The ham radio in my 2015 C300 4MATIC is currently connected to power via the rear center console cigarette plug but there seems to be a voltage problem that causes the radio to turn off randomly even in receive mode and it will not turn on again for hours. I could wire it directly to the battery but I don't want to hassle with going through the firewall. So I thought I would connect it to one of the fuse boxes either in the car or the trunk using a fuse tap. Does anyone know which fuse I should tap to provide the power source? The fuses in the radio power cable are 10A fuses.

There are two 15A fuses in the trunk fuse box--one for the rear center console 12V socket and one for the front cigarette lighter. Might I try tapping into either of these fuses directly?

Thanks for any suggestions.

 

I'd suggest you put it in something that's not being used actually if you'll put a constant strain on it, something like fuses 400-402 which is used for AdBlue system which won't be present on your car or 445 which is used for the rear socket on S205.
https://fuse-box.info/mercedes-benz/...uses-and-relay

 

Thanks, I appreciate the reply. I wonder if might make sense then to connect it to one of the empty fuse slots that's listed as "spare." Seems like that wouldn't necessarily affect anything else in the car (I would think).

 

Yes, that should be OK as long as those fuses turn on and off when you want them to.

 

I connected mine to the main power-in to the trunk fuse box. It can handle the load and is always hot, then used an inline fuse for the radio. My radio has a fair amount of draw if transmitting full power and I didn't want it on a switched fuse, so I can use the radio without turning on the ignition. My radio chassis is mounted in the trunk and I use a remote head and mic extension.