wobbly voltage, wobbly idle and also my speedo & rev counter don't light up
 

hello chaps.
car is v2 sti ra with power fc, decat and so on. mapped by jgm last year with same mods

so yeah, problem 1 is the wobbly voltage. when warm the voltage often starts to fluctuate between 12.3 and 13.6 according to my hand commander thingy. it makes the headlights (probably tail lights too) dim and the dccd light follows along.
my dad suggested an earth but that doesn't mean a lot when you have no idea where these things get earthed.

i also have a wobbly idle when warm - it fluctuates between 830-960rpm . not necessarily connected to the voltage as that happens when im not idling. idle control valve looks clean according to Tim farmer so im open to suggestions on that one.


other problem is that my speedo/rev counter stopped illuminating. the brightness control fuse had popped but I've replaced that and they still don't light up (brightness control is functional now though- dccd light changes when headlights come on)

im guessing the bulbs have popped - how does one replace them and which bulbs do i want?


thanks chaps :)