I have this problem for long time , the key doesn't work unless i am sticking it to the black part on the door handle and i cant find the solution or even the cause. I went to multiple garages and each of them said a different position for the device that recieves the signal from the key.So can anyone here tell me where the device which recieves the signal from the key is located ? , is it in the doors or above the rear windshield or where exactly?
Thanks in advance

 

Wooooooooooooooooooooooo slow down----first, have you confirmed that the key fob batteries are good!!

Second,the infrared receivers are in the door handles(the black part)

The system is complicated and if you don't have the diagnostic tools you will become a member of the "mumbo jumbo" club

 

First check the batteries in the key fob - they are not used for starting the engine, but they are used to transmit the RCL (remote central locking) signals. Also, check fuse #8 on the rear SAM (fuse panel in the trunk). If it's blown, replace it. If it keeps blowing, the ATA (anti-theft alarm siren) is bad and it needs to be replaced (or at least disconnected) before fuse 8 will work. Do you have another key and if so what does it do? If not, you really need a spare - yes they are expensive and can only be bought from the dealer, but they are cheaper than having a large four-wheeled unusable brick parked in the driveway. If none of this helps with the problem, then you may have a bad antenna amplifier. It's located the top of the rear windshield (assuming you have a coupe - it's under the dash on the cabriolet). If that's the problem, then learn to live with it as it's an expensive part (US$2K) and expensive labor to replace.

 

"It's located the top of the rear windshield (assuming you have a coupe - it's under the dash on the cabriolet). If that's the problem, then learn to live with it as it's an expensive part (US$2K) and expensive labor to replace."


Ouch!

 

I am already a member of the mumbo jumbo club 😂
But anyway do u know where the reciever is located? It in the doors for example?

 

The key batteries are fine . I will check fuse 8 👍🏻 . No i don't actually, when I bought it , it had one key and it gone bad so I bought a new one for about 193$ which idk is expensive or cheap to the prices in the us .( i live in a gulf country btw) and still the problem was there. I have been living with it for a year now cuz I expected that it will be very expensive . So its just one part called the antenna amplifyer and it is for 2000$ ? but isn't the same part where the radio transmitter and that stuff are included too ? ( i have the coupe) . And btw thanks for ur information , it's helpful

 

And Just out of curiosity, what could have damaged the antenna amplifyer? , I rarely see a car with a problem such as mine

 

Antenna amp failure is very common on the W203 C-Class. Two things happen, generally due to heat. One, the amp detaches from the glass so it no longer has contact with its antenna (that is embedded in the glass). Two, the Mylar ribbon cables that connect the circuits boards inside the antenna amp module delaminate from the heat. Since you live in the hot climate of the Gulf are, I am fairly certain this is the problem. When the amp simply detatches from the glass, RCL still works, but range is very short - like 20 feet from the car. When the amp totally fails, that when only the IR sensors on the door handles work.