1973 3.0CS interior lights wiring

CTD

CTD

Well-Known Member
Messages
213
Reaction score
93
Location
Eksel, Belgium
Hi all,

This weekend I planned to get my interior lights working.
The car is a 1973 cs with a sunroof.
The previous owner installed a new headliner but didn't install the interior dome lights on either side of the sunroof.
Also, the switches for the door weren't there.

Now, when opening the kickpanel on the passenger side, I found one wire (brown/purple) with a connector on it, that fits my newly bought door switch. Installed it and moved to the driver's side.

Inside I found a mashed piece of something (I assume it used to be a switch) with 2 spades still attached to it. Connected to one spade were 2 brown/purple wires (together on one connector, looked factory) and on the other spade, also 2 brown/purple wires (also together on one connector).
So, 2 spades, with each of the spades having 2 wires connected to it. So 4 wires, all brown/purple.

But, I noticed that the 1 pair of the brown/purple wires are live (always, even with ignition off).

Can anyone tell me what that is? I thought the dome lights just closed circuit by grounding the wires on the door switch. How can there be a live wire on the door switch? When I take that live wire and ground it by touching the chassis, I hear a relay clicking somewhere.

Can anyone help?
 
It's live so that when you open the driver side door your window motors work, instead of only when the key is on. You have a 73, in Feb/Mar of 73 they added circuit breakers and new motors (not sardine can style). Also, be sure the black round plugs exist in the door which touch the switches, they can go missing.
 
Thank you,

But isn't it so that with this live wire, if I open the door, the live wire grounds to the chassis? Isn't that going to shortwire anything?
 
Hi CTD -- you should have a wiring diagram like this - http://www.e9coupe.com/tech/handbook/p_103.htm - in your handbook. This diagram, like mine for a 72 CS, shows power going to the dome light - part number 79 - with the door switches - parts number 74 and 75 - acting as grounds. Switch number 75 has a second connector on it for the key warning buzzer circuit. This circuit is enabled if the key is in the ignition, and grounded when the driver's door is opened.

One thing to check, however, is whether position of the dome light switch is influencing your tests. My car only has one dome light, but if the switch is in position 3 (closest to the driver), the circuit will be complete and the dome light will always be on. If your switch is in this position, the circuit may read as live at the door switch (number 75 in the diagram). I am guessing your two lights have a switch like this; find out how this switch works and make sure it is not in the always on position then test your wires again. If the dome light switch is on, and your key is in the ignition, it is possible that the clicking sound you are hearing is the key warning buzzer receiving only a very low voltage.

If you pull your handbook and use the wiring diagram key - http://www.e9coupe.com/tech/handbook/p_101.htm - you should be able to identify these parts on your car. And if you look closely, the color of the wiring is also marked in these diagrams. You actually can trace the circuit path (with a magnifying glass).
 
Sorry if off topic, but when did they come w/two dome lights?

I only have one (LHD) on the driver's side.
 
teahead said:
Sorry if off topic, but when did they come w/two dome lights?

I only have one (LHD) on the driver's side.
Click to expand...
i was wondering the same thing ... although i don't have a sunroof ... so i wasn't sure. this is kind of like the e30 m3 approach - a light above each door.
 
WIRING Model (1).jpg
HERE
SINGLE light yet the same also one wire goes to activate the door relay so the lights work with the door open
 
that's why i like the electrical diagrams that are focused - like the one on lighting, the one on comfort equipment, engine electrical, etc.
 
Thanks everyone,

I figured it out. Now I just need to source the part (switch with 2 connectors).
 
i guess its a USA thing. keep dumb 'mericans from locking keys in the car. most people unplugged them.
 
Yeah, someone should compile a list of the DOT requirements on our cars so we can reverse them. If its good enough for the Germans, its good enough for me.
 
You must log in or register to reply here.
Back
Top