Interior Ambient / Mood Lighting and Puddle Lights

[HendoMav]

Hi all, long time lurker, short-time Maverick Owner (2024 XLT Hybrid, bought August 6, 2024).

Got the usual mods done - bed cover, rubber floor mats, dash cam, etc. and now want to add some nice features.

1. Interior ambient/mood lighting. Love this on my wife's 2015 Mustang. Subtle lighting in the footwells. Would also add below the front seats, so the rear passengers get it, too.

2. Puddle lights. Exterior lighting at the doors (all 4) when you unlock the doors, turn off after you start the vehicle.

THIS WILL BE A LONGISH, EVOLVING THREAD! I'M DOING IT IN REAL-TIME AS I'M WORKING THROUGH THE DESIGN/IMPLEMENTATION!

Now, analyzing the way the Maverick behaves, and the different model options/features, I've narrowed it down. The dome light comes on (all models) when you unlock the vehicle, or open the door. The dome light goes off when you start the vehicle (or about 60 seconds has elapsed). So, it seems to me, that puddle lights should track the dome light. When you unlock the truck, the dome lights come on - so should the puddle lights, to illuminate around the truck. And then when you start the truck (or after 60 seconds of closing the last open door - how slow are you, after all?) the dome light goes off - so should the puddle lights.

So - for puddle lights, I'll track the operation of the dome lights. Done.

Ambient/mood lighting? Well, in the Mustang, they turn on when it's dark outside. When you unlock the vehicle, the mood lights come on, and stay on (if it's dark outside). I'd like that, too. So when you open the door you can see the floor, etc. So - dome light! We want that same behavior. HOWEVER, we have the added requirement of staying on if it's dark!

Now, the XL and the XLT do NOT have dedicated daytime running lights; they use the low beams instead. The Lariat, however, does have DRLs. In automatic mode, the Lariat's low beams come on when it starts to get dark, which is the behavior we want.

So - solution for mood lighting that works for all models: turn on when the dome light turns on, AND stay on if the low beams are on (meaning it's either dark enough to have them - Lariat - or it's maybe dark - XL/XLT).

Summary so far:

- Puddle lights track the dome light
- Ambient/mood lighting tracks dome light and also stay on if the low beams are on

So, what I need is a way to do that. Now, I could tie into circuits directly and hope - but puddle lights (the ones I'm eyeing) pull a few amps, as does mood lighting. Will that overload the CANBUS system which monitors current draw and flags errors based upon overload/underload conditions? Who knows. But, being a long-time engineer, I'll make my own drive circuit...

Next post gets into some electrical theory, so skip if you're not interested in it.

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[HendoMav]

ELECTRICAL THEORY

What I want, is a solid state switch. Effectively a switch which can carry a pretty beefy load, without straining the existing signals I want to use. An electrically controlled switch. Lots of people would say "just use a relay", but relays can pull significant current (50+ mA), equivalent to the lights/load on that line. I'd rather not. Additionally, relays can stick - not good!

For inputs, a quick examination of the BCM wiring shows me that the dome light and low beams both come from the BCM - success! I have found my inputs. In particular, it seems to me that the rear dome light is the yellow-with-green-stripe wire, and the low beams are the blue-with-green-stripe wire. So, we have found the wires to use as inputs.

Now, how to switch? Well, we use some transistors. Why, you ask? Well first, I'm an engineer (electrical) and transistors are cool. Second, they are EXTREMELY low current draw, so tapping a transistor load to either of the BCM lines will pull a few tens of microamps of current - not enough to be reliably detectable, let alone set off a CANBUS "blown" warning.

This is where it gets fun... We're gonna use bipolar junction transistors (BJTs) AND field effect transistors (FETs)! For very specific reasons, which will come up, later.

A BJT essentially is a current controlled switch. You put a small voltage from the base (the on/off input) to the emitter (output) and it will let a LOT of current flow from the collector (input) to the emitter. So put a volt or so into the base relative to the emitter, and you get hundreds of milliamps - or even amps - sucked from the collector to the emitter. So let's use that!

Now, a FET is kind of the same thing, but we give the parts different names: base becomes gate, collector becomes drain, emitter becomes source. Because consistency makes it easy for others to understand how easy our job is.

Why use a BJT or a FET? BJTs are pretty simple devices, robust, and cheap and easy. FETs can move a lot more current and are faster for switching (ideal for what we need) and more efficient (less dissipated heat). So I ended up designing a circuit that uses the input signal to switch a BJT, then the output of the BJT to switch the FET. This is the basic configuration:

This is the basic circuit I plan to use (I'll attach the TINA - TI Spice program - file at the end of the thread, with all the Gerbers, etc). The signal is SIG - turns on from 0 to BATT after a second. V1 is the battery, it's 14 volts. T5 is a BJT; T6 is a FET. The numbers next to them are part numbers (if anyone wants to know why I chose the actual components I ended up using, I can expand on that). The zigzags are resistors. R9 is my load (6 Ohms - about 2.3A current), and the two big circled Vs are volt meters.
Here's what happens when you connect it up, and then "turn on" the signal:

Yellow is the signal. Red is the "MID" voltage. Green is the "OUT" voltage. So we see things work! The output is low until the signal shows up. Then it turns on! Perfect

So we use this design, with the chosen FETs, and when the dome light comes on, the FET to power the puddle lights will kick on - and all is happy, because we're tapping microamps from the BCM line, so nothing will appear wrong to the CANBUS system.

A few extra components, to sum input signals (diodes) for the mood lighting, the same basic circuit, and we're set!

Input of the dome light goes to Q3, to turn on the puddle lights. Input of the dome light AND the low beams are summed via the diodes, so that if EITHER goes high, the signal to Q1 is high and we turn on the mood lighting.

Success with design! Now to lay it out, build, and test!

 

[HendoMav]

So, the schematic is done. A quick board layout is in order. This means choosing connectors and such. I chose two different connectors to use:

- RJ45 (Ethernet) for wiring from the BCM to behind the rear seat
- Pluggable terminal block for all else

Why RJ45 and CAT5 cables? Easy - small overall diameter for 8 wires, reliable connector, dirt cheap. I can plug one end into my board, run the wire easily under the plastic trim below each door, and to the BCM where I can cut the cable and use the correct color wires to connect as needed!

So I laid out the PCB, and this is what I have:

Two connectors along the bottom side, all components (through hole - easier for anyone to solder) also there. Double sided board; traces on top, solid ground plane on the bottom. A couple of screw holes as well, so I can mount it in a small 3D printed box (details coming soon). Boards ordered, parts ordered (full Digikey BOM available, too), and then to stuff!

 

[Nemo]

There is also the bed light, believe it is driven by pin 6 from the BCM connector. Was planning to drive my puddle lights directly from it, with them being LED (planning to use the ones from a newer F150 or the cheaper 2024 Ranger ones) with a small load. Bed lights already being standard bulbs. Plus, you would be able to switch on the puddle lights with the bed light switch, independent of the dome light.

 

[HendoMav]

There is also the bed light, believe it is driven by pin 6 from the BCM connector. Was planning to drive my puddle lights directly from it, with them being LED (planning to use the ones from a newer F150 or the cheaper 2024 Ranger ones) with a small load. Bed lights already being standard bulbs. Plus, you would be able to switch on the puddle lights with the bed light switch, independent of the dome light.

Yeah, that could work too! I can mod the circuit to have a remote "in" for the puddle lights, so a switch you can toggle if needed. I wanted to avoid adding any loads to the existing wiring, because before you know it - you've got 17 things hanging off a single circuit and start going 'what have I done?' Isolating it to a separate board - which will be fused off a distribution block fed from the battery - will solve that.

I can tweak it pretty quick to add a remote-override for the puddle lights, though... Updated schematic:

On the 6 pin plug connector, pin 5 is an AUX input for turning the puddle lights on. Take it high to any BATT voltage source and it'll kick on the puddle lights. Ground the puddle lights to pin 6.

Board layout done:

It's tiny! 60mm wide, 32mm long (2.375" x 1.25"). I plan to 3D print a 2mm wall-thickness enclosure for it, with mounting tabs. So the overall outside dimension will be 64mm wide, 36mm deep, and the height will be about 20mm, because the FETS (Q2 and Q4) are larger packages and stand upright inside the box. 2.5" x 1.5" x 0.75". That's small enough...

Note that I am using SEPARATE power sources for mood lighting and puddle lights - you wire power to each of those circuits, so you can fuse them independently! If you blow the puddle lights, mood lighting still works, and vice versa.

 

[HendoMav]

OK, a few updates:

1. Move to two 6 pin headers - one for inputs (power, ground, dome light, low beams, puddle light constant, underseat switch) and one for outputs (ambient lights, puddle lights, underseat lights).

2. Added a USB type A output, good for 2 amps. It is ONLY on if the mood lighting or puddle lights are on. Always good to have extra USB ports around, eh? And if you use the puddle remote switch, it's always on.

3. Added an underseat circuit! Plan to use a small magnetic reed switch to turn it on and off. Put the switch in the plastic tray under the rear seat, and the magnet on the bottom of the seat. lift the seat, and the lights will come on. Independent of any other lights.

4. Added an ATM (mini AT size) fuse on the side. You can run battery right to this, and it has its own fuse internal for protection. I plan to use a 7.5A fuse for my build: 2.3A for the puddle lights, 1.5A for the ambient lighting, 1A for under seat lighting, and 2A left for the USB. That is plenty for my needs, but you could bump up if you want; the FETs for the lighting are rated to 20A, but the USB still tops out around 2 - 2.5A.

So, this should provide ambient lighting, puddle lights, USB 5V @ 2A (type A), and under rear seat lighting. All on a small 4" x 2" board.

Schematic attached! PCB layout completed as well, but won't bore you with that.

Anyone want any other functionality for interior/convenience lighting? If not - I'll get some boards made,stuff them up and see how it works!

 

[14mikey14]

All of this is...AMAZING! Some of it is over my head but thoroughly enjoyed reading through it. You made it very easy to understand your thought process and why you chose to do what you did. Very detailed yet not pedantic. I would be interested in purchasing this if/when you have it ready. The only thing that I would want changed is to have a USB C port instead of a USB A port. But that is not a deal breaker.

 

[HendoMav]

All of this is...AMAZING! Some of it is over my head but thoroughly enjoyed reading through it. You made it very easy to understand your thought process and why you chose to do what you did. Very detailed yet not pedantic. I would be interested in purchasing this if/when you have it ready. The only thing that I would want changed is to have a USB C port instead of a USB A port. But that is not a deal breaker.

You're welcome! I'm doing this for me, but would love to add features that others find helpful.

I'd prefer type C as well, but the type A is a lot easier to solder, and allows for more flexibility. Like I noticed with many automotive accessories, they're using a built-in type A connector (like on the ambient lighting module I selected - I won't use it, but I see it has it). And there are type A to type C adapters available, so...

My intent is to release the schematic, Gerbers, bill of materials, and 3D files (for the enclosure) so anyone can make them. You can buy the parts, or get someone else to make them.

When I make the demo PCBs, there's typically a minimum of 5 to 10 boards needed. So, if you're handy with a soldering iron (these are all through-hole parts with big spacings), it should be easy for anyone to stuff. I can send you a blank board, and with the bill of materials, it'll take 2-4 days to get all the parts from Digikey!

 

[inline_five]

You're welcome! I'm doing this for me, but would love to add features that others find helpful.

I'd prefer type C as well, but the type A is a lot easier to solder, and allows for more flexibility. Like I noticed with many automotive accessories, they're using a built-in type A connector (like on the ambient lighting module I selected - I won't use it, but I see it has it). And there are type A to type C adapters available, so...

My intent is to release the schematic, Gerbers, bill of materials, and 3D files (for the enclosure) so anyone can make them. You can buy the parts, or get someone else to make them.

When I make the demo PCBs, there's typically a minimum of 5 to 10 boards needed. So, if you're handy with a soldering iron (these are all through-hole parts with big spacings), it should be easy for anyone to stuff. I can send you a blank board, and with the bill of materials, it'll take 2-4 days to get all the parts from Digikey!

This is all way above my paygrade but I recently did something super simple here:

Expandable interior ambient lighting using Ada 1626 LEDs - DIY install writeup

I really like your solution because it does a bunch of different things that I wish mine did which is just "on" 100% of the time.

FWIW the five LEDs I'm using draw around 20-30 ma combined IIRC. They are extremely low power. Using something similar for puddle lights as well would be closer to 20-25 ma per LED at higher brightness levels (so about 100 ma combined for them).

I'm going to do a second iteration and use a PWM to control the LED brightness but yours is next level. I've enjoyed reading it, and can't wait to see it work. The EE side of it is fascinating to read, at this point I'm just happy I can solder a resistor to a board.

I will say I am extremely happy with the lighting I added. It looks higher end.

 

[HendoMav]

This is all way above my paygrade but I recently did something super simple here:

Expandable interior ambient lighting using Ada 1626 LEDs - DIY install writeup

I really like your solution because it does a bunch of different things that I wish mine did which is just "on" 100% of the time.

FWIW the five LEDs I'm using draw around 20-30 ma combined IIRC. They are extremely low power. Using something similar for puddle lights as well would be closer to 20-25 ma per LED at higher brightness levels (so about 100 ma combined for them).

I'm going to do a second iteration and use a PWM to control the LED brightness but yours is next level. I've enjoyed reading it, and can't wait to see it work. The EE side of it is fascinating to read, at this point I'm just happy I can solder a resistor to a board.

I will say I am extremely happy with the lighting I added. It looks higher end.

Yeah, I like your solution - simple and easy!

I wanted to add a bit more "flexibility". I bought a smart accent light kit (Amazon ASIN B0CJTYSPKH) and it works really well. Can adjust the color and brightness. Have it temporarily wired to a 12VDC to 5VDC adapter, via fuse 3 in the BCM. Dialed in a color that my colorimeter says is a 97% match with the Ford teal. And it's not too bright for me! It pulls about 1.2A running.

For the puddle lights, I wanted something really rugged and also adjustable, so I can tweak the color/brightness as desired. So I bought a rock light kit (Amazon ASIN B01MG5UXV4) and it is RUGGED. IP67, tough light cases, and REALLY bright and adjustable colors. Pulls 2.2A with all 4 lights running.

I'll document as I start assembly, design the 3D enclosure (I'll release STEP and STL files - I hate it when people just give you the STL), and do the actual install. Step by step!

 

[HendoMav]

So, PCB is laid out, I've slept on it for a week, I and I can't think of any changes I want. Sure, I could put filter caps and protection diodes all around, but - nah. Build it and it's done. Performance won't be better.

So - here's the rest, it's time to order boards!

On annotated layout, I circled the USB power supply in white.

The USB type A connector in green.

The input connector and diode logic (wired OR gates) are circled in pink.

The output and output FETs and drivers are in cyan.

Oh, the ZIP file contains the Gerber (PCB layout artwork) files, the bill of materials, the schematic, and the TINA Spice model for the basic building block used (download TINA here: https://www.ti.com/tool/TINA-TI).

Now - off to order boards and a few sets of components I don't already have! Then to start some mechanicals - 3D printed, top and bottom, lip and rebate to align, and 3 screws to keep it together!

 

[HendoMav]

OK, I've finished up the mechanicals. It's 2 pieces, an upper and a lower housing. Held together with three 3mm x 30mm long plastic screws (available from www.mcmaster.com). I plan to 3D print the two halves, black on the bottom and medium blue on the top (to match my truck), with my FDM printer (fine finish of the SLA isn't needed).

The full mechanicals are attached - a complete STEP file with the housing, screws, connectors, and a sample of each of the largest components, in their place, to make sure we have clearance (I didn't add the resistors, small transistors, etc - they'll clear fine). There is also a 3D PDF inside, you can click and spin the assembly, hide parts, etc.

I'll upload the STL files elsewhere - they're too big for here.

Hopefully assembling the week after Christmas!

 

[Toddman45]

This is the first Ford I've had that doesn't have puddle lights on the exterior rear view mirrors. My 12 F-150 had them 16 f150 16 Ford fusion and 19 explorer as well. The 24 Maverick is the first one not to have puddle lights sadly.

 

[HendoMav]

This is the first Ford I've had that doesn't have puddle lights on the exterior rear view mirrors. My 12 F-150 had them 16 f150 16 Ford fusion and 19 explorer as well. The 24 Maverick is the first one not to have puddle lights sadly.

Yeah, they cut a lot of corners to get the price down low.

I looked at adding them to the mirrors, it would be possible to do so with a single wire. But I wanted to put them next to the rail underneath the doors, so if I move the doors - I don't move my puddle light, too!

 

[Toddman45]

Yeah, they cut a lot of corners to get the price down low.

I looked at adding them to the mirrors, it would be possible to do so with a single wire. But I wanted to put them next to the rail underneath the doors, so if I move the doors - I don't move my puddle light, too!

I always used the DriveBright.com puddle lights for the mirrors.

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