ProudDadof3

Hi Everyone - Long time lurker. Read the FAQ on key fob but I am having a different problem. With a fresh battery both fobs work fine (alarm, trunk etc) but after a couple of weeks the LED is much dimmer and the car doesn't respond to the fob(s). Is it time to purchase new?

lowpue

It depends....Batteries are cheap. However, you may want to take it apart and blow the PCB with a little pressurized air in case you have some particle that is shorting something. Generally, I find that anytime I try to fix the fob like resoldering cracked solder joints, I screw it up.

Hurdigurdiman

FYI....I have had the same keys for the passed 7 years. Not needed batteries. Both keys are working just fine.

808Bill

Have you tested the old batteries?

JohnCA58

I had a problem with my Mercedes going thru a battery in the FOB every 2 weeks, finally figured out the Benz ECM was still active after shutting it down and sensing the FOB for up to an hour, and I left it too close to the car in the house, since i moved the FOB to the other side of the house I am still on the same battery over a year. I don't know if the 996 has the same capability.

crimony

I had this exact problem, tried twice to repair it and eventually was able to do so.

Removed the battery, then the PCB from the housing. Desoldered the battery holder to expose the ICs on the front of the board, then carefully touched up every solder joint on both sides of the board with a very fine tipped, temperature controlled soldering iron, under a microscope. I'm fortunate enough to have well equipped electronics labs (many, in fact) at my workplace.

The first time I only touched up the joints that I thought looked a bit dodgy, and this fixed the problem for a month or two, but it's now been 6 months since the second, more comprehensive attempt and it's been reliable up to this point, still on the same battery now.

zak996

I did the same thing Crimony did and that fixed my fob.