well I have my 2000 C230 Kompressor that I just took the aftermarket stereo out and put the factory tape deck back in and for some reason I have hardly any sound on FM but when I switch it to AM or weatherband it is perfectly loud, like normal. Does anyone have an idea as to what this problem may be? The stock wires were never cut so I don't think it is a wire cross issue...Thank you for anyones help.

 

Did the after market head unit work correctly on FM?
If not then I believe the radio aerial / amp is faulty.
There are two aerials in the rear bumper which are feed into a single amp in the rear of the car before being fed down the coax lead to the head unit.
If the aftermarket head unit worked fineon FM then it is more likely the OE head unit that is wrong.
The ISO multiplug shouldn't give any problems if you haven't cut/removed the wires from it.
Try removing and reinserting the aerial lead into the back of the head unit. Sure its fully home?
Stuart

 

yes the aftermarket unit did work on FM I've tried several times to disconnect and reconnect the wiring it seems to be seated correctly. I am going to check the aeriel lead a bit closer and double check it all. Any other type of suggestions? thank you for your help.