Is there a member who is fluent with car audio electronics? I'm having a problem with my radio, static and poor AM-FM reception. I know the radio is good because I can plug-in an antenna into the back of it and it works. The problem is trying to determine if the problem lies inside the antenna cable as it journies to the trunk. How can I use a multimeter to determine if there is a break along the way or if my powered antenna booster/amplifier is defective. The last item is not standard issue. Any tips for me? I would like to test the cable to see if there is resistance or no flow if you will and not sure how to do this. Reasoning, if the cable is OK than the antenna amp has gone bad, Thanks Steve

The antenna cable is coaxial cable. One conductor down the center surrounded by a shield.

You can check this with a standard multimeter. You might need to extend the multimeter leads with a piece of wire and a helper would be very beneficial.

Center to center = continuity
center to outer = no continuity
outer to outer = continuity
outer to car body = no continuity (make sure both ends are unplugged first)

You might have to play follow the cable and see if it has gotten pinched or broken somewhere along the way.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Thanks Jay Bob, Thank You for explaining how to check the antenna cable. The problem is my am-fm reception, it is very poor, static on the AM...and FM real poor. The antenna has an amplifier mounted on the underside of the trunk lid So while I'm trying to determine if the cable has a "break" in it using the method you suggested, could it be possible that my reception issues are due to a lack of power (12V) to the antenna amp?, any thoughts? My thinking is no juice... no reception? I connected a regular, old-time antenna to the back of the radio, and the reception was good on both am and fm. The problem is the antenna cable and amp are located in the back of the convertible. To replace cable means tearing up the inside of the car upholstery, moving trans tunnel, seats, carpeting, etc... The amplifier is expensive so I'm reluctant to throw lots of money towards an expensive part without knowing that the amp is defective.

Thanks, Steve