Sandy

Here's some additional info about the latching relay, which I meant to include in my reply: The relay appears quite large in my image, but actually measures only approx. 1 & 5/8” (including the pin length) x 1 & 1/16” x 13/16”. When plugged into its socket, the length of the combo increases to 2 & 1/8”. However, the socket pins can be bent over easily and unused pins clipped off to shorten the package slightly. You can always tell, visually, which position the relay is in. It has a little red-orange, rectangular flag inside its case at the top. You can see it at the corner of the white placard. When the relay is in its SET position (opposite the position I drew the relay contacts in my diagram), the flag comes into view. When the relay is in its RESET position, the flag disappears from view.

Jeff is correct. To obtain a hard ON & OFF function from the momentary-action FWL switch contacts requires a latching relay circuit. Here's a mechanically-latching relay I obtained from Digi-Key. It's an OMRON MY2K-US-DC12 (Digi-Key Z2056-ND). It cost $14.20 and is quite useful for many 12 volt circuits that are controlled by switches with momentary contacts. The DPDT contacts can handle at least 3 amps. The latching and unlatching coils draw only 60 ma. and 120 ma. at 14 volts. They draw current only while the FWL switch toggle is being pressed. The relay then REMAINS in the position it was toggled to, drawing no current. The image shows part numbers for a relay socket and retaining clip for mounting the relay on a metal bracket or chassis. A 25 mm. x 22 mm. cutout is required. The socket cost $1.36 and the retaining clip $1.38, locally. Radio Shack doesn’t carry equivalent hardware. The socket could be eliminated, because the relay's pins have small holes in their tips for securing wires. If you're skilled in basic soldering, you should have no trouble soldering connecting wiring ends onto the pins. Use short lengths of heat-shrink tubing for insulating the soldered connections. I would think that the relay, without a socket, could be mounted near the FWL switch using Velcro, or double adhesive-backed foam tape. I've run some tests with the relay and it seems extremely immune to vibration. I've included a suggested relay hook-up diagram below. It includes connections for the FWL switch's nite illumination LED. The amber annunciator LED in the FWL switch will illuminate when the relay is in the RESET (OFF) position. This is the relay position that will remove power from your device. The "consumer-switched-off" bus coming from the alarm C.U. provides switched +12 volts to the rear window defogger switch on a RED/BLACK wire. That bus powers all the interior lights and is handy to tap into for powering the FWL switch LED and the latching relay coils. The bus goes dead 10 minutes after locking the car, or after 2 hours, if you don't lock-up. Another option is to tap switched power from the GREEN/BLACK wire of the telephone prep. connector under the forward, center console. You might want to do this if you're concerned about the amber LED in the FWL switch remaining illuminated for awhile after leaving the car. The LED draws a negligible 20 to 25 ma. If your device draws a large amount of current, the +12 volts input that is wired to relay contact 11 may need to be obtained from a separate, fused, ignition switch controlled source, such as the telephone prep. connector (GREEN/BLACK, 7.5 a.), instead of the RED/BLACK source.

The image above, shows schematic diagrams of an unmodified 996TT spoiler control switch and a FWL switch to help you to understand my comments below. As you can see on the FWL switch schematic, the switch is really designed to switch a positive voltage (+12v.) coming in on pin 4, not a ground, as is required for OBC operation. I say this because the anodes (black triangles) for the nite illumination LED and the amber annunciator LED are connected internally to that pin. For the LEDs to conduct and illuminate, the voltage on pins 3 & 5 must be more negative than the voltage on pin 4. The internals of a FWL switch are typical of several other PAG switches. A couple of exceptions would be a convertible top switch and a 996TT spoiler control switch. Those switches have their LEDs isolated from their switch contacts, the way I did it to the FWL switch in my spoiler-extended light mod. By keeping the contacts isolated, the switch contacts can be wired to switch either +12v. OR a ground. With a ground tied to pin 4, as would be the arrangement in the OBC mod., there's no way an unmodified FWL switch can have nite illumination with either a positive or negative dimming voltage line connected to the nite illumination LED cathode (pin 3). So, how do you get nite illumination for your OBC switch without having to do some soldering work on a FWL switch?? Here's one solution you might want to try: You can remove the cap (toggle) from your FWL switch, snap it onto the base of a 996TT spoiler switch body and use that combo to toggle your OBC, instead of using the FWL switch body. Also, anytime you need a "non-descript" switch that doesn't require an amber annunciator, you'll have one by performing this same task. You would then have a switch that has its LEDs isolated from its switch contacts. One thing though, you'll have to paint over, or cover up, the surfaces of the little clear plastic "lens" inside the FWL switch cap. This will keep the nite illumination LED beneath the lens from shining through the lens and looking like an illuminated annunciator light. The lens can be removed from the cap for painting as you can see in the image below. There are two methods available for connecting up the spoiler control switch pins for nite illumination: The LEDs' cathodes (pin 5) can be wired to a negative dimming voltage line (Grey/Blue/Brown) and have +12v. on their anodes (pin 3), OR, their cathodes can be wired to ground and have a positive dimming voltage line (Grey/Blue/Red) on their anodes. The Grey/Blue/Red line is available on the rotary windshield wiper interval control (if you have it installed). Here's what the connections should be for using the body of a 996TT spoiler control switch for your OBC mod: Pins 1, 2 & 4 should be connected to your existing OBC control wires, with Pin 4 connected to the ground wire. Pin 3 should be connected to a +12v. line (Red/Black, not battery-direct powered), available at the rear defogger switch. Pin 5 should be connected to a Grey/Blue/Brown line.