BMW E46 Instrument Cluster Interior Lighting Wire

Who would think that how the E46 instrument cluster lights up when your turn the light switch on varies by the build date of the car? Up to 09/2002, there is a typical wire from the dimmable output of the light switch, through a splice, that goes to the instrument cluster just like all of the other dimmable items. From 09/2002, the instrument cluster receives a signal via K-Bus from the light switch to know that the light switch was turned on, and therefore does not have the wire as the earlier builds do.

What’s the problem? If your E46 is a build date from 09/2002, and you were to swap in an instrument cluster originally from an E46 with a build date up to 09/2002, the instrument cluster will not light up after you turn your light switch on. These earlier versions of the instrument cluster will only light up by receiving the power via the wire from the dimmable output of the light switch.

In the opposite scenario if a later production instrument cluster is put into an earlier production E46, the instrument cluster will light up as normal, but not because the earlier production E46 has this wire, but because all of the light switches broadcast the signal via K-Bus which is the method of how the later production instrument clusters light up.

This loose wire with the appropriate pin crimped on can be added to the X11175, 26-pin, Black connector of the A2 – Instrument Cluster Control Unit of a later production E46 to allow the earlier production instrument cluster to light up as normal. The unterminated end of this wire will need to be spliced into the dimmable output from the light switch and from the factory is part of the X908 ultrasonic splice with other Gray/Red wires. This ultrasonic splice is buried within the wire harness some where between the instrument cluster and before the wires go under the heater core, while for most people it will be much easier to splice directly into the wire from the light switch (X12-47).

Wiring Details:

• 0.50mm² Gray/Red* – X11176-7 to X908, Ultrasonic Splice, Instrument and Location Lighting

Notes:

* From the factory this wire is 0.35mm², while we don’t have Gray/Red available in that size and most people find 0.50mm² easier to work with.

– Having this wire present if you were to go back to a later production instrument cluster will not affect anything.