Donor instrument cluster must've been from an RT/LT, I imagine?

Not necessarily. Two easy ways to tell:

1. Duel warning lights are both marked on the instrument face with a fuel symbol
2. Later clusters have no pin 8

But if you do have pin 8 and only a single fuel symbol on the plate, someone has done a sneaky and changed the plate for a later one... If (1) then it's just the bulb holder missing.

Dai wrote:Not necessarily. Two easy ways to tell:

1. Duel warning lights are both marked on the instrument face with a fuel symbol
2. Later clusters have no pin 8

But if you do have pin 8 and only a single fuel symbol on the plate, someone has done a sneaky and changed the plate for a later one... If (1) then it's just the bulb holder missing.

Thanks that's helpful Dai--there is a pin 8 and both lights are on the face so hopefully replacing the bulb will fix it.

Funny thing is, I'd done the variable resistor hack on the low fuel circuit a while back.  Now I get to find out if I did it right.  

I did finesse that hack a bit but can't remember - nor find - if I updated it here. From day (night?) one I've really disliked the LCD clock because I found the illumination to be too low.

- I mounted a standard 52mm clock in the fairing (cut the hole out in the small fairing section where the later RS has the speakers)
- I pinged out the red/white wire from pin 1 of the instrument connectors and re-routed it to the new clock, along with an earth and a grey/white wire from the pilot light for the clock bulb
- soldered a 7/0.2mm wire from the original clock positive feed pin to the input site of the original hack
- used the now-vacated pin 1 socket in the instrument connectors to carry the switched dim/bright feed to the fuel LEDs.

It just tidied it all up.