Changing bulbs

[Slokie]

It all started when I came to change an interior bulb. When looking on ebay, I came across a whole new world of L E D alternatives.Could somebody please explain what "CanBus" is, as some bulbs are marked canbus.

[stevestrat]

In it's simplest terms, canbus is a communication system within a car's electronics, allows sensors, motors, actuators etc to communicate with the relevant ecu.

LED bulbs that are used externally on a 75 or ZT, indicator, side, tail, numberplate, headlight, basically any bulb that is monitored by the diagnostics, have to be canbus compliant or they will cause an error and trigger the bulb failure warning light.

[Slokie]

Thanks for that steve, does that mean every bulb I use in my MG has to be canbus compliant.

[chris_h]

The monitoring system detects that a bulb has failed by measuring the current draw. All none low energy bulbs will draw enough current so that they will not be detected as failed when they are on. However low energy led bulbs have very low current draw and so even when they are working correctly they can be detected as failed. Can bus compliant bulbs have an extra resistor to draw extra current and will not be detected as failed.

[stevestrat]

Doesn't apply to interior bulbs and the ZT does suit the blueish white LEDs for the interior lights, that's what I've got in mine, dirt cheap as well, I got a pack of ten for under £2 on Ebay! also I have LED sidelights, canbus compliant of course, because they are brighter than standard bulbs.

The only exterior bulbs I've heard aren't covered by the diagnostics are the indicator side repeaters, fog lights (front & rear) & reversing lights I'm not sure about (never had one blow!), maybe somebody else could advise about them or just pull a bulb and see if the bulb failure light comes up when you switch them on?

[suzublu]

Doesn't apply to interior bulbs and the ZT does suit the blueish white LEDs for the interior lights, that's what I've got in mine, dirt cheap as well, I got a pack of ten for under £2 on Ebay! also I have LED sidelights, canbus compliant of course, because they are brighter than standard bulbs.

The only exterior bulbs I've heard aren't covered by the diagnostics are the indicator side repeaters, fog lights (front & rear) & reversing lights I'm not sure about (never had one blow!), maybe somebody else could advise about them or just pull a bulb and see if the bulb failure light comes up when you switch them on?

You're right Steve,all you mentioned can be fitted with led's without triggering the bulb out warning,i've done them all ;):D