Can't find radio antenna

[MEZHH]

Hello everyone. I have a C230 1998 (W202). My radio is not working very well. When the signal is very strong it works, but usually I couldn't listen to FM radio. I want to change antenna, but I can't find it. Can someone help me please?

 

[Blobcat]

Hello and welcome

Rear window is common - part of what looks like the heating element. In all likelihood it is the antenna amp that has failed or the connection between the amp and rear glass element.

 

[MEZHH]

I don't know how to check connection between amp and rear glass. Can you help me to do that? I can send you some photos if you need.

 

[Blobcat]

Amp should be in the c-pillar at the top, check you’re getting power to it first. Just need a basic voltmeter

 

[brandwooddixon]

+1 for the amp - common problem.
On a saloon you will probably need to detach the door seal in order to remove the trim running up the C pillar next to the rear screen. I think that they're usually fitted on the nearside - inspection of the rear screen will confirm this as you'll probably be able to make out where the leads attach to the screen antenna.
If you've ever had the radio out, then its worth checking the continuity of the coaxial cable from the rear amp to the back of the radio. Use a paper clip at rear to short the ground and the centre wire then test at the head unit end. I've had a central wire break near the head unit that gave symptoms in the past similar to what you describe.

 

[M80]

On the later C class there is a pad that is pushed onto the rear screen. It becomes unsticky and falls off.

Removing the inside trim at the top might reveal that pad. I kept mine in place with UPVC spacers wedged in.