Greg Lab

My key Fob will not lock/unlock doors. I have replaced the Fob battery, still no luck. What's next, take it to the dealer?

NEK

Check the contacts to make sure they are contacting (pinching the battery). I had to adjust mine a few weeks ago.

mike cap

Does the red LED light up when activated?

techman1

Attended a convention wearing a nametag held on with magnets. After the event I put it in my pocket with my keys. The remote was dead that evening. Luckily the honda!

TMc993

+1 Has happened to me more than once.

Greg Lab

I cleaned the contacts and pinched the battery a little tighter, problem solved, thanks!
Anybody know where the sensor is in the car? It seems to work better about 3 ft away from car... I always thought it was near the door handle, but maybe not.

TMc993

I believe it is under the seat with all the immobilizer/alarm/central locking system gizmos. The range on my fob is around 4-6 feet, sometimes more and sometimes less. I believe that is pretty typical for these cars.

nine9six

...And I believe Terry's right in all respects...

Spokes

Sick, but if you hold the key fob next to your brain it will operate twice the distance away from the car - I wonder how many of you will try that! Courtesy of Jeremy Clarkson !

Kika

Any RF transmitter needs an antenna, the more efficient (gain) that an antenna has, the stronger the signal it will transmit. Holding an alarm transmitter, or even a cell phone, when it is transmitting a large file, against your body helps, as your body will help transmit the signal. Remember how much of your body is water and water is a great electrical transmitter.

There are some really cool tunable HF antennas that the Navy uses with pressurized salt water. The wavelength (frequency) of the antenna is tuned by changing the pressure, thus varying the length of the antenna. They use them at sea, saves a ton of space vice having an antenna farm on top of a ship.

SonnyT

Good to know the body trick, and thanks for explaining why, kika. I've had the remote battery on the verge of dying and leaving me locked out. I walked all around the car clicking and allowing the batt a few minutes after each attempt to recoup. It actually opened when I went to the passenger side towards the front of the door

Greg Lab

That's interesting about the passenger side front fender being sensitive spot to hit the remote. After I got the Fob working by the driver door, I walked around to the front passenger fender, doing something else, bent down with key Fob in pocket, and it activated it accidentally.... Keep that in mind when you have a weak battery in the Fob. Maybe an easier hit of the actuator underneath driver's seat...

Kika

I believe the DME brain is under the passenger seat, not sure if that is where the immobilized receiver is, but assuming it is, then reduced range to that location will help. Holding the transmitter against the door or A-pillar should also help.

Honestly, the BEST thing for all of us is to simply put a new battery in the fob every year, they aren't that expensive.

pp000830

Begs the question; If one attaches a longer antenna wire to the receiver in the car will the car open from greater distances like my VW does? How about moving the antenna outside the car body for example under the edge of the windshield trim rubber? Would be really nice when opening the car for my wife or even locking the car as I walk away from it.

Kika

Basic radio theory is that signal strength diminishes as a function of range, as well as other factors, so if you can bring the transmitter and receiver closer together, the communication link between them requires less signal strength to close.

There is an optimum antenna length for both transmission and reception as well, which is related to the wavelength of the transmitting frequency, so just putting a super long antenna is not necessarily the best solution either.

One of my first car alarms ( back in the 80s) that used an RF transmitter, had a receiver with a suction cup that was mounted on the inside of the windshield, you had to put the transmitter against the windshield right next to it to arm and disarm it. Later I had an Alpine alarm that I could arm and disarm from well over 100 ft away.

For all practical purposes, 10-20 feet is usually more than enough.

Certainly as activation range starts to decrease, that is a good sign that you battery is weakening, although as mostly of us stick our keys into our pockets, a bunch of lint inside the transmitter isn't good either, so keeping the electrical contacts clean is a good idea too.

In fact, I have saved hundreds of dollars in repairs and replacement by cleaning the electrical components on our dryer, talk about a haven for lint!!!!