I'm on the look for a wiring diagram, but in the meantime, does anyone know what the following wires do in the back of the Instrument cluster, and where do they go?:

red/white?
red/yellow?
yellow?

Thanks!

If you had a tachometer, the red/white wire would go on the terminal marked #1 on the back of the tach. This is the signal from the coil. Most 240s from the early 80s onward came with this wire regardless of whether it had a tach or not, so it frequently causes confusion when someone removes the cluster and ends up with a wire going to nothing.

red-white tachometer.
red-yellow fuel pump relay

Red/white - only used with optional tach. goes to tach if present.
red/yellow - lower right hand corner if facing dash from front.
yellow - almost in center but slighly to right of speedo connector.

What year is your 240 (presuming that is what your driving)? I have the factory wiring diagrams from 75-84 so I'm sure I can send you what you need if you fall between these years. Good Luck!

Sincerely,

Nickvjr
1979 264GL 119,950

Mine is a '90 240DL Wagon.