1987 911 headlight wiring issue

[jayleon]

I have an '87 factory turbo look 911. my turn signal switch went bad a couple of weeks ago, so i bought a replacement from pelican. on paper, the replacement should have been straightforward.

I pulled the steering wheel, dropped down the head light switch and removed the old turn signal switch. i disconnected the leads from the old turn signal switch one at a time from the pins on the headlight switch and replaced with the corresponding wire from the replacement turn signal switch so as not to create a problem. no such luck.

for reference, the headlight switch has three positions; off, first (middle) and second (fully pulled out). When the headlight switch is in middle position, the marker lights should be on and the fog lights should be available if you pull the fog light switch. In the second (fully out) position, marker lights, headlights and instrument lights should be on and fog lights available. When everything is working according to design, when headlights are on and fog lights on, fog lights are only on when headlights are on low beam. Fog lights turn off automatically when headlights are switch to highbeam.

upon reassembly, high/low beams and turn signals worked fine. However, I soon noticed a couple of minor electrical issues. the front and rear marker lights do not work except when the headlight switch is fully extracted (the second position). the marker lights should be on when the headlight switch is in the first and second position.

Secondly, the lights on the instrument panel are on when the headlight switch is in the first (middle) position but not when the switch is in the second position. In other words, when the headlights are on, the Instrument illumination goes out.

Lastly, the functioning of the fog lamps is reversed. In other words, the fog lamps come on when the hi beams are turned on and go off when the Low beams are switched on.

despite my best efforts, I think a wire became disconnected from the headlight switch when I removed it. don't remember which one at this point. However, Despite reviewing the wiring schematics in my Bentley manual and several pertinent posts on this forum, I can't get the matter sorted out. some of the posts are for pre-87 Porsches. earlier 911's had a different pin configuration on the headlight switch. some of the posts concern ROW vehicles that appear to involve different colored wires and wiring configurations.

wires from three sources come together at the headlight switch: that is, from the ignition switch, the turn signal switch, and the bundle of wires that seems to feed the marker lights, license plate lights, etc.. I can account for all the wires coming from the turn signal switch to the headlight switch. try as I might, I cannot account for all the wires I am seeing from the other two sources.

What I'm looking for is a simple checklist that indicates where each wire from each of these sources connects to the headlight switch.

[86 911 Targa]

Originally Posted by jayleon

I have an '87 factory turbo look 911. my turn signal switch went bad a couple of weeks ago, so i bought a replacement from pelican. on paper, the replacement should have been straightforward.

I pulled the steering wheel, dropped down the head light switch and removed the old turn signal switch. i disconnected the leads from the old turn signal switch one at a time from the pins on the headlight switch and replaced with the corresponding wire from the replacement turn signal switch so as not to create a problem. no such luck.

for reference, the headlight switch has three positions; off, first (middle) and second (fully pulled out). When the headlight switch is in middle position, the marker lights should be on and the fog lights should be available if you pull the fog light switch. In the second (fully out) position, marker lights, headlights and instrument lights should be on and fog lights available. When everything is working according to design, when headlights are on and fog lights on, fog lights are only on when headlights are on low beam. Fog lights turn off automatically when headlights are switch to highbeam.

upon reassembly, high/low beams and turn signals worked fine. However, I soon noticed a couple of minor electrical issues. the front and rear marker lights do not work except when the headlight switch is fully extracted (the second position). the marker lights should be on when the headlight switch is in the first and second position.

Secondly, the lights on the instrument panel are on when the headlight switch is in the first (middle) position but not when the switch is in the second position. In other words, when the headlights are on, the Instrument illumination goes out.

Lastly, the functioning of the fog lamps is reversed. In other words, the fog lamps come on when the hi beams are turned on and go off when the Low beams are switched on.

despite my best efforts, I think a wire became disconnected from the headlight switch when I removed it. don't remember which one at this point. However, Despite reviewing the wiring schematics in my Bentley manual and several pertinent posts on this forum, I can't get the matter sorted out. some of the posts are for pre-87 Porsches. earlier 911's had a different pin configuration on the headlight switch. some of the posts concern ROW vehicles that appear to involve different colored wires and wiring configurations.

wires from three sources come together at the headlight switch: that is, from the ignition switch, the turn signal switch, and the bundle of wires that seems to feed the marker lights, license plate lights, etc.. I can account for all the wires coming from the turn signal switch to the headlight switch. try as I might, I cannot account for all the wires I am seeing from the other two sources.

What I'm looking for is a simple checklist that indicates where each wire from each of these sources connects to the headlight switch.

Hope this helps.

And, disconnect the battery while troubleshooting.

Best,

Gerry





And, while you're in there, you should fuse your dash lights.










You may pm me as needed.

Good luck,

Gerry

[jayleon]

I've seen the first photo in previous posts. I'm familiar with the pin numbers on the switch (56, 58 a, etc) but what do the other numbers/letters depicted on photo 1 designate (for instance 1.5 w/s s/w)? I assume the letters designate wire colors, but I suspect they are the German abbreviations for the colors.

jay

[86 911 Targa]

Originally Posted by jayleon

I've seen the first photo in previous posts. I'm familiar with the pin numbers on the switch (56, 58 a, etc) but what do the other numbers/letters depicted on photo 1 designate (for instance 1.5 w/s s/w)? I assume the letters designate wire colors, but I suspect they are the German abbreviations for the colors.

jay

Correct.

I posted that pic a while back from my electrical library.

1. Wire size in millimeters. (1.5=1.5MM)

2. Color:

SW=BLACK
WS=WWHITE
RT=RED
GN=gREEN
GE=YELLOW
GR=GREY
BR=BROWN
BL=BLUE
LI=VIOLET

Gerry

[jayleon]

What wire, if any, goes on pin 58?

Is wiring on 86 and 87 light switches otherwise the same? if not, how do the differ. My '87 has the 9 pin switch.

your help/patience appreciated.

[JWLindsey]

Jay-

Dug out my 930 shop manual and it shows two grey wires connecting to 58 and a trio of black and white wires going to 58a.

-JWL

P.S. Looks like 86 and 87 light switch wiring is much different with different color wires and terminals.

[86 911 Targa]

Originally Posted by jayleon

What wire, if any, goes on pin 58?

Is wiring on 86 and 87 light switches otherwise the same? if not, how do the differ. My '87 has the 9 pin switch.

your help/patience appreciated.

The Bentley light switch documentation is sadly lacking several connection points on the switch.

And, I do not have the factory '87 circuit diagram.

However, because the switches are used for 84-89 3.2's you should be OK.

Here is what I would do:

Connect your switch as per the picture, which is what was documented when I replaced the the switch in our '86.

That is the actual replacement switch wiring.

Let's see if you have any "left over" wires.

If so, let me know.

Gerry

[86 911 Targa]

Here's a copy of the factory manual light switch CKT showing more (8) connection points at the switch,
than the Bentley.

I've added a few notes.

Also, the '86 turbo manual is identical.

[jayleon]

I'll give it another shot tomorrow and will advise. Makes me feel a little better to hear the Bentley manual is less than clear on the subject. Thought I was missing something in trying to piece it together from the manual.

jay

[86 911 Targa]

Originally Posted by jayleon

I'll give it another shot tomorrow and will advise. Makes me feel a little better to hear the Bentley manual is less than clear on the subject. Thought I was missing something in trying to piece it together from the manual.

jay

Athough a good guide, the Bentley is lacking in several electrical diagrams.

After you re-connect the wires to the switch, connect the meter to contact #58, and let us know it's purpose by pulling the switch to the various positions.

Also, if you have any "left over" wires.

You may pm me as needed.

Gerry

[jayleon]

turns out the headlight switch, probably original to the car, was bad. replaced it and all good. Still could not account for purpose of 1 grey wire from the bundle of light wires. However, everything works the way its supposed to.

thanks for your help.

[Cary911]

Am I to assume that what was on the k connecter now goes on the n connecter in the pictures above?

[cain]

question on the head light Switch, for Dimming, im trying to decide of my switch may be faulty as well, i have no issues except in dimming modes, When you turn the headlamp switch left, gauge lights will dim and when go right, will light up full brightness, a dimmer if you will, but

When you turn fully right, theres a little click that you have to get over, what does this far right position operate? I know that in my truck it turns on my interior roof light or dome light, nothing on my 89 3.2 comes on in this position, should it control the interior lights, by passing the door switches, etc...? Thanks cain