New lighting functions

I rewired my headlights and driving lights to permit some new operation modes. Here's a list:

Flashing of the driving lights with the stalk (while the headlights are off and down)
Automatic operation of the driving lights with the high beams (enabled/disabled by an additional toggle switch)
Late-model headlamp motor operation (e.g. lights down when HL switch is half-way out)
Independent operation of the driving lights from the headlights (w/ the ignition on)

These modifications required some rewiring and the addition of two standard (black, round) relays and sockets, a diode, and a micro toggle switch. The conversion is very clean to do and looks nearly OEM.

EASY ALTERNATIVE!! - If you want a really simple way to flash your fogs when your headlights are off, just buy this part from JWest: http://www.jwesteng.com/porsche/fog.htm

Please note - the procedures will be only specific to a 1970 914. There are some small variations from year-to-year, and they should be apparent by reviewing the wiring diagrams at Pelican Parts.

The Conversion....

Background

The wiring diagram that I will use for all of my discussions is at: http://www.pelicanparts.com/914/parts/electrical/914_electric_71a.jpg . The later model cars may have some slight differences, check the diagrams at Pelican Parts before you proceed.

Parts Needed (get this stuff BEFORE you start...!)

Two standard 914 black round relays and rubber sockets. I got mine from Ebay, I bought a full fuse box panel for $20. Your best bet would be to go to a 914 junkyard and get these off of a donor car. The relay sockets I used have a rubber prong on the backside for mounting onto the fuse panel. Be careful when locating these sockets - most have connectors and wires for terminals 30, 85, 86, and 87 - but the socket for the buzzer only has two connectors. Make sure at a minimum you get sockets with the four connections. If you are lucky, see if you can get a socket from the front headlight door relays (#50) - this socket has an additional connector to terminal 87a, which is needed. If you can't get one, it's a simple fix to solder a wire to the pin of 87a on one of the relays instead.
Micro toggle switch (from Radio Shack)- this switch is used to enable/defeat the automatic high beam/driving light operation.
Diode (Radio Shack)- used to block control signals to the fog lamp relay from turning on the high beams.
Crimp-on connector assortment - you will need push on connectors, splices, ring connectors, etc. Best bet is to go to Home Depot or Lowes and buy an assortment.
Crimping pliers (comes with some assortments...)
Piggyback push-on connectors. You can get these at Radio Shack, too.
1/8" and 1/4" shrink-wrap tubing
Heat gun (get a real gun - most hair dryers don't cut it with shrink-wrap)
Soldering iron and rosin-core solder
Other standard hand tools (e.g. diagonal cutters, pliers, etc.)

Theory

Part #26 is the ignition switch, which also includes the turn signal indicator and stalk. The stalk contacts are between terminals S and 31 (ground). Pulling back on the stalk momentarily pulls terminal S to ground. S is connected (yellow/red) to terminal S of the "combination" or high/low beam relay, #27 (located in the RH top corner of the fuse panel). Jim Thorusen pointed out to me that the internal wiring diagram of this relay shown is incorrect - just above terminal 56a, there is a connection shown that goes to the top of the relay coil - it actually is connected to 56, not 56a. If you look at the later schematics at Pelican Parts, you'll see that this was corrected. When the lights are on, there is +12V applied to 56 - the momentary contact to ground with the stalk brings terminal S on the relay to ground, and toggles the high/low beams.

The auxiliary lights are controlled by relay #53. The first trick to notice is that the ground for the relay coil is supplied through the high beam filaments. This means that when the high beams are switched on, and the fog lamp switch is on, +12V is applied to both relay coils - and the relay drops out, preventing the use of the fog lights with the high beams. It makes sense - unless you are replacing the fogs with driving lights. The other side of the coil gets +12V through the fog lamp switch, #36. Note that the +12V source for the fog lamp switch comes from the headlight switch, and only when it is halfway or fully out. You cannot turn on the fog lamps unless the switch is on. We'll need to change this if we want to be able to turn the lights on w/o the headlights being on.

Conversion

Two relays are required. The first relay routes the ground from the stalk, depending on if the lights are on or off. If the lights are on, the relay connects the stalk wire (yellow/red) to the combo relay (#27), just like the OEM wiring. When the lights are off, the stalk wire to the coil of a second relay. A second relay is required because the control signal for the fog lamp relay (#53) is +12V, not ground. The second relay "inverts" the signal and supplies +12V to the fog lamp relay. The other functions are realized by rewiring the combo relay and fog lamp relay.

Disconnect the positive terminal on the battery - do not reconnect the terminal until the job is done and all of the connections have been double checked for continuity and accuracy!!!
Remove the two screws from the fuse panel and let it hang down.
Remove the headlight switch knob and aluminum trim ring. There should be enough slack in the wires to let the HL switch hang down. Work slowly and deliberately - do not yank any wires or pull hard, or you will be looking at a complex repair.
Check your headlight switch wiring against the wiring diagrams at the Pelican Parts site - there may be some differences. The switch on my 1970 has no connection at all to accessory power (terminal 15 wire over to the ignition switch). Instead, terminal 30 is jumpered to terminal 15 - this is the OEM wiring, verified with other 1970 owners.
Locate terminal 58b - there should be a black/blue wire and a gray wire attached. The black/blue wire is the +12V source to the fog lamp switch. Cut the wire at the connector and pull it back - extend the wire with 14 gauge copper wire using a insulated butt connector. Attach a insulated push-on connector to the end of the wire and connect it to the fused side of fuse #8 using a piggyback connector.
If you have a 1970 and you want "late model" headlight door operation, check how many gray wires you have on terminal K. If there are 3 wires, your headlights are wired to pop up when the light switch is pulled from fully in to halfway out. If you want the lights to stay down in the parking position, you need to ID which gray wire is the door control wire and clip it. One of the gray wires is simple to ID, it goes over to terminal 58b. The other wire should have a number on the wire housing. This wire goes over to the fuse box, to fuse 7. You should see the same number on the wire just above fuse 7. The remaining wire is the one you clip. Attach a push-on connector, and piggyback the wire onto terminal 56. Insulate the piggyback with 1/4" shrinkwrap. Your lights will now stay down when the switch is pulled out to the parking position - BUT - after you turn on the headlights, and they lights pop up, when you go back to halfway, they will still stay up. This is because the "lower" command line (green/purple wire on terminal 30b) is only actuated when you push the switch fully in. If you try to defeat this function, perhaps by moving the "lower" control line to terminal 57, it may work - I left mine alone.
Look at your fuse panel. On the 1970's, there is an unused relay socket plug hole in the lower RH corner, one of your new relays will go here. I put my other relay on the underside of the front firewall, just to the left of the floor heat vent. It may just have been my car, but there was a hole already there exactly the size needed for the relay socket prong! If not, drill a hole here to put the relay in later (don't insert the relays yet, there's more wiring to do).
Drill a 1/4" hole just above the LH fuse box mount on the panel for the micro toggle switch.

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