Key fob not working to unlock car

[Ben Essex]

Hi Guys,

I'm new here, first mercedes I've ever owned and I love it. I bought the car from a dealer who had it for sale cheap with no warranty.

I took it for a drive and there is a couple of issues but the price was good.

What I didn't realize is they key fob does not lock/unlock the car.

The backup key that slides out obviously opens the car door and the fob will start the car. Before posting I've searched everywhere for answers. But nothing works. I'll put here what I've already tried, and see if anyone can help a new owner out!!

So, what I've done...

Replaced batteries
Replaced housing
Red LED lights up bright
Infrared is visible through camera phone
Fuse 8 is working, I've replaced anyway
Reset key fob via ignition and pressing of buttons
Radio signal is perfect

I only have one key, obviously a pain to lock and unlock in the rain!!

Any help is appreciated..

Thanks. Ben

 

[LostKiwi]

First things first... There is no such thing as 'No warranty'. Any retail sale (to a member of the public) is covered by the Consumer Act which gives you protection from dealers trying it on.
1.If you point the key IR at the door handle does it work?
2. Do all doors and boot lock and unlock together?
3. How do you know radio signal is good?

If the answer to 1 and 2 is yes it's possibly the amplifier (sorry - don't know where it is in your vehicle).

 

[Ben Essex]

On the receipt it said, not road worthy, spares and repairs. It does has mot and drives fine so that's why I bought it. Answer to your first question: No
Answer to number 2: Yes
Answer to 3: it's just clear and crisp.

 

[LostKiwi]

Ok so the issue isn't the amplifier as IR doesn't work (assuming we don't have 2 faults).
Time to get it on Star (dealer level diagnostic) to see what's going on.

Given you're probably from Essex given your username AMF or Welwyn Merx would probably be a good place to go (don't use a dealer unless you like writing blank cheques).

 

[onefortheroad]

Have you only 1 key ?

 

[Ben Essex]

Have you only 1 key ?

Yes, I only have one key unfortunately.

 

[Ben Essex]

Ok so the issue isn't the amplifier as IR doesn't work (assuming we don't have 2 faults).
Time to get it on Star (dealer level diagnostic) to see what's going on.

Given you're probably from Essex given your username AMF or Welwyn Merx would probably be a good place to go (don't use a dealer unless you like writing blank cheques).

I will search them and have a look. Thanks.

 

[Ben Essex]

Quick update, took it to a car key specialist, they tested the key and said the key is fine. It's a problem with the vehicle itself, the RF and IR are both not working. I'd understand if it was one or the other!! Any ideas? Thanks.