Mk1 Ignition Switch

[Champ54]

Hi fellow Stag owners,
I have had to replace the ignition switch in my early Mk1 Stag and the only switch is the Lucas 157 SA switch which is sold as a direct replacement. Clearly it is not. I know which colour wires do what function but I cannot find an accurate diagram or photo of a 157SA switch with wires connected and I cannot seem to get the connections correct. Also the original switch has 6 wires connected but none of the wiring diagrams I have found have the correct colours or what terminals they attach to. My Mk1 has the following :
white/Red to starter
white/Pink to auxiliary for radio
heavy brown to battery
heavy white to Aux + alternator
red/green side lights
red side lights
these colours are different to all circuits I can find but what I need to know is which terminals do they connect to on the Lucas 157sa replacement ignition switch. If someone has a photo showing the 157sa switch with all 6 wires correctly connected I would certainly appreciate it.

[DJT]

I take it you have seen the early wiring diagram. Hopefully someone will have the photo you want. But the Mk1 and Mk2 switches are different. It is possible to (carefully) open up a switch and clean the internal contacts.

IMG_0512.jpg



Moderator: Moved to its own topic for clarity

[Goldstar]

I’ll see if I can get a picture for you later

[trunt]

If you go to the part on the Rimmer website and click on the information logo it gives you an explanation, basically the new switch cannot accommodate the red and red green wires which are only for a one sided parking light.

OK got to my computer,, so heres what it says:-

With Lucar connections - 3 pairs and 1 single terminal

When used as a replacement for Stag MK1 (To LD20000 inc USA) Ignition Switch, to modify wiring, fit spade connectors to terminals 1, 2, 3 & 5 and transfer from original loom Brown wire to terminal 2, White & Pink to terminal 5, White to terminal 3 and White & Red to terminal 1. The remaining Red & Red/Green wires are for a sidelight functionality that prevents driving off with the sidelights only and can be insulated for safety and ignored.

[Champ54]

Thanks everyone for the assistance. The 157SA switch is definitely not a good replacement. With spade terminals fitted they dont clear the steering column shroud unless you use flag style terminals and even then they are a very tight fit. Insulated terminals just will not squeeze in as there is insufficient clearance. I ended up having to use non insulated brass flag terminals and they only just clear each other.

[Tonywhite]

I have plenty of mk1 switches if you want one