I've undertaken this little project for johnrando, he has a SprintBooster installed in his car and it uses a remote button to switch the unit between the three modes and provide color indication of the selected mode. The button that comes with it looks like this:
John wanted a cleaner, more OEM look so he purchased a button assembly from a convertible M3 - which is the same assembly but with the addition of a SPORT button and our goal is to use that button to switch the modes of the SprintBooster.
Taking apart the SprintBooster button reveals a rather simple assembly with one red LED, one green LED, and a push button:
So far so good, next is the SPORT button:
In the center image you can see there are two LED's. The tiny LED1 is the backlight for the button, which we want, to keep the button looking OEM. LED2 is the indicator for the button, and SW1 is the actual switch. The right picture is there just to show how they shielded the output from the indicator LED from the backlit area.
Now that I have taken apart and examined everything here is the plan:
1. Remove LED2 from the SPORT button
2. Remove the red and green LED's from the SprintBooster circuit board and glue them side-by-side onto the SPORT button circuit board where LED2 currently sits. This will be a little tricky as they barely fit within the shielded area.
3. Remove the surface mount switch, SW1 from the SPORT circuit board. The terminals for the switch can be seen on the right and left of the switch and we will bend those up slightly so they no longer contact the circuit board, then glue the switch back in place.
4. Next we just need to soldier wires onto the two LED's and the switch and run them back to the SprintBooster circuit board where they were originally located.
That's the plan and I will post more pictures as I progress but what we should end up with is an OEM SPORT button that switches the SprintBooster modes and displays the OFF-GREEN-RED mode indicator.
Sounds simple enough <<< Famous last words
************************* PROGRESS UPDATE *************************
Steps 1, 2, and 3 above are done:
On the left shows the original LED and switch removed from the SPORT button circuit board and how I have carefully bent the terminals of the switch upwards so they won't push through the JB Weld and make contact with the board.
The middle shows the thin layer of JB Weld that will hold the new components in place and act as an insulator to keep them from making electrical contact with the board.
On the right shows the new LED's and the modified switch set on the JB Weld in their new positions.
One important thing to note is that current only flows one direction through LED's so I placed black dots on the side of one and the top of the other before removing them from the SB board and took a picture. This will enable me to wire them back to the SB board in the same orientation and not have to bother with testing to see which side is which and which one is green and which one is red.
************************* PROGRESS UPDATE *************************
Ran the wires to the components in their new positions:
If you follow the traces on the SB board you can see we only need three wires.
************************* PROGRESS UPDATE *************************
Finishing up.
This is the wires soldiered onto the SB board and then covered with a bit of shrink tube. There is plenty of empty space in the whole button assembly so this is all tucked inside.
This is the back of the SPORT button in the housing and the wires routed out one of the vent holes in the back of the assembly.
Here it is back in the car with the red LED active.
Here it is with the green LED on and you can see the backlighting still works giving it an OEM look
William.
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