Wiring The New Harness

This section applies to E38, E39, E46, E53, E60, E61, E63, and E83 retrofits where the vehicle did not come pre-wired for an electrochromic mirror. If your vehicle already has a connector behind the windshield mount, you can skip this section.

Overview

OEM Approach

BMW offers a complete wiring harness kit for this retrofit:

Part Number: 61120140175
Compatible with: E38 / E39 / E46 / E53 / E60 / E61 / E63 / E83

Available from: FCP , Turner , ECS

This kit includes all necessary wiring, connectors, and installation hardware. However, it’s quite costly for what is essentially some wire and a connector.

Budget-Friendly Alternative

DIY Solution: If you don’t mind sourcing parts and wrapping harnesses.

Required Components:

Connector:
- Available from Tulay’s Wire Werks (connector + pins kit)
- Can be sourced from junkyard components: clockspring, mirror, driver window switch, turn signal stalk, wiper stalk, etc.
  
  Note: This connector uses various BMW part numbers depending on color and can’t really be found by it.
Pins:
- Female: 61138722287 (for 0.35mm wire)
- Male: 61138722314 (for 0.35mm wire) - Don’t actually need, just providing for reference.
Wire: 22 AWG / 0.35mm² wire (various colors)
Tape: Tesa 51608 harness tape - Any harness tape will do but this is what BMW uses.

Required Tools:

Crimpers: I have these IWISS crimpers , but any that handle 0.35 mm² (22 AWG) terminals should work fine.
Scissors: For cutting wire and tape.
Wire Strippers: Anything that can strip 0.35 mm² (22 AWG) wire works.

Wiring Diagram

Your connector layout may look different depending on chassis, but the wiring functions are consistent: signal, ground, and power.

In this diagram, A22 (mirror) connects with X18246 (10-pin connector):

The relevant wires are:

Pin 1 — S_RS+: signal wire for the mirror’s auto-dimming function
Pin 3 — 15<24: switched power (Terminal 15, Fuse 24)
Pin 10 — 31E: ground

Here is the pin layout for the connector itself:

If you sourced your connector from a mirror at the junkyard you may notice extra wires on pins 4, 5, 6, 7. These are for outside mirror dimming and can be disregarded or this retrofit.

Important: This wiring diagram is specific to my E83. Pin destinations may differ between models, but the wires coming out of the mirror itself are consistent. Your fuse will not be the same.

Wiring to Chassis

Now this is the part where you’ll have to consult your specific vehicle’s wiring diagram, as it will be different for every model.

Shortcut Wiring Method

If you want a simpler approach, you can tap into nearby switched power and ground instead of running wires all the way to the fuse panel.

For example:

Power (Terminal 15) → use the sunroof harness
Ground → nearby ground point

Because the mirror’s current draw is very low, this is generally safe.

You will still need to run the S_RS+ signal wire to a valid connection point. In many cases, tapping into the existing run is sufficient if the signal is already shared with other systems. If not, route the wire directly to the originating module.

Always double-check what you tap into. Never splice into safety-critical systems such as airbags.