My car has a Greddy boost gauge/warning meter. Unfortunately it doesn't light up when the head lights are on... apart from once when it actually did light up randomly.

I've checked the wiring which seems fine - it's tapped into the fog light switch and the output from the control unit to the gauge shows +12v when the lights are on.

Has anyone changed the bulb in one of these gauges? I can't see any obvious was of taking it apart?

I had same prob with mine mate, brought it second hand and unknown to me it didn't light up.

Not to hard to fix thou just take her apart carefully and there is a little pcb behind dial face, just soldered couple new bulbs on from maplins cost bout 80p.

Job done !:thumb: Hope this helps.

Sounds like a common problem then.
I've undone the little bolts at the back so the gauge itself is loose inside its metal casing, but the front perspex cover refuses to budge! How did you remove it?

To take the bezel off get a small flat blade screwdriver and go round the back edge and lever it off carefully ! then just pull the needle off carefully ( again ! ) and undo the small screws on the facia, fit new bulbs, re-fit, job done !