Woohoo! Mission successful! I have this keyless entry module installed and it works perfectly! Here's a summary of how it went:
I noticed that my silver colored factory alarm module has two connectors. One is ten pins, the other is six pins. The keyless entry module has a "Y" cable with male and female ten pin connectors. I simply connected this keyless entry module in-line with the existing ten pin connector so that it is sitting in-between the factory ten pin connector and the factory alarm module.
I reconnected the car's battery (yes, I disconnected it before I started) and gave the remote a try. Partial success! The un-lock button works but the lock button does not. The un-lock button, when pressed once, disarms the factory alarm (red light stops blinking) and when pressed a second time, unlocks all the doors. Fine. The lock button however was not so simple. When pressed, it would arm the factory alarm (little red light begins to blink) but it did NOT lock anything!! no good!
Next I decided to see what the function of the loose red wire was. I hooked up my el-cheapo $8 multi-meter to the red wire and to ground. Some brief testing revealed that when the lock button was pressed on the remote, this loose red wire would give +12v for about 1/2 or 3/4 of a second. that's good!
Next step was to determine where I could send this 12v so that it would lock all the doors. I took my multimeter and began testing wires. I found that when the doors were locked with the key, there is one wire coming in from the drivers door which goes hot +12v for half a second. Super!
My next step was to run a wire from a constant +12v source to this wire from the drivers door. With all the doors unlocked, I touched the constant +12v to the drivers door wire and Presto! All the doors locked!
The next step was easy. I spliced the loose red wire from the keyless module to this wire from the drivers door. So now, when I press the lock key on the remote, it should send 12v briefly to the wire from the drivers door and lock everything. A brief test showed this theory to be valid.
Success!
Now to figure out where to mount this keyless entry module. I swear, the VW engineers must have specifically designed this under-dash area to prevent the mounting of this module!! I finally decided on a so-so location (I may relocate it later). I used two zip-ties to hold it to the under-side of the fuse box. The keyless module has two mounting holes and the fuse box has "slats" on the underside so the zip-ties actually worked quite well.
Here are some photos of the install.
Here's the keyless entry module's "Y" cable and how it plugged in. The blurry connector in the top right of the photo is the original ten-pin connector that went straight into the factory alarm box:
Here's the cluster of wires coming in from the drivers door. There are three connectors here. Pin 8 of the middle connector (it's a grey wire) is the one I spliced into. Sending +12v to this wire causes all the doors to lock. The red wire going straight up (top center of the photo) is what goes to the harness of the new keyless module.
Here it is mounted up under the fuse box. I don't really like this location but I couldn't find a better one. Suggestions anyone??
My next step for the project is to use a relay to connect that loose red wire (the one that gives +12v for 1/2 second upon pressing the lock button) to some wire from the headlight switch. That way, when I press lock, it will blink the lights one time, giving me a visual confirmation that the car is locked.
Note that if you attempt this install, have a good chiropractor lined up for afterwards. The good Lord did not intend for people to contort into such positions! /images/graemlins/eek.gif Enjoy these photos because they were not easy to take!!
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UPDATE: I relocated the keyless entry module to the back side of the driver's foam kneepad using some double-sided epoxy-tape. This is a much better location than beneath the fuse box.