Circuit 129
Your car

Fuses

Three boxes. One of them is why the radio is dark.

Photograph the card in your lid — numbering drifted, and lettered slots A–F are named on that card, not always on the plastic. Maps below are the common 1992–1998 R129 layout. Radio is fuse 9 plus letter A, not a 16 A red named B.

Engine bayTrunkBattery
Mainlink

Tap a slot. Colours: white 8 A, red 16 A, blue 25 A, green 30 A.

Battery & high-current distribution

Fuse Main

Battery positive distribution / jump post

A green-crusted trunk terminal will starve every module at once. Clean to bare lead, tighten, and dielectric-grease. Confirm voltage at the under-hood jump post while cranking and while the roof pump runs.

dead carno powerrandom resetdim lightsradio no powerroof
Where
The battery lives in the trunk, usually the right well, under a cover. A jump-start post is under the hood so you never have to drag cables through the cabin.
How to open
Disconnect negative first. Main fusible links and a few maxi fuses sit next to the battery. Corroded battery posts here will mimic a ‘dead radio’, ‘dead roof’, or random module resets.
Notes
A weak or poorly grounded trunk battery is the R129’s favourite red herring. Voltage must stay above ~11.5 V while the hydraulic pump cranks — the roof controller will refuse to play if it doesn’t.