TROUBLESHOOTING THE LED HEADLIGHT/FOG LIGHT PROBLEM
After installing LED headlights, sometimes the fog lights don't work. There are 2 ways to address the fog light issue. One is to add resistors as my brother did in post 43- the other is to isolate the fog lights from the high low circuit to operate independently starting in post 80. It is actually the way I would prefer to address it as it's simpler and easier to do without adding much of anything.
http://www.914world.com/bbs2/index.php?showtopic=264737&hl=resistor&st=25
914 FOGLIGHT REWIRING INSTRUCTIONS
Ever wish you could use your foglights without having to have your headlight on, or wish they would stay on when you switch on the highbeams? Well, this set of instructions will explain how to rewire your 914 so that you can!
This set of instructions has been compiled from a variety of sources:
- Instructions from GPR (no longer on the web as far as I know).
- Instructions from a technical article in Porsche Panorama July '89.
- Studying the wiring diagrams from the factory manuals (note: the wiring diagrams in the Haynes manual for '75 and '76 cars is incorrect when it comes to the fog light wiring, so do not use that diagram as a reference).
DISCLAIMER: I have only done this conversion on my '74 914. These instructions may or may not be correct, and cannot account for any previous re-wires that may have been done to your electrical system. So follow these instructions at your own risk!
The first step is to figure out how you want your fog lights to work. From the factory, your fog lights will only operate when the headlights are on ('70 and '71 cars can use their foglights with the running lights), and will turn off when your headlights are switched to high beams.
- Conversion #1 (choose 1a or 1b), will modify when you are able to use your fog lights.
- Conversion #2 will keep your fog lights on when using high beams.
Conversion 1a: Fog lights enabled with the running lights. This option will enable you to use your fog lights anytime your running lights are on. This is my preferred method because I can just leave my fog light switch on permanently. Whenever I want just the fogs, I pull the headlight switch to the running light position, and of course, they stay on with the headlights as well. '70-'71 cars (4cyl and 6cyl) already come from the factory wired for this.
Conversion 1b: Fog lights enabled with the ignition. This option will allow you to turn on the fog lights anytime the igniton is turned on. This option is best for people who want to use their fog lights as daytime running lights, or for those who simply want to use their fog lights without any other lights being on.
Conversion 2: This option will enable your fog lights to stay on when the headlights are switched to high beam. This is a completely separate change from options 1a or 1b. Personally, I did not see the purpose in doing this (I very rarely use my high beams anyway).
Conversion #1 Instructions
Disconnect the negative side of the battery.
Remove the headlight switch from the dash mounted location and let it hang down below the dash.
Locate the following black wire w/ blue stripe:
'70-'71 914-4 and 914-6: Black wire w/ blue stripe will be plugged into the #58b terminal on the headlight switch, along with a grey wire. '72-'73: Black wire w/ blue stripe will be plugged into the #56 terminal on the headlight switch, along with a grey wire and a red w/white striped wire. '74-'76: Black wire w/ blue stripe will be plugged into the #56 terminal on the headlight switch, along with a red w/white striped wire.
Carefully cut the black wire w/ blue stripe as close to the end (spade terminal) as possible leaving no part of the wire exposed. Crimp a piggy-back spade connector to the end of this wire. A piggy back spade terminal looks like this:
Conversion 1a (do this step if you selected option 1a above): To enable your fog lights with the running lights, locate the 'K' ternimal on the headlight switch and remove the connector that is attached to it. Plug on the black wire w/ blue stripe and then piggyback the wire that was originally on the 'K' terminal.
Conversion 1b (do this step if you selected option 1b above): To enable your fog lights with the ignition, then locate the #15 ternimal on the headlight switch and remove the connector that is attached to it. Plug on the black wire w/ blue stripe and then piggyback the wire that was originally on the #15 terminal.
Now put the headlight switch back into place and continue on to conversion #2 if you decided to do that modification as well. Otherwise, go ahead and hook up your battery and test out your fog lights.
Conversion #2 Instructions
Disconnect the negative side of the battery.
Remove the fuse cover and remove the screws which hold the fuse block plate in place - pull down the fuse block assembly and let it hang.
Locate and cut the following white w/blue striped wire:
'70-'71 914/4: First, you need to locate the combination relay. I believe it is mounted on the fuse block panel. The white w/blue striped wire will be attached to the 'F' terminal on the combination relay (along with a plain white wire). Cut this wire as close to the relay as possible leaving no part of the wire exposed. '72-'73 and 914/6: There will be two white w/blue striped wires attached at the #1 fuse on the fuse block. One of these wires goes to the high beam indicator in the tachometer, the other is for the fog light relay. You need to determine which is which (trial and error, multimeter, etc), and leave the high beam indicator wire in place. Cut the other (the one for the fog light relay) white w/blue striped wire as close to the end (spade connector) as possible leaving no part of the wire exposed. '74-'76: The white w/blue striped wire is attached at the input side of the #1 fuse on the fuse block (input side is toward the rear of the car). Cut this wire as close to the end (spade connector) as possible leaving no part of the wire exposed. Note: There is another white w/blue striped wire attached to the output side of the #1 fuse - leave this wire alone as it is for the high beam indicator light.
Now you need to permanently ground this white/blue striped wire. You will notice that there is a ground connection located at the upper left side of the fuse block mount with a bunch of other brown wires held down by a 13mm nut. You may need to splice in a few inches of additional wire to reach this ground point. Crimp a solderless terminal which will fit over the ground stud onto the wire, and fasten it to the ground connection with the other wires.
Now put the fuse block back in place, and hook up your battery. Your fog lights should now work with the high beams!