Fiat Grande Punto – Number plate lights

number plate bulb comparison

One of the first steps of freshening up the general look of these cars, is their lights. The yellow bulbs both inside and out, have to go. Some crisp white LED’s are generally the way to do, but don’t be fooled by plenty of such bulbs claiming to be CANBUS-error free, as most are not.

CANBUS?

Controller Area Network bus (CANBUS), is the computer system that connects various electronic parts of your car together. Most of this isn’t particularly fancy, as far as the lighting system goes, it’s generally “I’ve sent out x amps/volts to this light, I should get y back”. So when you start changing bulbs, that may vary from the stock ampages, you will receive a CANBUS error on your dash. This might result in just a dashboard light/warning, and/or the device not performing as you’d expect – my first straight LED install for example appeared fine at first, but the bulbs started flickering erratically.

My solution

I initially stuck some LED’s in, and as mentioned, whilst there was no error on the dash, and all appeared fine, I did eventually realise they were flickering like mad, and would’ve been sure to attract some unwanted attention. As with the headlights when installing LED’s (although you shouldn’t do this), the solution is to add a resistor. Resistors reduce the current (usually resulting in them heating up), so the bulb and CANBUS continue to operate as normal. I purchased the following from Halfords, which plug straight into the number plate bulb holders, then the new LED’s plug into them, resulting in fully functioning bulbs, and no errors.

Click to view item

Is this the only solution? Of course not, if you’re comfortable with some electrical work, there’s nothing stopping you from adding a suitable resistor, or you might just be really lucky and get some LED’s that actually work whilst not triggering any errors.

Instructions

Full instructions for changing rear number plate light bulbs

  1. Remove number plate light

    At each end of the 2 bulb holders, is a clip. Press it and pull the edge, removing the holder.

  2. Remove bulb holder

    Turn bulb holder anti-clockwise and pull it from the light unit.

  3. Remove bulb

    These bulbs (501/W5W), just pull straight out.

  4. If using my solution (otherwise skip to #5)

    Plug one of the resistor fittings into each of the bulb holders

  5. Install new bulb

    Plug your new LED into the resistor kit’s bulb holder, or the original if not skipping step 4.

  6. Finish up

    You might want to give the light holders themselves a good clean or something at this point to get the full benefit; otherwise, push the bulb holder back into the light fitting and turn clockwise, before tucking the cable up into the hole and reinstalling the light fitting.
    number plate bulb comparison

    The effect when seen versus previous is obvious, a much crisper, clearer light.