If you decide to take the headlight switch apart I suggest you do that inside a 1 gallon ziploc bag. There are spring loaded parts inside that will spring out when it is opened. So open SLOWLY so you can see inside what goes where. As stated the contacts inside like to get burned that need cleaning.

Check your toggle switches, they are known to have wear inside and carbon build up which can cause the connection to not work.

Take it apart, sand it down a little so its clean, reassemble and see if that fixes the problem.

According to Haynes' 89-onward wiring diagram, your car should have a "dim-dip relay". No idea how it works.

From the battery terminal on the starter solenoid, a brown wire (always live) goes to the lighting switch [49] in the dash rail. It has 2 output wires, a blue one that goes to the relay and a red one that eventually also goes to the relay. In between, the red wire goes to a fuse in the fusebox, [terminals 7, input and 8 protected side] From the protected side of that fuse a red wire/green trace feeds instrument lights, side marker lights and license plate lights.

So, the blue wire feeds the dim/dip relay from the switch. It may be a control for the relay - don't know.

The dim/dip relay also receives unswitched power via a brow/orange trace wire from an on-line fuse fed by a brown wire from the solenoid battery terminal - always live unless the fuse is blown. Between the fuse and the dim/dip relay is a "dim/dip resistor". Don't know what that does either.

The dim/dip relay feeds the "dip beams" AKA low beams, via blue/red trace wires, nothing else.

The main (high) beams are fed two ways. When you flash the high beams, a switch [56], fed by a purple wire from the fusebox [fuse 3-4, always live] and is connected  by a purple wire directly to the main beam circuit Blue/white trace wires. The horn works off this same circuit, so if it works, the fuse is good.

So if you pull the flash switch stalk. the high beams should light up. That should work even with the engine and everything else switched off.

The high/low switch [50] doesn't make sense to me the way it is drawn, but it seems to suggest that if it is set to main(high) beam, it should light up the high beams while telling the dim/dip relay to shut off the low beams.

Does your mini have fusible links? I know you state it's an '89 but ... The links are located by the starter motor. Later minis have the headlights fused.

Hello All !
I have had a few classic Mini's, my first race car was a 1962 still racing with VARA and Bart Smith, GO BART!

I finally imported a 1989 Mini from the UK and have been fixing it up, many Minimania parts of course, but all the lights including the flashers work EXCEPT the headlights, flip the toggle down and n-o-t-h-i-n-g.........
H-E-L-P.........don't believe that has to do with fuses?  
Any help would be appreciated, now up in the Northwest in the State of Washington....
thanks 
Rick