In the pics below you'll see a single brown earth with a female connector coming off the top of the switch, you'll also see a double earth with a male spade connector on it.

Where do these connect?

I have a male spade earth on the bottom of the switch. Does the top earth loop around to the bottom? If so what is the odd male spade double go to?

Click to view attachment

Click to view attachment

Unless the wires have been molested, brown is always ground/earth.

I know the brown are earths ( i did have pics of the dismantle of the wiring but pc crash lost everything) it's the configuration of these particular earths that are confusing.

Bump for some info, would like to be safe not sorry.

Well, not much help here. I have a 4/73 car, and the riveted brown wire from the top side of the switch goes to a single brown wire into the harness. The male tab on the lower side of the switch has a single brown wire with a white tracer, also into the harness.

Prospero's wiring diagram is not very clear on the switch circuit. It only shows 1 solid brown wire. Bowlsby.net shows 1 solid brown as well.

Sorry.

Hell I'am even less help,mine been removed completely,I could see why the PO had most of the wires off as the fan contacts were trashed....way too burnt to fix.
I'am thinking that tab near you brown earth wires will be the one....could be wrong.

OK. I haven't had to trouble shoot this for myself, but looking at the switch pictures and the wiring diagram, I think I have it figured out.

The brown wire from the top of the switch provides ground for the fan windings. The tab underneath the switch provides ground for the fan indicator light. Any time the long wiper is contacting a fan speed "pad", the short wiper is grounding the tab to the light. So I believe the wire from the tab needs to go to the indicator light.

Makes sense, i will be wiring this up soon as well.

Let's see if i understand this.

The short brown wire will be earthed to the car body?

The underside tab will earth directly to the small fan indicator light?

One of the long list of removed parts includes the hot air fan that would have been in the engine bay. My guess wiring was removed by a po when whatever was done to this car in the past.

I want to verify this with a meter, but that's how I read the wiring diagram and the switch configuration. My switch assembly has two backlight bulbs (supplied with power through the black/purple wires), and a fan indicator bulb that comes on when you move the fan lever to any of the three speeds.

You do know the engine bay "booster" fan is controlled by the red lever behind the shifter, right? The switch in the dash controls the fresh air fan under the cowl.

I'm surprised nobody else has chimed in on this.