i purchased a TF clock and oil temp gauge for my f to do blue led back light
any way read the attached how to and made a discovery that you don't need to put any resistors on the clock or oil gauge as they already have them on (i just traced the circuit with a DMM)
if you use LED'S with 30mA max current then you will be fine
so here is the proof
the 475 ohm resistor on the pcb for the original LEDs (clock)
LEDs fitted 3mm 30mA 30deg angle 3000mlcd
LEDs working on 13.5v supply
here is the oil gauge resistor
here is the LEDs fitted (same as the clock) and polarity of the LEDs
here is the LEDs fitted (same as the clock)
so there you have it just solder the LEDs the correct way round so no more fiddly fitting the resistor
hope this helps
mark