The light in my glovebox doesn't work and I have even changed the bulb.

Any ideas as to why is this as all other interior lights work.

Probably the switch itself. You need a voltmeter to check if 12V is getting to the switch, and also to the other side of the switch when the switch is closed. Red wire with black stripe IIRC.

If it's not that, it's likely to be wiring to the under dash voltage control unit.

Isn't it wired into the sidelight circuit?, so it only works when the lights are on.

Isn't it wired into the sidelight circuit?, so it only works when the lights are on.

No it even works with ignition off.