Introduction: Ford Key Fob Antenna
Due to ford being completely cheap or negligent my doors continue to freeze closed or open. 3 unsuccessful trips to the dealer for work later. I decided to take steps to lessen my frustration during this time in between now and when they come up with an actual fix for the problem. This is a lease vehicle, I do not have an intention to buy, spending extra money to put more parts into it is not an option.
I can remote start my truck at my home, but where I park at work it was just out of range. So this is how I get my factory remote starter to reach a measured distance of 1098.24 feet! This is an easy mod with very little cost. I hope this helps other people because I was unable to find a solution on the internet that didn’t involve new equipment.
(Mine is a 2018) Ford switch blade key fob
Short length of phone wire
Small screw driver
Knife or file
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Step 1: Can It Be Done?
Everything I could find online basically tells me stick my key fob in my mouth and somehow it will reach farther. That is not what I want to do every time I want to start my truck. So first I find out what frequency the key fob operates on. And then I look up how to build an antenna with that frequency. Next Disassemble key fob And look into will that antenna fit in my fob. I found a pocket after measuring it with a caliper and what do you know there is a spot with the exact measurements outlined on the website for building a 315 MHz antenna. looking at the circuit board I see 2 holes in the antenna band that are not being used. looking promising so far.
Step 2: Make Stuff
With common phone line wire, strip the insulation off a piece approximately 12 inches long. Wrap 16 turns around a small diameter screwdriver leaving a tail on one side. I used super glue to hold the wire tight together. Slide off the screwdriver and dry fit it in the space of the key fob. Identify the two small holes in the circuit board that you will need to pass the wire through to solder it. You can see the outline on the circuitboard where the antenna is. There are two unused holes at the base of the antenna. See pictures. With a file or knife narrow the diameter of the wire so it may pass through the hole on the circuitboard. Once you’ve done that pass the wire through the board with the antenna seated in the plastic housing to get all the spacing correct. I placed a small piece of double sided mounting tape on the backside of the circuitboard to hold the antenna once everything was fit together. After Everything is dry fit then solder your connection to the board trimming off excess wire. Make sure the wire only touches the board at the point where you soldered it to make sure there is no electrical short at any other point.
Step 3: Reassembly and Testing.
After I reassembled my key fob I put fresh batteries in both mod and non modified remotes. Then I took a walk through my neighborhood as I got further from my home I continue to test both key fobs. Once I reach the point that the OEM fob no longer started the vehicle I switched to the modified key fob and continue to walk until it no longer started the vehicle. Marking the spot and measured out on Google Maps for distance. ..114 (601.92 ft) miles the OEM stopped working. The new antenna remote stopped at .208 mi (1098.24 ft) total increase of 497 ft! Worth while improvement. I hope this helps other Ford owners out there as it seems to be an apparent issue both with the doors freezing and the key fobs having short range.
Anomalies to note: My wife reported that sometimes the vehicle started even though the key fob responded with a red light indicating it did not start with both key fobs. However the key fob with the additional antenna reported the vehicle successfully started (green light) much further away than the unmodified key fob.
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