[Stevebanks]

I’m brand new to The Mercedes world and forum. I just bought a 2003 SL500 with 40K miles. The central locks work, but the key fob will not lock/unlock the doors or open the trunk.
Over 3 days the fob locked the car 3 times and unlocked it once, and the rest of the time:nothing. I did change the battery in the single remote key I got with the car.

 

[mbw209]

Go in the fuse box behind the passenger front seat and replace fuse # 58.

 

[Stevebanks]

Go in the fuse box behind the passenger front seat and replace fuse # 58.

Thanks, I checked this and it appears to be good. If this was bad, would it lock/unlock randomly as it has 2-3 times? 50 other times it has not worked.

 

[mbw209]

Does the ignition recognize the key?

 

[Stevebanks]

Does the ignition recognize the key?

Yes, the ignition recognizes the key and it starts right up. Central lock works every time. Key fob has locked the doors three times, has unlocked them once (used the Hard key the other 2 times with alarm going off) and the trunk has not opened with the fob.

 

[mbw209]

Do you have a spare key to assess whether it’s the key or an electrical component?

 

[Stevebanks]

Do you have a spare key to assess whether it’s the key or an electrical component?

Thanks for sticking with me. I’m going to buy a second key from the dealer and rule that out next. I want a second key anyway. I’ll probably go quiet until I get a new key.

 

[mbw209]

Good luck. Let us all know if that worked so anyone having this issue will know what they need to do

 

[sp.0402]

I have the exact same symptoms. Been search for a while and haven’t found anything. You’re the only person that have the same symptoms so far. I was hoping I find something out before resorting to a new key. And even then I’m leaning towards it not working .


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[mbw209]

Can also try this before buying a key

 

[sp.0402]

So I finally jump the gun and got a new key made by a local auto locksmith for 200$. New keys remote lock unlock. Alarm, window up/down is now working but via infrared only about a feet away pointing directly at it.

Not sure how far the range of these are supposed to be. If anyone can share that would be great.


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[mbw209]

Sounds like your key was the problem. Glad you got it working again. As far as the remote window up/down function mine works as far as about 5 feet away (If I’m lucky) only while pointing the key at the drivers door handle

 

[sp.0402]

Thanks for that. I didn’t make many attempts so I’ll have to try it again. Also. Doesn’t our car have a radio controlled feature too ? So the remote can work farther without the infrared?


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[Gary Knox]

Try putting new batteries in the original key. Check YouTube for a quick and easy way to remove/install batteries (it takes two, I think they are designated 2020 - not the year, but the battery type). Did this to my 'non functioning for lock/unlock key about 3 weeks ago, and now it works perfectly).

Gary