Ignition switch wiring
 

Another electrical issue... sigh.

Before I removed my dash I made note of all the connections on the ignition switch... or so I thought!

My lights only work with the ignition off (not ideal). Everything else appears to be working correctly.

Does anyone have information/a diagram of the wire colours and the terminal numbers on the switch?

Any help would be appreciated.

Car is a 1970 with the ignition on the steering column rather than the dash.

Faust;

Late 122 /123 Wiring Diagram: http://www.sw-em.com/123GT-Wiring-Diagram_Euro.jpg See Ign Sw at Item 52

Headlights are not supplied by Ignition Power, they are supplied by Black wire, connected to Battery Power terminal (30). If you were to connect that wire to term 54, Lights current would run through Ign Sw contacts...not recommended!

If you want to make a change, to make lights an Ign Sw controlled function, you must install an Ign Slave Relay. See: http://www.sw-em.com/Ignition_Slave_Relay.htm

Cheers

Cheers Ron.

I'd got the idea in my head that the lights were not controlled via the ignition - you can have them off with no key in the slot - but it strikes me as very odd that they only work (including the high beam flash) with the ignition in the 'off' position.

I'm gonna have to re-think this one!

Faust;

In the original wiring, Lights work anytime you turn ON switch, and current does not run through Ign Sw, but that means you need to remember to turn them OFF after leaving vehicle or you will have a flat Battery tomorrow...a Lights-On Reminder Beeper is an option.

See: http://www.sw-em.com/electrical_upgr...eminder_beeper

Cheers

Ron,

Think we're making the same point from opposite ends! (I've probably not explained the problem very well).

The lights are independent of the ignition switch as you say. Ignition off or on has no bearing on the operation of the lights.

Right?

BUT

The lights will only work with the ignition OFF.

If I turn the lights on with the ignition ON, they don't work.

This is the problem.

I didn't disconnect the light (or fan & wiper) switches when I removed the dash (just supported them so the connections didn't get damaged).

The ONLY thing I disconnected was the ignition and indicator switches - these all work 100%.

I'll have a poke around under the dash and see what I can find.

Faust;

Now I understand the question...!

"Ignition off or on has no bearing on the operation of the lights. Right?" Answer: Right!

"The lights will only work with the ignition OFF. If I turn the lights on with the ignition ON, they don't work."
Answer: (...and Ign Sw is the only thing which has been touched...!) I have trouble coming up with an explanation for this action...it sounds like the Light Switch power (Black wire which should be going to term 30 on Ign Sw) is now coming from a point which is powered when Ign is OFF and not powered when Ign is ON, and there is no such point on the Ign Sw that I can think of...the only thing I might suggest is that you inadvertently misconnected the Black (Light Switch Supply) to some wrong point resulting in this action...I have no specific answer but suggest you concentrate your efforts on that Black wire supplying the Light Sw, and inspect and verify wiring of Ign Sw against Wiring Diag and color codes given.

Let us know what you find!

Good Hunting!

Cheers Ron! Knew we'd get there in the end... :thumbs_up:

I'll have a look at the wiring this weekend and let you know how I get on - I'll wait for my new overdrive switch to arrive first though so I can mount it on the steering column shroud at the same time - might as well kill two birds with one stone.

Mike

Hi Mike, found this while clearing out a box of bits, may give you a clue.
Regards
Andy.

Thanks Andy... that will help me a lot when I have a look at the connections.

Nice one!

In case this is still of assistance, here are a pic and notes I made 6 years ago. (Ignore the “push-button switch” in drawing - not original.)

The red lines on left hand side of the drawing indicate the internal connection between the various terminals in the different positions of the switch.