Back light bulbs on a OBC

[keith52]

Just replaced mine and was pleased with myself on how easy i found it to do without pulling the dash apart but when i turn the h/lights on the display lights disappear great in daylight but invisible in the dark Anyone !!

[Simon]

Obvious question now....but have you turned the dimmer down?

[keith52]

Should have put that in my post , yes Simon tried that no difference although in daylight hours with the lights on you can see a dimming of the backlight. I wonder if by resoldering i've damaged the circuit board ? hope not means i'll have to fork out the Ԛ£20 + to Trainers Cheers keith

[Brianmoooore]

Don't see how you could cause this by damage to the backlight circuit board.
Sounds like somehow you are feeding the 12V night illumination supply to the earth connection of the backlight.
Check the plugs are in properly is the only suggestion I can come up with at the moment.

[keith52]

Was working correctly before the bulbs failed and i only removed the bulb holder replaced bulbs and refitted In daylight the display fades slightly without the lights on when i operate the dimmer switch so maybe a fault there on the switch although i thought i was a resistor

[smithy318i]

it is a resistor.

You did put 6 volt bulbs in didn't you!

[keith52]

5 volt from Maplin, if too small a voltage i would imagine they'd blow ! although the guy there was as cluless as me

[Brianmoooore]

5 volts is correct.
Check the earth connections for the OBC. Can't remember where they go, but should be brown wires.