Can I wire Rear Fog to Front Fogs w/out frying my system?
 

I love to work on my car but electrical stuff is Rocket Science to me, my grandfather would be appalled!
I bought an OEM Euro Rear Fog Lamp and I've researched enough to know that wires exist to plug into in the fender. I'm also told that there is a stray wire behind the dash that hooks to a 3rd lead on a ROW Euro Fog Switch that turns to turn on the rear unit.
My question do I need to put in a new switch will it put too much on the existing system or is it just hack and I should do it right? Also does someone have this switch to sell?

Thanks,

Scott:confused:

The fog light switch on most are already set up for this. The switch is a two way switch, it can be pulled out, to turn on lights, or it can also be turned, to turn on the light. It can even do both functions at the same time, being pulled out, and turned, for dual function operation.

Thanks Cab,

I've pulled and turned it but it simply unscrews from the switch behind the dash, this is why I'm confused i doubt Porsche would have designed two switches but I'm not sure. What is sure is that I have a U.S. spec. car. What do you think?

S.

That may be the cause, but I do now a lot of people that have U.S. market cars and their switch works how I described. When it pulls out, it is only about a 1/4", when it turns to the right, it is no more than a 1/4 turn. Hopefully this will shed more "light" on the subject. Tony.

The switch should be the same for a US or ROW '85 Carrera. Have a look at yours and see if you have an extra terminal that is unused. I'm not familiar with that year but the earlier cars had a terminal for the rear lights.

JR

I researched this, and found that there are two different switches (US/Euro). The switch on my '85 only pulls out - like 4flyboy, if I turn it, it simply unscrews.

HOWEVER, the rear defroster/defogger switch and the Euro fog light switch are the same (except for the emblems). A pull for one action (defog) and a turn for another (defrost) (or vice versa - can't remember).

Here's the part # from PP (#15):
OEM-91161314700
Switch, fog headlamp, switch for rear fog light - Brand: Genuine Porsche
$48.61

I've looked high and low on my '85 for the (supposed) rear fog light wiring - never found it. If you do find it, let me know. I'd also be curious if you find that there is an unused wire in the dash for the rear fog - again, please let me know.

http://forums.pelicanparts.com/uploa...1203709535.jpg

Steve this is excellent news I should have figured this out for myself it makes perfect sense! Thanks for the input I'll let you know if I find the wiring I'm working on this over the weekend.

Scott

Let's take this a step further. The switches are the same between the US and ROW cars. The difference you have noted is due to the fact that Porsche offered fog lights on the front only, rear only, or front and rear. Heated rear windows were available with single stage heating and dual stage heating. Heated windshields were also optional. Not all options were available in the US, or in every year, in some cases.

A switch designed to run fog lights on both ends of the car is the same as a switch for dual stage rear window heating. A switch intended for only one set of fog lights was the same as the single stage heated rear window switch.

911 613 147 00 is the correct two stage switch for an '85 Carrera, as Steve noted.

For what it's worth, I have found the rear fog light wire in a ROW car I own, which never had a rear fog light fitted. Given that I don't recall seeing an option for rear fog lights in the US during this period, maybe Porsche omitted that part of the harness on US cars. I can't remember if the fog wire was part of the tunnel harness or a seperate wire. A part number for a seperate wire is shown in PET, although no description or diagram is associated with it.

JR

When I installed my rear fog lamp on my 81 SC (US), there was FACTORY wiring on the driver's side, pushed up into the inside of my rear bumper. I don't know if Porsche wired all ROW and US car for this option, but my switch, when turned to the right, sent 12V to the wire at the rear. I still had to provide a ground wire, but really a simple install.

Reach up behind the driver's side rear wheel towards the bumper and see if you feel a small wiring harness. You may already have the wires available.

By the way, it's been 4 years and nothing has melted from running this small drawing (amps) lamp.

Javadog great stuff thanks for the input my car has the dual level fog option and Steve I've ordered the OEM-91161314700 not surprisingly this number comes up as both fog/defrost switch on Pelican one for $48.61 and one for $50.51 two different descriptions two prices same part #.
The two dollars doesn't concern me (he gave me the lesser price) but he couldn't assure me that I'd get the proper fog light emblem on the switch! Again not a big issue.
I removed the left rear light housing entirely when I couldn't find stray wires TMoreken. No luck but a ton of sand and STONES fell out so much so that I removed and cleaned the other side. I'm bummed at not finding a wire because this means that there won't be one behind the dash to solder up to the new switch. I'll have to run a new wire to the switch then fuse box guys? This is at the limit of my electrical abilities I'll have to do some studying.
THANKS for all the input.

Scott

My 80Sc has the same wire in the rear. I have never checked it for voltage so I don't know if it is connected on the other end, but someday I plan on installing the rear light. At least I know the wire is there.

Scott,

The fog light emblem is removeable, so you can reuse the original one from your car if the new switch doesn't have one. The wiring to the rear light is simple. Just one wire from the switch to the light and a ground from the light to the ground point in the left side of the engine compartment.

JR

I can handle that! Thanks for the tip Javadog.

S.

I have the wiring in the back for a rear fog, but no switch in the dash for the fog light option.
Any idea where I might find the wiring tucked away under the dash?

Behind the fresh air blower housing in the trunk.

JR

Thanks Javadog. gotta go in there any way to fix the blower motor.

4FLYBOY,

The wire(s) I'm talking about were accessible W/O removing the rear lamp housing. They were tie-wrapped from the factory above the muffler close to the inside of the rear bumper. I know they were factory based on both the material and age of the wire. You might want to jack up the driver's side, remove the rear wheel, and take a look with a flashlight to make sure they're not stuffed up in there. It's only one or two wires (#14?), so they'd be easy to miss with 20+ years of grime covering them OR You're car may not have them.

Running one wire to the dash is not that difficult. You can route the wire around the driver's side engine compartment and enter the interior where the speedometer sensor cable comes in. If you remove the plate that covers your shift coupler (behind front seats in middle), you will see the wires. Continue the wire through the tunnel, past the AC console and then hide it behind the loose carpeting we all have. I think someone already listed the correct spade to connect to at the switch end. If not, turn on your headlights, fog light switch to the right, and see which terminal yields 12V+ in that position. By trial and error, you'll figure it out. As for the ground, I simply used a ring spade connector behind the bolt that attaches the fog lamp. Remember, the entire body is your ground.

TMoreken,

Can't thank you enough I'll pull that left rear tire Saturday morning. Descriptions of where that wire might be have been vague this will settle it once and for all. I'll add to this post w/a picture if I find it and let you know if I don't.

Regards,

Scott

Sorry I didn't see this thread sooner...Here are some pictures for reference...

My car is a U.S. '81 911SC The fog switch is a US model, Pull for front fogs only.

The car is pre-wired in the rear for the euro fog. My Euro fog wires originate out of the Left Rear tail light harness...the sheath is more of a cloth type than the plastic type found on the rest of the wiring harness.

I have two wires in mine. Looks like a brown ground and a black hot.

The extra harness is about 18" long and is tied to the left rear tie-down hole in the back of the chassis.

Hope this helps everyone.

Based on the other poster's replys it seems like maybe the '84 and later 3.2 Carreras aren't pre-wired for the euro rear fog option...but the 911SC's ('78-'83) are.

Here are some pictures:



http://forums.pelicanparts.com/uploa...1204094461.jpg
http://forums.pelicanparts.com/uploa...1204094554.jpg
http://forums.pelicanparts.com/uploa...1204094612.jpg
http://forums.pelicanparts.com/uploa...1204094685.jpg

Wow this is an old thread. Just wondering if anyone has ever tried using a headlamp switch (911 613 029 03 ) which is a multi-stop. It would be cool to use a single pull switch to operate both front and rear rather than having to install a second switch to turn on the rear fog.

The switch you want to get is the same PN as the switch used for the rear window defrost.

It will be pull out for front fog lights and quarter turn clockwise for the rear fog.

You should be able to get a used switch.

Cooper

In my Swiss market 84 Carrera ROW I have to pull the headlight lever 1 detent and pull the foglight switch back to light up the front foglights and then turn the foglight switch to light up the rear foglight. If the headlight switch is in the full on or full off position neither foglight will operate. Only if it is in the parking light position. Interestingly my car does not light up the parking lights when the headlight is in the parking light position only a very dim light emanates from the headlamps.

All this nonsense drove me nuts after I bought it, when I was trying to figure out if the rear foglamp was operational or not, so I tried the owner's manual. Unfortunately it was in German, no joy.

Now to figure out the heating and vent controls. Lol.

The reason your fogs only work in the #1 stop on your headlight switch is because the grey wire for your fogs is on terminal pin #57. It's easy to check to know for sure by just removing your headlight switch. Just pop out the centre cap from under the rubber lip, and unscrew the 10 or 11mm nut and washer, then slide the knob off. You will also have to unscrew a little plastic cap from the shaft of the headlight switch, too. It has two little dimples so you can use a pair of needle nose pliers (or scissors or or two small screwdrivers or whatever) to rotate it off. The switch will pull out from under the dash. Just don't unhook anything when you're yanking it out by accident.

That grey wire supplies power to your fog switch which. When it is turned on, it will allow that to go to your fog light relay to switch the lights on. The current is quite small. If you want your fogs to be able to work under some different circumstance other than just having the parking lights on, you can move that grey wire to a different terminal on the headlight switch.

I moved mine to pin #75 so the lights could work anytime that the car is running. When driving on the highway, I often use my fogs instead of headlights to be visible. I also use 35 watt bulbs in my fogs to use less power and not heat up the plastic fog light enclosure to the melting point. I didn't want mine on pin #57 because I would need my parking lights on for them to work, so if for some reason I forgot them on and left my car, my fogs would still be on. This way, any time my ignition is switched off, my fogs also go off regardless of the position of either my headlight or fog light switch.

Here is a diagram to show when each terminal on the switch will be hot, in all the headlight and ignition switch positions. It indicates that anything on pin #57 will get power anytime the headlight switch is the first detent, and also if the ignition switch is either on or off.

http://forums.pelicanparts.com/uploa...1243114292.jpg.

Another thing about your car's lighting that you mentioned is that the front yellow "parking" lights are not like the North American car's running lights. They are ONLY signal lights. The true parking lights are when you turn your car off, you can flip the signal lever to the left or right turn position, and the turn signal lights will turn on to warn other drivers that your car is parked there at the side of the road in the dark. As well, there is only one lens for each side where the US models have two. On yours, there is another piece of rubber trim strip to the rear of your signal lens between it and the bumper bellows. This is where the US cars have another yellow lens.


Your headlights will glow like you say when the headlight switch is in either on position because of the small 4 watt bulb that is in the bottom of the light assembly. They are commonly referred to as "city lights." Your headlights should come on normally in the second position, but the city lights will stay illuminated.

As an example, you can see in this pic of my RoW car that the headlamps appear to be glowing, but not as brightly as if the they were on, and all my signal lights are also illuminated. The only way I could get the signals to do this is by turning on the hazard flashers and snapping the shot just when they lit up. This the only time when they will light up. And the headlight glow is because of the city lights.

http://forums.pelicanparts.com/uploa...1346471689.jpg

Thanks Canada Kev, although I have never tried any wiring before, I might just do the mod you suggested so I can leave my fogs on all the time and use them as daytime running lights, without killing the battery if I forget to turn them off. Bentley manual comming in the next week or so.

When I have the fogs on my rear running lights (not the rear foglights) turn on is this also the case for your car? I seem to recall that yours is a Swiss market car too, so I imagine the light configuration must be pretty much the same.

No, due to moving that wire on the back of the headlight switch, my fogs will work anytime the car is running. My running lights to not need to be on. If I wanted to use them as daytime running lights, I'd just leave the fog light switch pulled out and then they'd be on whenever the car is, and then they'd turn off automatically when I took the key out.

To make that wiring change, it's pretty easy. I've taken the switch out a number of times, and the hardest part (if you could call it hard...) is removing the plastic cap from the switch knob - just use a small screwdriver to pry it out. If you want any other specific info, just let me know.

EDIT: Actually, you may have the earlier style knob, so prying out the plastic cap might not be the best way. Other than the knob, the switches are operationally identical.

Thanks Kev I will look into it.

I guess the rear lights are on as a consequence of the "city lights" being on.

Yep. Part of the running light circuit. Other than the colour of the signal lenses, the tail light function, I believe, is the same between US and RoW cars.

On yours, the first notch will turn on the city lights, tail lights and allow your fogs to work. Second notch adds the headlights.

Kevin - your car looks awesome in that low light. Love the color too. Are those 17 inc wheels? Post some more pics if you have any others available. Thanks!

Thanks. Yup, 17 inch Zuffenhaus wheels.

Here's a couple pics for ya. Always willing to share.

Kills bugs fast.
OK fine, I suppose that's not really what you had in mind...
http://forums.pelicanparts.com/uploa...1346807812.jpg

http://forums.pelicanparts.com/uploa...1346807862.jpg

http://forums.pelicanparts.com/uploa...1346807885.jpg

http://forums.pelicanparts.com/uploa...1346807903.jpg

That should keep you satisfied. Thanks again for the interest.



.

Interesting question Tachin, I got a kick out of reading this old thread. The '85 is gone and I've regretted selling it since the day she left. I'm in the market for another 3.2 and plan to install that rear fog again......love this stuff. Hope that you get an answer. Scott

Taking the plunge and ordering the rear reflector with incorporated rear fog reflectors and bulbs (911-633-123-01). Will replace the current US fog light switch that pulls out to illuminate the front fogs with the two-stage switch (911-613-147-00) that controls front and back fogs by adding a twist capability. Also ordering a couple of spare 21W bulbs (900-631-127-90) and the three electrical connector parts to the reflector assembly (911-631-261-00, 944-612-548-00, and 944-612-547-00) just to make the wiring easier. My reference was the UK PET from the Porsche site.

More to follow...
:)

Another cleaner, simpler, and cheaper solution that Autofarm in the UK does is to install a red LED into the right reverse light housing and wire it to the rear foglight switch.

See here for bulbs (I'm sure there's a US source) LED for light bulbs - car or van . Custom 12v LED bulbs, white or red for rear fog lamps .

This gives the function, but if it's the look you're after, never mind.

Dru

Thanks RDM...going for the stock look though...parts arrive next week...

Just installed a rear fog light I bought off a fellow Pelican years ago. I don't use the lights for the license plate so I used the left license plate light wires to light the fog light. Maybe one day I'll install a single light for the license plate or when Mcgarrett tells me to.

All my parts arrived yesterday and will install over the next two weeks...looking forward to this mod!

No, no Tachin. Reread the thread. It's your fog switch, pull to activate front fogs and rotate to activate the rear! Very cool and just the one switch albeit the European dual purpose one.

I'm revisiting this thread myself because I sold my rear fog and want another to rig on my widebody!

Scott

Here's a link (http://forums.pelicanparts.com/porsche-911-technical-forum/167698-euro-rear-fog-light-5.html#post7198466) to my rear fog lamp install that is integrated into the rear reflector using the two-stage switch for my 88. Really enjoying it. With the two bright 21W bulbs, anyone who starts tailgating me gets a shot of these. They slow down real fast and back off...works every time.

I just completed my rear euro bumper install over the weekend and mounted the rear fog light housing this afternoon. Hope I mounted it correctly, please refer to photo.

I have no knowledge nor experience in tinkering with the electricals of any vehicle I have, so bear with me. After reading inputs on this thread, I would mostly go the route of what javadog has recommended. My 86 US spec came with a single stage fog light switch (pull only). Hence, I would order from host the two-stage switch (pull and turn) with part number 911-613-148-00-OEM. Moreover, I don't have the mysterious wire hidden on the rear driver side like some of you have so I will run a new wire from the rear to the switch.

While I am on it, I was thinking of making the front&rear fog lights work even with city lights only. I know a few of you guys did this. How do I do this? Sorry guys newbie here with stupid questions, lol.

I love the way the car looks if city lights on head light, side marker (photo of Canada Kev) plus fog lights work simultaneously.

Thanks!

http://forums.pelicanparts.com/uploa...1369197642.jpg

Looks good!

The side markers (and SIGNAL lights in bumper) are only illuminated because I shot the picture with the hazards flashing and caught them while lit. Normally they only work as signal lights.

If you want the fogs to work with just the running lights, you can pull the headlight switch and move the grey fog light wire from pin 56 and move it to pin 58L or 58R. That will move the power feed to the fog relay form the headlight circuit (lights need to be on for fogs to work) to the parking/running light circuit where they will need to be on to get fogs to work.

I have mine on pin 75 so the fogs (front and rear) will operate any time the ignition is in the "on" position.