Let Me In!!!

Take one $60,000 Boxster S, one 3-car 2-door garage with two LiftMaster 1255 openers (the old model, mind you!), and two other cars that CAME WITH HOMELINK, and you get one very frustrated Boxster driver who thinks it's ridiculous that he needs to fiddle with two bulky LiftMaster 81LM remotes in the compartment under his armrest. Various other people have done garage opener hacks -- either in the center console (where the seat heater rocker switch would be if I had one), or in a little unused switch panel on the very left of the dash. But that's not where I wanted mine to be -- I wanted to use one of the rocker switches on the left side of the dash console.

Well, SharkWorks actually makes an opener specifically for the Boxster, to go exactly where I want it. And they can even configure it to open TWO doors if needed. (And I need, I need!) Unfortunately, they don't support my older model LiftMasters.

So . . . I decided to do it myself. Overall, it worked out extremely well. Here are illustrated instructions for those wishing to do the same (or similar) hack.

Parts

The picture at left shows the two original LiftMaster 81LM transmitters. Each one is a single door transmitter; they are labeled "SINGLE" and "DOUBLE" because one controls the single door (on the right in the picture above) and the other controls the double door (on the left in the picture above). The LiftMaster 64LM mini transmitter actually has THREE independently programmable buttons, and is much smaller than even ONE of the other transmitters.

Here's the rocker switch I used -- a footwell light switch, part number 996 613 980 00. An excellent schematic diagram is available here (part of Yoseif's OBC Hack instructions). I chose this switch because it has an LED that can be used to indicate when the transmitter is operating, and it has a fairly nondescript symbol that will not be confused with other functions (such as window operation or door locks).

Some hacks recommend using a VW part to connect to the switch, to facilitate quick connect/disconnect. This is not necessary if instead you crimp 1/4" female disconnects onto the ends of the wires. I found a package at Radio Shack containing five 1/4" and five 3/16" connectors. The Radio Shack part number is 64-4039 (see picture at right).

The symbol on the footwell light switch is designed to light up when the dash lights are on (in other words, the switch is backlit). This requires running two extra wires to the switch, to provide +12VDC and return; the easiest approach is to "tap in" to existing lighting wires on another switch nearby. I found a package of "Tap-In Squeeze Connectors" at Radio Shack, part number 64-3053 (see picture at left).

Program the Transmitter

Before beginning, program the buttons on the transmitter. This will make it possible to test (repeatedly) as you proceed. Ahh, but which buttons?

The outside of the 64LM transmitter has a single large plastic button on the front, and two smaller buttons on the side. Opening up the case reveals that the three buttons underneath the plastic are virtually identical. The button behind the front plastic is labeled S1 on the circuit board and referred to as "-" in the LiftMaster manual; it is mounted flush against the circuit board. The buttons behind the side plastic are labeled S3 and S4 on the circuit board ("0" and "+" respectively in the LiftMaster manual), and are mounted vertically on the circuit board. The vertical mounting of these two buttons makes them ideal candidates for use, instead of the flush-mounted button. The reasons for this are:

	Each button has 4 contacts: 2 on the + side and 2 on the - side. The vertically-mounted buttons each have a + and a - contact soldered into the circuit board, but an extra + and - contact are left exposed at the top of the switch.
	Soldering to the bottom of the circuit board would make it difficult if not impossible to replace the circuit board in the case, because there is insufficient clearance below the circuit board for the wires to be routed. However, the top of the case has plenty of extra clearance for wires.
	Soldering to the contacts on top of the two vertically-mounted buttons means that the two buttons that will ultimately control the garage doors will be the buttons on the SIDE of the transmitter case. The button on the FRONT of the case will not be used; and this makes it very convenient to route the wires out of the case, by simply reassembling the case without the large plastic button on the front. (See picture of completed unit at right.)

(I felt that after reassembling the case, the two buttons that I chose to use should still be operational by pressing the buttons on the outside of the case.)

So . . . program the two SIDE buttons to control the two garage doors.

Wiring

Opener Controls

Look at the back of the switch, with the two vertical contacts in the center oriented at the TOP (and the single horizontal contact at the bottom).

	The vertical contact at the bottom left (BLACK wire in the picture) is the amber ON light (LED) return, and needs to be connected to the NEGATIVE (-) side of any pushbutton on the transmitter.
	The left vertical contact at the top center (GREEN wire in the picture) is activated when the lower portion of the switch is pressed, and needs to be connected to the POSITIVE (+) side of one of the transmitter pushbuttons.
	The right vertical contact at the top center (RED wire in the picture) is activated when the upper portion of the switch is pressed, and needs to be connected to the POSITIVE (+) side of a different transmitter pushbutton.

If you wire the switch in this way, one side of the switch will operate one garage door, the other side of the switch will operate the other garage door, and the amber LED will light whenever either side is pressed. (For those of you who only need to control one garage door, you can tie the two center contacts together and connect them to the positive side of the transmitter pushbutton.)

Switch Backlight

Look at the back of the switch again, in the same orientation (the two vertical contacts in the center at the top; the single horizontal contact at the bottom).

	The horizontal contact at the bottom is the +12VDC that powers the switch backlight.
	The remaining vertical contact over on the right is the backlight return.

You'll want to connect an additional wire to each of these two contacts. In the picture at the left, you can see that I used a RED wire for the +12VDC, and a BLACK wire for the return.

The other ends of these two wires need to be tapped in to the corresponding wires on another dash switch. You can use another rocker switch (that has a backlight) if you want to. In my case, the only other rocker switches were on the other side (beyond the radio), but my Boxster S has a backlit variable intermittent wiper control knob on the left side below the spot where I chose to put my garage door opener switch. So I chose to tap into that John Felker's installation instructions include an explanation of the connectors and identify the two pins that control the backlight of that know, but unfortunately they do not indicate which is +12VDC and which is the return. But through trial and error I figured it out.

NOTE: you might want to do the tap-ins LAST, when you install your completed switch in the dash.

I tapped my RED wire into the BLUE/GREY/BROWN wire leading to the knob, and my BLACK wire into the BROWN wire leading to the knob. The picture at the right shows the completed taps.

Circuit Board

I studied the transmitter circuit board for a LONG time, turning it over repeatedly in my hands, to figure out the + and - contacts on the three buttons. Fortunately, the case indicates how to insert the battery (+ vs. -), so I was able to trace enough of the signal path to do what I needed to do.

The + battery connector is labeled E1 on the circuit board, and the - battery connector is labeled E2. Moving along the circuit board from left to right in the picture, the FIRST (leftmost) contact on the button labeled S3 is NEGATIVE (-). The next contact to the right is POSITIVE (+). (A good way to test that these two contacts in fact operate the button is to take a wire and short those two contacts together; the LED on the circuit board will glow, and the garage door will operate.)

Continuing to the pushbutton labeled S4, the contact on the left is POSITIVE (+) and the contact on the right is NEGATIVE (-) -- i.e., the opposite of pushbutton S3. Again, test this by shorting the contacts with a wire.

Two final tests: use a wire to short the NEGATIVE (left) contact of S3 to the POSITIVE (left) contact of S4. You should get the same result as pushing button S4. Then, use a wire to short the POSITIVE (right) contact of S3 to the NEGATIVE (right) contact of S4. This should be equivalent to pushing button S3. These tests prove that the NEGATIVE sides of the pushbuttons are wired together (so that you only need to connect one of them to the rocker switch), and they also validate which is NEGATIVE and which is POSITIVE.

IMPORTANT -- DISCONNECT THE BATTERY WHEN SOLDERING!

You will connect 3 wires to the contacts. Connect the first wire to the leftmost contact -- the NEGATIVE side of pushbutton S3 (the BLACK wire in the photo). Connect the second wire to the contact next to it -- the POSITIVE side of pushbutton S3 (the RED wire in the photo). Connect the third wire to the left (POSITIVE) contact on pushbutton S4 (the GREEN wire in the photo).

Connect the battery and test. Hold the other ends of the BLACK and RED wires together; the LED should glow and one of your garage doors should operate. Next, hold the other ends of the BLACK and GREEN wires together; the LED should glow and the other garage door should operate.

Note that you have connected a wire to the POSITIVE (+) side of EACH pushbutton, but you've only connected one NEGATIVE wire. This is OK, because the NEGATIVE sides of all three pushbuttons are all connected in the circuit board.

Slide the big plastic pushbutton out of the top of the case, and carefully route the wires through the opening as you snap the top back on. Crimp a female quick disconnect onto the end of each wire, and attach the wires to the proper contacts on the back of the rocker switch (as explained above).

Test again! depress the "high" end of the rocker switch, and the amber LED on the switch should glow, and one of your garage doors should operate. Depress the "low" end, and the amber LED should glow, and the other garage door should operate. Swap the two center connectors if you want to change the association of your doors with the high and low ends of the rocker switch.

Installation

Carefully pry the left rocker switch panel out of your dash, using a small flat blade screwdriver. If you have other switches (or the intermittent wiper delay dial) connected, you can just let the panel "hang" there to complete the remaining steps, or you can disconnect them and take the panel out of the car to work on it.

Decide which switch position you want to use. I chose the top. To make access easier, I rotated the panel 180 degrees so that the top switch was now at the bottom, and turned it over so that I was looking at the back.

To remove the blank placeholder, insert a thin flat blade screwdriver between the blank and the housing, CAREFULLY pry them apart, and lightly pull back on the blank. There are FOUR little tabs that are holding it in place -- two on the top and two on the bottom. In the top photo at the left, I marked the location of the tabs. The photo at the right shows the panel with the blank removed, ready for insertion of the rocker switch.

Snap the your rocker switch into the opening. Make sure you push it ALL the way in, so that all 4 of the little tabs click. If you don't do this, the switch won't be properly seated in the panel, and could get caught behind the plastic edge of the panel when you press it.

Now would be the best time to route your 2 backlight wires to wherever you're tapping them in (to another rocker switch, to the variable intermittent wiper control knob, etc.) and attach the taps.

Gather up the extra length of wire and tie it to the transmitter case with a tie wrap or a rubber band. Tuck the transmitter into the space behind the panel, and snap the panel back in place. You're done!