Article written by: QuikLS
Well – I’ve wanted to do this for a while – and finally found a write-up by an M3 performance group that helped me get all the pieces together.
Here’s what you’ll need:
- Part Number 32-34-7-833-040 – Assy ‘SMG’ Switch Set CLP
- Part Number32-34-7-891-004 – shift lever set ‘wide’ SMG - larger paddles
- Two of - 2750241 SPDT 12V 1AMP Relay (RadioShack) $4.29 (I’ll explain why later).
The 32-34-7-833-040 – Assy ‘SMG’ Switch Set CLP comes with a set of paddles – but I ordered a set that had a longer reach.
Step One – get the steering wheel off – the hardest part of the entire job. Follow the steps in the service manual – disconnect the negative battery post (to disable the airbag) – and disassemble. You will need the $5 two-prong hub puller from AutoZone to get the wheel off.
Step Two – get the plastic shroud off the back of the wheel.
Step Three – spend some time lining up the paddles and using a dremel tool cut a hole so that the top part of the mechanism sticks through the plastic shroud. Looks a little ‘Borg-ish’ but it’s on the back of the steering wheel – so it will be hard to see.
Step four – mount the remaining hardware – and reassemble the steering wheel. Clip the yellow wires from the switches apart, leave the black ones together (with the eyelet) and ground them to the steering wheel frame using one of the screws the hold the plastic shroud in place.
Step 5 - Here is where the relays come in.
The BMW SMG paddles are typical switches that close a circuit when depressed – however – the LS SST signals the computer of a up-shift or down-shift by opening the circuit. So you have to create a small circuit that energizes the relay when the paddle is depressed, which open the circuit in the SST up-shift or down-shift link.
I wired mine into the console.
- Used +12V from the line running to lighter plug in the back of the console. I soldered this to one side of the relay coil on both relays.
- I ran a line from the paddle switches (the yellow line) and soldered one to the other side of the relay coil (one for each relay). Now when you pull on the paddle you’ll hear a slight ‘click’ of the relay.
- You’ll see the plug under the SST shifter – the red and yellow make the up-shift circuit while the blue and black make the down-shift circuit. You need to cut into the red line and wire it across the ‘normally closed’ poles of one relay (the one the powers when you pull the up-shift paddle). Cut into the blue line and wire it across the ‘normally closed’ poles of the other relay (the one the powers when you pull the down-shift paddle).
Here’s a shot of the wiring before I cleaned it up:
Reassemble the console and enjoy!!!
They work just like in the SMG BMW - pull toward the steering wheel. Works pretty good - the LS ignores any input from the paddles unless the shifter is in SST mode so there is no chance of an accident getting use to the paddles on the wheel.