Bulb defective light is on

Robert63 · Post by **Robert63** » Sun May 25, 2025 12:44 pm

Hi All
The bulb defective light is on but all the the lights are working. However the right hand indicators are flashing rapidly but all working . Not sure where to go from here. Many thanks.

Scooba_Steve · Post by **Scooba_Steve** » Sun May 25, 2025 1:27 pm

Robert63 wrote: Sun May 25, 2025 12:44 pm Hi All
The bulb defective light is on but all the the lights are working. However the right hand indicators are flashing rapidly but all working . Not sure where to go from here. Many thanks.

What model of Z4? We need the year at a minimum.

enuff_zed · Post by **enuff_zed** » Sun May 25, 2025 2:45 pm

Check the codes.
Had one like that in a facelift and the codes said the rear led taillights had a high resistance. But they all worked? So using scanner 1.4 I coded out the checks of that light and the indicators started working properly again. No idea why though.

Pondrew · Post by **Pondrew** » Sun May 25, 2025 2:59 pm

Indicator relay flashing relies on a set resistance through the 'circuit' to flash at the required rate. If one or more bulbs in the circuit has a dodgy filament the resistance will change thus changing the flashing rate.
The bulb fault light is showing because the overall resistance in the circuit has changed, therefore it presumes a bulb is out.
Chances are one bulb will blow very soon as the resistance isn't right. You can either change all indicator bulbs on that circuit or wait for one to blow and just change that one.
If an LED has been used to replace a filament bulb, this can cause an issue (but not always. It depends on the LED resistance).

bigwinn · Post by **bigwinn** » Sun May 25, 2025 3:34 pm

Has anyone replaced the bulbs with LED lights?

Z4-forum.com

Z4-forum.com