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Switch Pros install - finding ignition / Accessory tap in Engine Bay

ebob9

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I've been working to get a new Switch-Pros 9100 installed in my Ranger. I wanted to post this log to partly help anyone else who might run into similar issues, and partly get feedback on my method.

WARNING: I'm often an idiot, and you might break stuff if you follow what I did. This is here for info/help with no warranty or guarantees.

I bought the kit from SDHQ to make the install easier - and it's a great kit.

However, the hard/fun part has been getting an Ignition source for the blue wire. The blue wire appears to just be a 12v sensor, and there's no real load on the circuit.

A lot of people have had varying suggestions - most along the lines of:
  • Use a piggyback fuse and run a wire through the seal on the Battery Junction Box (Engine fuse box.)
  • Run a wire through the firwall and use a piggyback fuse in the Body Control Module (Driver footwell fuse box.)
I didn't like either of those options.. so I decided to take a different route. I decided to tap an ignition switched circuit wire past the BJB (Engine fuse box.)

I started a thread here to find out wire colors/circuits - found the info myself and updated my own thread.. but the data here is what I used to make this work.

Armed with that info, I did some tests on my fuse box to find out which fuse would be a good candidate to tap. I finally decided to tap F19 - the Power Steering Control Module fuse. This fuse is ignition switched and came on as I expected and desired the ignition lead to work.

Step 1.png

step1b.webp


Now, If I'd done a piggyback connector - I could have just added a micro3 connector and been done. But I decided to go the complicated route. I pulled the connectors and tapped the wires under the fuse panel.

The connector I was going to tap for Fuse 19 was Connector 1035A - the left connector as you look at the fuse box from the front of the hood.

step2c.png


The pin I needed to tap was Pin 19.. however you'll see above I also circled Pin 30 here's why:

step2b.webp

Unfortunately for me - Pin 19 AND Pin 30 are both a 20-gage brown wire with a white stripe.. dang. This is solvable though, but we'll need to do some trial and error.

First, I disconnected the negative lead on the battery (Important!), then Fully removed the interior fuse box. This isn't trivial but it's common - you'll need to do this if you ever have to change some of the bottom fuses. There's a good thread here on how to do this, with a damn good YouTube video of the process.

With the fuse box removed, you can see the 1035A and 1035B connector/harness cables run under the fuse box.
IMG-7055.jpg


I cut the zip tie securing both connectors, and I removed the tape from the 1035A connector - it has a plastic shield taped around it.
IMG-7057.webp


Once the tape is gone and the shield is removed - yup, there are two 20-gage brown-with-white stripe wires! Note - these almost looked grey, not brown..
IMG-7058.webp


So what to do? The way I figured out the correct wire was to tap one, then use a multimeter continuity test and see if the tapped wire was Pin 19 or Pin 30.

The taps I used were Posi-Tap wire taps, as they are less "destructive" to the cables (in my opinion.) Not water tight, however.

Well, the first one I picked and tapped was of course Pin 30. So I untapped it and taped over it to be safe. Here's a pic of the wrong wire (electric taped) and the correct wire (under finger.)
IMG-7064.webp


Tapping the other wire and success, the meter beeped on Pin 19.
IMG-7065.jpg



Next, I routed the Switch-Pros blue wire under the plastic BJB mount - where the harness wires were run. Easy to get it it there by going along side the battery.
I used the tap to secure the blue wire to the tapped circuit.
IMG-7066.webp



After that, it was a matter of taping things back up
IMG-7071.jpg



Reassembling, and testing - everything was good to go!

After about 24h of testing - everything is great so far.. we'll see if it stays that way.

Hope this helps someone else out, and if anyone thinks there could be issues how I did it - please let me know your thoughts!
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chaps

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I need a key-on circuit to tap as well. In my case it is to signal a DC-DC charger for a LiFPO4 (lithium) battery used for camping. I need mine inside the cab, so this is a bit much. I thought it would be easy to find fuse in the BCM (left of steering column) fuse box that works. I have so far tried 28 (amplifier) 34 (Run/Start relay) and a couple others. So far all are “hot” with key off. Suggestions ?
 

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Engine bay fuse box #24 is a switched spare (high amp). Also you can use a fuse tap on inside #35 as a switched power for an acc.
 
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ebob9

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Yes, I never updated this thread - but I ended up following the BB guide and adding a pin to BCM3 in the drivers fuse panel, and just running through the firewall.

I ordered DU2Z-14474-DA for the pin/wire, and did it "as proper" based on the" 2021 Ranger BBLB R1" body builder guide at https://fordbbas.com/publications.

My guide above works fine, but I decided to swap to the "proper" route after other modifications.

1707503067173.webp
 


ozzy_Rowe

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I believe there is a better option.
So, I have an Australian Ford Everest 2022 (which is the SUV version of the Ranger and identical to the Ranger from the driver seat forward). The Australian Ford website ( https://www.ford.com.au/owners/vehicle-support/body-equipment-manuals/ ) has a "Body and Equipment Mounting Manual", which I believe everyone modifying their Ford Ranger should download and read before doing anything. Since it is for Australian Rangers, the manual is based on Right Hand drive versions, but you can do the mental reverse imaging we have to do when looking at photos of USA Rangers .....
On page 106 (see image below), it shows where there is a purpose installed 12v ignition wire fitted, so you dont need to piggy back wire anything. I hope this helps anyone trying to do this in future.
1744588931696-ez.webp
 

airline tech

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I believe there is a better option.
So, I have an Australian Ford Everest 2022 (which is the SUV version of the Ranger and identical to the Ranger from the driver seat forward). The Australian Ford website ( https://www.ford.com.au/owners/vehicle-support/body-equipment-manuals/ ) has a "Body and Equipment Mounting Manual", which I believe everyone modifying their Ford Ranger should download and read before doing anything. Since it is for Australian Rangers, the manual is based on Right Hand drive versions, but you can do the mental reverse imaging we have to do when looking at photos of USA Rangers .....
On page 106 (see image below), it shows where there is a purpose installed 12v ignition wire fitted, so you dont need to piggy back wire anything. I hope this helps anyone trying to do this in future.
1744588931696-ez.webp
The US version Ranger - does not have this - we have a similar tap buts it’s for trailer lighting.
So the need to fuse tap or add a relay powered device.
 

ozzy_Rowe

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Well isn't that a bit weird!
Why would Ford remove this for Left Hand drive models of the same car? I wonder if it is still located on the left foot well (i.e. your Drivers side)?
I have two labelled wires in this location on my car. The other one has a label "POS Light" and I am not sure what that is for yet.
 
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Fx4ranger2019Larait

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Yes, I never updated this thread - but I ended up following the BB guide and adding a pin to BCM3 in the drivers fuse panel, and just running through the firewall.

I ordered DU2Z-14474-DA for the pin/wire, and did it "as proper" based on the" 2021 Ranger BBLB R1" body builder guide at https://fordbbas.com/publications.

My guide above works fine, but I decided to swap to the "proper" route after other modifications.

1707503067173.webp
if you still have the truck or remember can you post some pictures or procedure you did to wire up sp9100? Thanks
 

Fx4ranger2019Larait

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if you still have the truck or remember can you post some pictures or procedure you did to wire up sp9100? Thanks
Bump on this thread…

Has any other member had experience installing a SDHQ SP-9100? If so how’d they install any help would be appreciated. Doesn’t look too hard but any tips would help thanks
 

airline tech

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It is mentioned in various threads - SP9100, but i have not seen or recall a step by step install if it.

But for switched power sources:

BJB - Fuse 19 or 24 (Fuse 24 will only be an option for the 2019 and some 2020's - as it was deleted for use - no contacts for connections (fuse)
Fuse 19 = PSCM and Fuse 24 (not used)

BCM - Fuse 35 or Fuse 37 - are good, switched power sources as they are not used, however the fused circuit remains intact.

Using a (Not Used) fuse is the best option - due to the (Fuse Tap) mounting orientation and if installed in the improper orientation it forces current flow across both fuses for your added circuit and with using the tap on a (not used) circuit eliminates that issue.

Example - Fuse 19 (BJB) you can only install the fuse tap (one way) and that install is actually the improper way to install it - it places both fuses - In Series vs separate power feeds for each circuit run - unfortunately this is just a reality of the fuse taps (new generation style) and the limitation of orientation comes from the (Relays) blocking proper routing.
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