My car has 190k , well maintained, well cared for.
recently my radio started turning off when light switch tubes on, windows used, brake pushed occasionally, just don’t understand. The radio is aftermarket. But never had a single issue with the radio since install some times ago. Anyone have any idea what could be causing this ? The radio is installed with a wire harness . Any help would be good

 

check the fuses, 240's use old fashion 'euro' ceramic fuses, the tin plated ones available are awful and very prone to corrosion and making poor contact.

I replace ALL such fuses with Flosser brand copper/brass ceramic fuses, these are far superior and solve lots of electrical gremlins in both 240's and vintage Mercedes that also use the same fuses.

Also check your system voltage. with a fully charged battery at rest with the engine off for several hours, it should be about 12.6V. With the engine running, it should be around 13.6-14.2V I've had radios shut down when the voltage gets low.

finally, check your grounds. most stuff behind the dash on a 240 is grounded on either hte right or left side of the center console frame

 

The min I turned the key on after replacing red fuse it popped. What now ?

 

Red fuse popped

Missing spot is where red fuse popped

 

well, that means there's a short to ground on that circuit. not sure off the top of my head what fuse that is, or what it powers.

 

if thats fuse 11, random google searches suggest thats the transmission overdrive relay, and the seat heaters (if any).

 

On the inside of the fuse cover plate it says what each fuse is for.