problems changing cabin flourescent tube for led lighting

[hogggman]

hi all.the flourescent tube in the ceiling light in my bongo is rather 'tired'.it will only come on at full brightness if the engine is running first.i purchased an led board intending to fit it into the rear ceiling light.the led came with various common connections,but nothing to connect directly to the existing tube connections.so,i removed the light fitting to find a 12v supply to connect the led to,and wherever i metered it gave me a strange reading.any ideas or suggestions?thankyou.jamie

[Simon Jones]

You'll probably find its putting out about 100 volts AC, so your LEDs wont, like it! There is an inverter inside the lamp housing to fire up the fluorescent tube, so you are very unlikely to find a direct replacement, so will need to mod the light to get to the 12 volt DC supply. Don't have the colour codes to hand, but I expect there will be 2 wires plus an earth.

[jaylee]

One live & 2 earths..? One switched to the door pin. (On when opened) & the other earth wire switched to chassis... (For when the door is shut & you want it on.) Well, it is on a tintop!

[Simon Jones]

Yep, that's what I was thinking . Same as the interior light at the front of the cab.

[jaylee]

I would be tempted to cut the live feed to the lamp housing just after the white connector block & run it to the live on the LED, that would cut out any "inverter"...? Then use the negative terminal to the 3 position switch to run the LED to ground..?

My memories bad on the strip lamp.. It's a while since i got in there & fixed it.

Do you have a volt meter..?

[g8dhe]

The part labelled I3-04 is the light in question;

The Blue/Red wire is the +12volts, the Black is earth and the Red/Green is the door switched earth, the colours refer to the ones in the LOOM not those within the light itself, they vary!