KeyFob issues

Discussion in '2011+ Mustang GT 5.0L Tech' started by matholland618, Aug 16, 2019.

  1. matholland618

    matholland618 Junior Member

    Hey guys, another question.

    2012 Mustang GT Premium. Key that the car came with was an original key. Was having issues locking/unlocking. It only wanted to unlock twice from outside of the car, and I can never get it to lock with the keyfob unless I am inside of the car and hold it towards the roof.

    I replaced the battery thinking it was a weak battery, and that didn't change anything.

    I bought an Amazon key (I know not OEM, and I have always had good luck out them). Had the key cut and I programmed it with ford IDS. New key has the same exact issue.

    Where are the antenna's at on these things? Maybe the antenna is screwed up? Any other thoughts? Back when I bought a 2012 new, they always had decent range, so I know something is going on with it.
  2. matholland618

    matholland618 Junior Member

    Just an update.

    I found out that the antenna is either a part of the Smart Junction Box, or has an antenna ran through one of the plugs. If I point my keyfob at the box and get close, it works every time. I ended up pulling it out today and was going to try and pull it apart, but I didn't have any luck. It does seem to be working better than it did, but not as it should.

    I'm wondering if this antenna is internal to the smart junction box. If someone can clarify that for me, then it sounds like a replacement one will be in order.
  3. Iceman62

    Iceman62 Bullitt 6005

    Was the FOB battery you used brand new? I replaced one in my motorcycle FOB, but it was in saddlebag for over a year & it was dead, so I always start w/fresh batteries.

    Also, these Amazon FOBs can be hit/miss - OEM would be better...get fm dealer (IMO).
  4. matholland618

    matholland618 Junior Member

    The FOB that came with the car is OEM, I put a new energizer battery in it as I originally thought that the issues I was having was due to a weak battery. When I got my new Amazon FOB, I tried a new battery as well. I have the same issue with both FOB's whether it's the OEM one or the Amazon replacement. It's hit or miss. Usually, the unlock button works fine, but will only work once thus unlocking only the driver door. It doesn't seem to lock at all unless I'm pointing it right at the fuse box. I would say there is something up with that fuse box, but I don't have a way of verifying this with what info I know about them.

    I'd really like to get this fixed, as I was wanting to do the plug and play remote start that uses the factory FOB rather than going with a standalone that is much more difficult to install. It would be useless in its current state if I went that route.
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