

Once the ground wire is connected to the negative post of the battery, you can go ahead and reinstall the battery cover, door sill panel, and under dash cover.


Now back to the engine compartment, grab the panel that we removed earlier and let’s get it ready to reinstall. Clip off the zip ties leaving only the heads attached to the panel.

Here’s a close up of the heads still attached to the panel. You’ll use the zip ties provided in the SP9100 installation kit. Insert the zip ties through the heads. You will use these zip ties to tie the cable as it was previously attached.

Reinstall the panel in the reverse order of steps 2-5. Once installed, secure the battery cable as shown using the zip ties you installed.


Grab the grommet circled in red. You’ll be cutting out the top to make room for the harness on the module. Using a razor blade was the easiest way for us. Just watch your fingers.

This is about how ours looked after cutting out enough to have the harness fit. Hopefully yours looks better. Reinstall the grommet.

Install the module and bracket. Refer to the Saltek SP9100 Bracket Installation for more details on this install.


Grab the harness for the module and install the wiring sleeve. Separate the white wire and install its own sleeve. Look closely at the picture as it shows how it should be. The sleeves are provided in your SP9100 kit.

We used heat shrink tubing to cover the ends of the sleeve to keep them from fraying apart. We recommend you do that as well for a cleaner look. Heat shrink tubing is not provided by Switch Pros so you’ll have to source your own.

Install the harness onto the module and route the harness over the panel, over the grommet you cut out on the last step.


Locate the ground wire from the harness. It will have an eye terminal crimped at its end.

 Cut the eye terminal off and splice the ground wire from the harness to the ground wire you attached to the battery using a crimp provided by Switch Pros. Keep in mind these crimps can be heated and will shrink to create a weather tight seal. (don’t be fooled by our picture. The wire is black, not white. The light was just hitting it just right for the camera to catch it over exposed)

Remove the fuse box cover and locate fuse F13. Install the add-a-circuit to it and use a 5 amp fuse for the new circuit being installed.

Run your light blue wire through the fuse box boot and crimp it to the add-a-circuit wire as shown on the picture. This is your ignition source which your SP9100 will depend on to operate. Close up the fuse box on move on to the next step.


We will now focus on installing the harness for the switch panel.

Locate the under dash cover on the driver side. Remove the cover by removing the 3 7mm bolts circled in red.

From the engine bay, locate the steering shaft boot which is located on the driver’s side firewall. Use your big straight pick to puncture a hole at the top as shown on the picture.

Looking from under the dash, you can see where the pick punctured through. (circled in red)

Now guide the switch panel harness through the puncture. Push the harness through the boot from the engine bay. You’ll need a second person to help you with this. You can use long needle nose pliers to assist pulling the harness through.  Insert them through the puncture you created starting from the inside of the cabin and spread them open to stretch out the puncture a bit. Have a second person insert the connector between the grippers of the pliers. Grip the connector on the harness and pull it through into the cabin.

Run the harness from the boot all the way up to the cubby. Follow the installation guide for the brackets Saltek SP9100 Bracket Installation

Now at the engine bay side, run the harness through the cowl and through the bottom of the foam piece circled in red. Connect the harness to the module. Make sure to secure the harness using zipties along the cowl to clean it up as much as you can.

Huge warning for the next step. It will require you to tap into the vehicles harness. Land Rover dealers can use this as an excuse to void you warranty for any lighting or electrical concern. We know there is a current issue with the day time running light halos going out. The dealer can void warranty on it even though it’s not even on the same circuit and we know it didn’t create that fault. The SP9100 doesn’t need the following step to operate so for those reasons we will leave the following step as optional.


The following step is for connecting the white and pink wires. The white wire is used by the SP9100 module to sample when the lights are turned down. This will lower your display lighting when the lights are turned on. The pink wire is a trigger wire and is user dependent. An example for its purpose is to turn on your light bar when you hit your high beams or to turn on your rear flood lights when you go into reverse.

You will now run the white wire we separated on step 10 behind the power junction as shown on the picture. We used a blue line to illustrate where that harness will run through. Ziptie the wire to the harness running along the blue line to secure it in place. Run your white wire all the way to the front right marker. Trim off any excess wire.

Use the T-tap provided by Switch Pros and install it on the marker wiring. Use the white and brown wire. The picture illustrates how it should look. Reconnect the marker.

Since the pink wire is user dependent we will leave it up to the user to find a place for them to tap into. If you need help, Submit a comment with your request and we will do our best to find the optimal location to tap into for your application.


Remove the cover for the power junction shown in the picture circled in red on the previous step.

You will now have 2 choices for connecting the power cable.

This shows you one option where you have to cram the cable to the stud that carries power. With this method you can use the provided fuse that is already attached to the cable.

This second option is a much cleaner method using the optioned 125 amp fuse that you’ll have to source yourself.

The second option will require you to remove the attached fuse and use the longer side of the cable.

Whichever method you decide to use you’ll need to drill out the smaller eye connector on the cable. A 5/16 drill bit will fit snug. Bolt the cable to the junction.

Clip off the cover on the designated area as shown and reinstall. Connect the cable to the module.

That’s It! You are now ready to wire up your lights and accessories. Use the Switch Pros wiring diagram to finish your installation. Don’t forget to reinstall your cowl covers.