Curious how the FOB works
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Road Captain
Joined: Jul 2008
Posts: 613
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From: East Alton, IL
Curious how the FOB works
Not a big deal. Winter boredom set in and I started to wonder just how does the security system work. I went to ride my 10 FLHTK the other day and the security wouldn't let it start. I pulled the fob battery and checked voltage, knowing it was less than a year old, and got full 3.02 volts. So I rubbed the battery on my jeans and put it back in and sure enough it let me ride all day.
That got me wondering if anyone knows how the system works. Does the FOB send out a signal every once in a while or does the bike send out a signal periodically looking for the response from the FOB? So in other words the FOB just listens most of the time and when it hears a request, from the bike, it sends a signal that says I'm here.
The latter scenario seems to make more sense from battery longevity stand point.
That got me wondering if anyone knows how the system works. Does the FOB send out a signal every once in a while or does the bike send out a signal periodically looking for the response from the FOB? So in other words the FOB just listens most of the time and when it hears a request, from the bike, it sends a signal that says I'm here.
The latter scenario seems to make more sense from battery longevity stand point.
Outstanding HDF Member
Joined: Jan 2011
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From: Western Illinois, land of bad roads, and corrupt politicians
It's my understanding that the bike sends a signal to the FOB when the bike is moved, or the ignition is turned on. The FOB then responds, and the security system disarms.
If it was the other way around, your FOB battery wouldn't last as long. Receivers don't use as much power as transmitters.
If it was the other way around, your FOB battery wouldn't last as long. Receivers don't use as much power as transmitters.
Tourer
Joined: Jan 2014
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From: New Brunswick Canada
The way I understood it to be is that the bike is always monitoring for that fob to come within range. The fob is always powered I believe, that being said I have had it happen to me where the bike doesn't pick it up right away so I could be wrong on this.....
Road Warrior
Joined: Jun 2014
Posts: 1,357
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From: Michigan
Yes the bike will not pick it up at times, especially if you are close to something like an IR switch, such as the entry doors to some stores.
While this hasn't happened to me as of yet I have read where some have had actually roll there bikes away from the building in order to eliminate the interference.
I believe the FOB actually acts like an antenna, which is tuned to a specific frequency, when close enough to the bike's emitter the fob completes the security circuit.
While this hasn't happened to me as of yet I have read where some have had actually roll there bikes away from the building in order to eliminate the interference.
I believe the FOB actually acts like an antenna, which is tuned to a specific frequency, when close enough to the bike's emitter the fob completes the security circuit.
Stellar HDF Member
Joined: Sep 2013
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From: USA
From this section of the wiring diagram (2008 Touring) it appears that the HFSM transmits to and receives a signal from the fob. At least that's my guess.
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Seasoned HDF Member
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From: Somewhere on the Bourbon trail
Originally Posted by rusty289
The way I understood it to be is that the bike is always monitoring for that fob to come within range.
Originally Posted by TheGrandPoohBah
The fob is a "Proximity Emitter".
Someone can chime in on that.
Last edited by RKZen; Feb 11, 2016 at 01:54 PM. Reason: subtracted some stuff
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