Over the past month my keyless doorlock system has beem gradually getting weaker and weaker and I had to be closer and closer to the car to get it to work.....seemed obvioous and easy fix...just put new batteries in the key fob....but put two new ones in today and it doesn't work any better.

It only works if I'm standing very close to the car and on the drivers side.

Any help as to what's wrong.

Warren C.

What year & model car Warren??

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1999 E300D (W210) but with a replacement remote.....the fancy chrome/black type.

Warren C.

I have the same issue with my 1996 E320, remote range about 3, 4 feet. New battery no help.

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Did some more tests today......determined that the RF is not working at all....it's only the IR function that works with the receiver in the door handle.

That's why it only works at close range....and line of sight to the door handle.

So now what....

How to check the transmitter in the key fob ????

How to check the reciever in the car ????

Warren C.

How old is the key & do you have more than 1??

That isn't (checking RF siganl) easy even at dealer on that model!

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MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

The key is about 1 1/2 yrs old.

WC

But it is on my 95 Lincoln Town Car. Anyway, I heard on "Click and Clack" one Saturday morning, that if your remote doesn't work real well, try aiming it at your skull instead of anyplace else. Seems that the shape of the skull magnifies the signal significantly. It really does the job on the Lincoln, it might work on your Benz also.

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....and does it "do the job" on your brain also ??? i.e. after 1000 clicks your brain turns to mush.

LOL.....

Warren C.

That's actually quite true. The skull adds a good 3-6 db of gain to the signal. I used to have a Chevy that I could unlock from 50 feet away using that trick.


Testing the remote is easy. Just get a broadband RF preamplifier that works in the frequency range of the remote. Put a makeshift antenna on it. Then, couple the output of that RF preamp to your handy dandy RF spectrum analyzer. You should see a nice peak in the frequency range of your remote when you activate it. If you don't, looks like the remote's dead.

What, you're not a T.V. engineer too?


Okay.....


First, just open it up (if possible) and check for anything obvious such as broken solder joints.


I would also check to make sure your car hasn't "forgotten" the keychain. There is usually a way to program the car to use the remote, and it involves the car "learning" the signal from the remote. Check that angle out.


Good luck!

-tp

A way to test the IR remote (or any IR remote for that matter) is to use the LCD viewfinder on your digital camera or video camera. The sensors inside the camera can "see" IR activity from a remote and project that activity in the display. Obviously, this only works with IR devices, not RF.

It helped me when I was troubleshooting the remote for my 97 e300d.

.....Dan

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