Add a key fob to your factory fob-less truck, under $20, no dealer visit

I wanted a remote door lock fob for my truck. It didn't come with them from the factory. After learning here on TW how easy it was to add cruise control and intermittent wipers, I was hoping adding fobs would be just as easy. Unfortunately, no luck...good programming instructions have been given here on TW a few times, including here...

https://www.tacomaworld.com/threads/how-do-i-disable-remove-a-key-fob.592075/#post-20051067

...but it doesn't work if your truck wasn't programmed for them from the factory.

I decided to add some anyway. My solution was to get a remote-operated relay setup. I used this SolidRemote receiver and remotes package:

$21 Solidremote 12V - 24V Secure Wireless RF Remote Control Relay Switch Universal 2-Channel Receiver with 2 Transmitters for Garage Door Openers, LED Lights etc (KIT-1)

https://www.amazon.com/gp/product/B01JGDV8UM

The SolidRemote receiver is just a pair of relays, set up to be operated by remote. The basic idea is to wire the relays into the vehicle in parallel with its existing door lock control switches. I'll show what I did to make this work on the locks, along a couple “extras” I included in my install, specifically on a 2nd gen. This should, in theory, work on any vehicle that already has power locks, but the chance of problems with it goes up the newer and more computer-controlled the vehicle is.

First, if all you want is something that locks and unlocks the doors, the SolidRemote kit includes everything you need. I wanted to get some feedback from the truck when I pushed a fob button to make sure it received the command, so I also wired the parking lights and horn into the system. This required buying two kits. They don't sell a receiver separately from the remotes, so I ended up with four remotes.

For all of the vehicle functions I messed with (lock, unlock, park lights, horn) the function is controlled by the body ECU based on input from switches. Each switch, when closed, shorts the corresponding ECU input to ground. Each Solidremote relay, then can be wired to ground on its COM side and spliced into the existing vehicle wiring between the switch and body ECU on its NO (normally open) side. Then, when the remote is pressed and the SolidRemote relay activated, the relay shorts that wire to ground and the body ECU responds exactly as it would had the factory switch been pressed. The first basic wiring diagram below is for a single receiver working only lock/unlock functions. Red is factory wiring, blue is what I added:

I set mine up so pushing one single remote button would do both lock and horn, and pushing a second remote button would do both unlock and parking lights. The wiring diagram for that looks like this:

I wired ~3 ft long lead wires to the terminals working on the bench. There are eight wiring terminals in each receiver. The two relay “NC” terminals don't get used here, and since one side of the power supply and both relay “COM” terminals are going to ground, I put jumper wires between those three. That left me with four lead wires per receiver: One for ground, one for +12V, and one for each of the two functions the receiver would control. With the first one finished, it looked like this:

While still on the bench I connected the power supply to a pair of 9V batteries in series to power them up for programming, and put an ohmmeter on the relay terminals for testing. They are easy to program following the included instructions. They can be set for latching or non-latching operation; for this use we want non-latching which is how they ship. (That mode is set by the three red DIP switches; they should all be off.) Programming is done by holding one or both of the two round black programming buttons just above the DIP switches. I set both relays in one unit to activate when either remote's “A” button was pressed, and both relays in the other unit to activate when either remote's “B” button was pressed.

Next up was figuring out where to mount them and where to wire them in. It looked to me that I could find everything I needed at the body ECU, which is just behind the lower dash trim at the driver's left knee, so I mounted them near there. I found some vacant space behind the dash, just at the top of and to the left of the clutch pedal. There was carpet up there, so I attached some self-adhesive Vecro hook strips to the back of the receivers and stuck them to the carpet. The picture is looking straight up at them, viewed from the clutch pedal. Folks with auto transmissions probably have more space here.

Removing the dash trim reveals the front face of the body ECU. Here, all coming from the “1C” connector shown, I found a violet wire that would control the parking lights, a green+red stripe wire that would control the horn, and a red wire that provided always-on +12V power. Use your favorite wire splicing method to hook up three of your leads here. Since access was easy I stripped a short section of insulation from each wire and soldered my leads to them. Once soldered (and tested) the joint was covered with liquid electrical tape.

Under the kick panel at the driver's feet, the “IA” connector is a convenient ground screw point, so I put both of my ground leads into a ring terminal and added it to the ground screw on that connector. This location is barely visible in my photo but is obvious when you look at it. The arrow points at the body of the connector; a metal tab with a ground screw attaching it to the wall. The photo is looking from the brake pedal straight left towards the kick panel.

Also at this location, there is an “IC3” connector that heads into the wiring tunnel to the door. My first attempt at this plan spliced my lock lead to a blue+white stripe wire and my unlock lead to a grey wire on this connector. These lead to the lock/unlock switch on the driver's door. Turned out this was a bad choice...in what I assume is an anti-theft feature, the “unlock” function doesn't work from the interior switches after the truck has been locked for a little while. The nearest alternative was the wire coming from the switch in the key cylinder on the driver's side, but that one would only unlock the driver's door on the first press. I wanted all four doors to unlock on a single press, so that meant splicing into the switch in the key cylinder on the passenger's side. I didn't get a picture of it, but the “IK3” connector's location is mirrored on the passenger's side from where the “IC3” connector is at on the driver's side, and “IK3” has a pink wire which takes care of the unlock function. So, I cut my unlock wire off of the grey wire and ran a new one over to the passenger's side to splice in there.

All done! At my final install, I left the lids removed from both of the receivers, which makes it possible to reprogram them without moving them. The relays in the receiver run for an advertised minimum of a half a second, or however long you hold the remote button. That didn't sound like much but the horn blast ended up being obnoxiously long, so I ended up programming the transmitter's “C” buttons to do just the locks without the horn for when I want it kept quiet. It hasn't been much of an issue anyway since I was already in the habit of locking the doors from the interior switch as I exit the truck.

I am left with an unused “D” button on my remotes. If or when I put cargo lights in the bed of my truck, I would probably get another receiver and use it to control them. It could possibly also be used as a garage door remote.

 

Hi 241240, I like your key fob idea but it sounds to hard for me. I wish you lived near me. I have a AC 4x4 2015 auto. I got the cruise control and wiper mod. but those a lot easer. I live in Mich.

 

DiggerRon, The hardest part was figuring out which factory wires to splice the new wires into. If you can find factory wiring diagrams specific to your year it'd give you a huge head start. Once I had that figured out for my 2009 the actual install only took about an hour.