You can use a late model MGB light switch it has a toggle extension to it and can be found easily in the dark, still no lighted though. Over in Japan they have something similar that clips onto the original switch made from Aluminum.

Maisal/Mur, thanks.  You both make good points.  The fuse box is always a good place to start looking for electrical problems.  I'm just really happy to be able to drive at night and see my gauges!  It's interesting to note that both the rear window defogger and the emergency flasher rocker switches have small lights built into the switches, but the headlight/parking light rocker switch (the one you really need to see in the dark) has no light in the switch at all.

Like anything, the fuse box is a wear item and usually needs to be replaced after thirty or forty years. Note how it is also a terminal for multiple connections. You can extend the service life of your box by carefully noting all of the wires, removing the box, thoroughly cleaning and inspecting it, and then if it is still serviceable then carefully inspect all of the wire terminal ends and if they are good put it back together.

There are rivets in the assembly and these are often the source of frustration, though sometimes people see corrosion on the fuse holders and presume this is the issue, when it is the dissimilar metals held by the rivets that cause the problems.

Not really a Lucas Har Har Har Prince of Darkness moment but more of a small issue that once sorted will give a better appreciation for simple, mass produced wiring harnesses.

Look at the backside of the fuse box they tend to get corroded especially if a Mini has the soundproofing foam they used on the bulkhead.

I checked the continuity of the rheostat switch and found the switch terminals are shorted, but then while checking the fuse box (again) I wiggled the right side of the fuse block wiring to fuse number 4 and now the dash lights work.  Hmmm.  Oh the wonder of Lucas electrics, huh?

Yes i should have been clearer and stated they need a relay on the headlight circuit.

I guess maybe I wasn't clear about my dash light problem.  All of my lights work fine except the light(s) inside the 3 center gauges.  I know they worked before I tried to turn the frozen rheostat, and now they don't work at all.  I've been using a small flash light to check my mph, oil pressure, fuel, etc. when driving at night.  I'll short the wires at the rheostat and let you know what happens.  Thanks,

I am NOT suggesting anyone fit a relay to power the dash, running and marker lights on a mini. They are switched, fused, and sometimes also dimmed. They pull hardly any power. 

The dash lights on my 79 Clubby Estate were so dim i replaced them with some slightly higher wattage ones, no rheostat on mine though but it should be fine to by pass it with a decent relay in the system as Murray suggests.

The rheostats used to fail pretty regularly. They only dimmed the lights in the rocker switches and the heater control panel. You can hook the two wires together to bypass the switch, however the switch may be the actual short in the circuit, or it may be some issue further along, perhaps you no longer have illuminated switches or replacements have been wired incorrectly. Whatever you do, you need to first start by replacing the fuse or the fuse box so that the dash and marker lamps come back, and then ensure that you don't have a problem elsewhere.

As always, try to insulate yourself from bad advice about mini wiring. It is very simple. Find the correct wiring diagram for your car and use it to troubleshoot. Note that the headlamps wiring is NOT fused and the switch and high beam/low beam dimmer switch have a very short life expectancy if you do not fit relays to carry the actual current. The flash feature on the turn signal stalk uses the horn circuit to power the high beams for that moment, which can make for more fun if the switch has a catastrophic failure.

I haven't had much luck finding this 140-620 panel lamp rheostat switch, even on the MG/Sprite parts list sites.  They are either not available or $65+  If I'm not mistaken, when the dash lights are on full brightness (where I really need them at night), the current is virtually unrestricted through this switch, so why not simply bypass the switch completely?  Or would this create another electrical problem?  I'm wondering if an inline fuse would be in order if the switch was bypassed? 

I'm not positive, but the reostat switch may be the same as the Misget/MGB one....which are readily available.

I'll check my parts cars also.  Is yours on a little "sub-panel" down by the left knee? ...or on the steering cowl ( although I think that was only 75 )

I know this is a rather old thread, but I also need help with my dash lights.  They came on with the headlights when I first got the car (Canadian spec 78' Mini 1000) but after I tried turning the frozen dash light reostat, now they don't come on at all.  Apparently the correct reostat switches are impossible to find anymore and at night, who needs dash lights that are even slightly dimmed anyway?  The factory reostat switch has 4 electrical "prongs" on the back, but only two are used (there are only two wires that go from the dash lights to the reostat). Using a test meter, if I can find 2 of the 4 "prongs" that are shorted with little or no resistance between them, can I safely connect the two dash light wires to these prongs for the brightest dash lights possible?  Or should I just connect the two wires to the dash lights with an in-line fuse?  Suggestions?  Thanks.

Thanks for the warning. I will recheck the switch & connector. Both initially appeared in good condition.

I just re-read the thread to make certain I had good information.  Remove the rocker switch and inspect the connector it plugs into.  Inspect those terminals.  Check for continuity to the wire at the fuse block.  Redouble your testing of the switch.

You need to be careful about work-around type fixes in this situation.  If the failure is a result of a melted headlamps switch you could be continuing the issue causing the failure.

The headlamps switch sends power to that bottom fuse, if it isn't getting there, find out why.

Thanks for all the suggestions. I believe I have found the problem. Bottom part of fuse box doesn't have any power to it...with ignition on or off. Temporarily I connected those two bottom wires to the terminals at the 5 & 6 spots & the lights worked. Problem is the little pilot light & tail lights stay on when I turn the lights off. New fuse box is easy enough to install.

One side of that bottom fuse gets power from the headlamps switch.  Use a test light. Expect all of the above issues and terminals failing on the wires as well.

Check the contacts on the back of the fuse box, moisture gets in there and messes with the connections also.

Although your fuses may look good, l would replace them all right now with new ones-

Also, the fuse for the headlites may not be seated properly, use a jumper wire to see if this helps & if the fuse holder box looks crappy replace it as well-

BIG AL-