Head Light Wiring

[l_turn9]

Hi Gang,
My head lights have stopped working and I have traced the problem to the back of the head light switch. Most of the wires are hooked up but it appears one or 2 wires have slipped off of their spade/s. I am trying to interpret the 1978 Flow Diagram (with little success) and will head to the 1973 Wiring diagram posted by PelicanParts after I send this.. What I am looking for is a list of the wiring colors that go to each spade on the HL switch. I plan to look carefully at the switch as I expect it to have numbers or letters on each spade (I hope) - or at least some indication to orientation of the wires on the switch.

I would think someone out there has a note pad with a list of the wires with their colors and a way to know where to connect each one.

TIA!!
LarryT
1974 911
PCA Member since 1999

[RAW911]

Check this Thread: Headlight switch wire ing help)

[javadog]

The terminal designations should be visible on the body of the connector, next to the spade terminals. Let me know which color wires you need to find a home for.

JR

[donporfi]

Found this picture here at the forum

[l_turn9]

Thanks for all the great answers - I think I am on my way to solving my problem. I used the info provided to come up with the table below which may help someone in the future. I got some of the color abbreviations from a Mercedes reference I have.
There are 4 wires FROM TS:
FROM TURNSIGNAL
#1 - RT/WS RED/WHITE - fits to 75,
#2 - GR/SW GREY/BLACK & GR/SW, 2 WIRES fits to 58L,
#3 - GR/RT GREY/RED FITS to a separate plug from the switch,
#4 - WS/SW WHITE/BLACK fits to 56.
`
TERMINALS ON THE HEADLIGHT SWITCH:
MOVING CCW, STARTING IN NOTCH WITH:
56 - WS/SW WHITE/BLACK. (From TS).
K - GR GREY & GR/GE GREY/YELLOW (2 WIRES)
58L - GR/SW GREY/BLACK & GREY/BLACK FROM TS
58R - GR/RT GREY/RED (2 WIRES)
75 - RT/WS RED/WHITE (DOUBLE TERMINAL)
57 - WS/GN WHITE/GREEN
58A - BL/SW & SW/BL, BLUE/BLACK, BLACK/BLUE (2 WIRES)
30 - RED (12V FROM IGN.) (DOUBLE TERMINAL)

WIRE COLOR LEGEND:
SW=BLACK
GR=GREY
WS=WHITE
RT=RED
GE=YELLOW
GN=GREEN
BL=BLUE

[l_turn9]

OK Gang, I had hoped my problems would be over after matching the switch and term #s to the info about the wires that go to each! I am going to review my info again but here's my problem. It appears a PO has modified the wiring - probably when installing a stereo. There is one wire hanging that MAY have been attached somewhere previously. It is a factory wire that exits a wire cover with a Yellow wire that disappears behind the dash. It is blue/Black which goes to a female spade connector. Then a black/red wire about 4" long comes out of that female spade connector and ends in another female connector. Next, term #75 is supposed to have red/white double terminal and #30 is supposed to have a Red double Term with at least one wire coming from the ignition. I moved a red from 75 and put it on 30 with the other large red wire. The Red/white that was on 30, I moved to #75 per instructions. Now, I have 1 empty spade on 56 that has a black/white wire coming from the turn signal switch on the other spade.
As I said, I am going back and double check all the connections to the back of the switch to confirm them before I attach 12V. My primary question at this point is will there be a problem attaching 2 large red wires to #30. The instructions indicate this is correct and logically I can imagine having 2 "hot" wires on the same terminal causing a problem - anyone disagree/agree?
I know troubleshooting wiring problems by long distance is a terrible way to do things but any help you can offer will be appreciated.
TIA!
Larry

[javadog]

This is what the factory diagram shows for a '78:

30 RED, RED/WHITE
75 RED/WHITE
56 WHITE/BLACK
57 WHITE/GREEN
K GREY
L GREY/BLACK
58L GREY/BLACK
58R GREY/RED
R GREY/RED
58A BLACK/BLUE, BLACK/BLUE, RED/BLACK

[l_turn9]

Thanks! I'll print your reply and crawl back under the dash to compare your notes to my switch. I really appreciate you taking the time to write those wiring details down for me!

Thanks again -
LarryT
74 911

[javadog]

When I initially read your post, I thought you were working on a '78. Looking more closely, it looks like you are working on a '74, which has one change from a '78. This is what the factory diagram shows for a '74:

30 RED, RED/WHITE
75 RED
56 WHITE/BLACK
57 WHITE/GREEN
K GREY
L GREY/BLACK
58L GREY/BLACK
58R GREY/RED
R GREY/RED
58A BLACK/BLUE, BLACK/BLUE, RED/BLACK[/QUOTE]

[l_turn9]

Thanks for the update! Yes, it is a 74 and I really appreciate your efforts. It looks like the difference is Term 75 went from Red/White to Red. I'm heading to the garage shortly ;-)

[l_turn9]

Man! I have learned more about headlight switches and turn signal switches that I ever wanted to know!! I have triple checked the wires at both ends using the Flow dia. for 1974 (which I now know how to read) ;-) and everything is correct (well I guess it can't really be correct) - I also tried a different HL Switch and a different TS Switch with no changes.
So here's where I am. I have one side of a piggy-back terminal at #56 empty. The other side has a White/Black wire is from the TS Switch. There is a "Spur" wire off of the cable from the TS switch that ends up going to the Relay. The TS Cable has One empty "spur" wire that is light Grey of White - not connected. The only wire I see that is not connected is Black w/Blue Wire from a relay that also has a empty Black w/Red wire not connected. There is a similar Black w/Blue and a Black w/Red - both are not connected. The other end of these cables disappear in a cable run under the Fan Blower controls. And finally the horn blows when 12V is connected. The car starts and runs normally.
I have a Flow Diagram for 1974 and a Wire diagram also for 1974 but not color. All documents agree as do the excellent info from you guys! If anyone can think of something i might be doing wrong please let me know. PS there's a remote possibility I swapped the plugs going into relays (there are 2 side by side). But even if I did, those remotes are all the same right?
One more thing, There's a wire from the emergency Push Button that has a resistor in the wire and the WD shows it connecting to 58A but there is already a piggy back that is full on 58A. Can it goes elsewhere? I found the wire was brittle & broke a while back and things have been operating with out a connection for a long time. Maybe I should leave it off?
Help?
Larry
74 911

[SpyderMike]

Larry,

Honestly, I find it hard to follow what you are saying.

Let me try to answer what I think you are asking:

Having one wire at terminal 56 is okay - it should be a White/Black wire.

The Black/Blue smaller gauge wires are for the gauge lights from terminal 58a. They seem to daisy chain to the different gauges. You will see them all behind the dash.

I am totally baffled by these statements:

Originally Posted by l_turn9

There is a "Spur" wire off of the cable from the TS switch that ends up going to the Relay. The TS Cable has One empty "spur" wire that is light Grey of White - not connected. The only wire I see that is not connected is Black w/Blue Wire from a relay that also has a empty Black w/Red wire not connected. There is a similar Black w/Blue and a Black w/Red - both are not connected.

Can you be more specific? You have a "spur" wire of what color coming off the TS switch loom just under the dash? If so, then what color is that wire? Is it the Gray or White one in the next sentence, or is that a different wire?

The black/blue and black/red you mention as additional unconnected. You list these twice - are you talking about the same thing or you see two pairs both unconnected? Where are these seen (under the dash or near the relay)?

If you don't like the horn, then for now, you can pull the fuse. The horn relay is getting power. It is a switched ground wire that activates that relay.

Trying to help,
Mike

[SpyderMike]

Looking at the horn issue, and at a 1973 schematic, the ground at the relay which activates the horn is a brown/white wire at relay pin 85. That wire connects to the "flasher, dimmer, wiper/washer switch with horn ring on steering column" pin 82a. From there, a brown wire exits the steering column switch assy from pin 31 to a chassis ground point.

If that brown/white wire or the brown wire are grounded anywhere then the horn goes.

Mike

[timmy2]

1974 color schematics.
https://www.dropbox.com/sh/s292jtsyvl6llw2/AABF-ofgMfoMltGa99Asphr5a?dl=0

[l_turn9]

Thanks for the '74 Flow diag!! I will study it....

[RSTarga]

Disconnect your battery when working on the switch

[SpyderMike]

Come to think of it - your black/blue and black/red might be loose from the dash panel potentiometer that dims the dash bulbs. Check out connection 58a on E20 on page 4 of the schematic you just got the link to.

[l_turn9]

Hi Mike, thanks for reading my poor explanation of where I am. Let me try to explain a bit better.
I said "There is a "Spur" wire off of the cable from the TS switch that ends up going to the Relay. The TS Cable has One empty "spur" wire that is light Grey of White - not connected. The only wire I see that is not connected is Black w/Blue Wire from a relay that also has a empty Black w/Red wire not connected. There is a similar Black w/Blue and a Black w/Red - both are not connected."
As you know the harness from the TS switch has 2 cables. One goes to the Relay and the other goes to the HL Switch. About 1/2 way down the cable from the TS Switch in the cable that eventually goes to the relay - what I call the spur is a short piece of wire about 5" sticking out of the cable cover. I believe this has been a empty connector as long as I have owned the car. the spur is either Gray or white.
The unconnected wire (Photo) is hanging behind the dash coming from a Relay Plug. There is a female connector on the end of the Blue/Black wire. Attached to this Female Connector is a short piece or Red/Black wire (4" long) that has another female connector. This wire is also not connected. Based on the colors I believe it is more Gauge Light wiring but cannot find where it is supposed to connect.
The other comment you questioned was: The black/blue and black/red you mention as additional unconnected. You list these twice - are you talking about the same thing or you see two pairs both unconnected? Where are these seen (under the dash or near the relay)?
This is a twin to the previous blue/black wire. But this one has the blue/black part connected to 58A. The red/black piece of wire is also not connected on this twin wire..
re: horn -- Yes I agree - I pulled the Horn Relay. I mentioned it hoping it might provide a clue to my problem.
Thanks again for your help with this frustrating problem! I know this is a difficult way to troubleshoot electrical problems - I have trouble keeping track of what i have told ya'll!
LarryT 911

[SpyderMike]

You will get there Larry.

There is a dimmer pot on the dash to dim the lights. Check out connection 58a on E20 on page 4 of the schematic you just got the link to. Here is a cropped image:



The black/blue with attached black/red connection would go on the pot. The black/red connection attaches to a ground wire through the resistor (N6) off of the Emergency Flasher switch (E3). On my later car, my wire from the resistor was not brown by white or light grey, but the resistor was real close so it was easy to tell that was the wire.

[SpyderMike]

Using page 3 of the schematic, you see there is an unused white wire near the section for the turn signals. This could be the unconnected spur wire you refer to.