[redman]

I have Fault 21 showing on my display, which is an issue with the passenger side tail lights. I have replaced the bulbs in both the car body cluster and the boot cluster as suggested in other posts I have found, but I am still having the issue.

I am guessing I have a faulty wire somewhere, as either both lights work on the left hand side, or neither lights work. They are very intermittent.

Has anyone got some easy-fix suggestions to try before I bite the bullet and send it into the garage tomorrow?

Many thanks,

Hi
Is your left hand front sidelight affected? as it is fed from the same positive wire. According to the wiring diagram I have, both left hand clusters have different earth points so unlikely to be that.
Make sure there is no corrosion on the terminals of the light units and their associated connector. Are the bulbs a good snug fit?

 

[redman]

Glad you have it sorted now and
hope the garage didn't charge you too much to fix it. Thanks for updating your post

 

[redman]

I have 2017 Astra 1400 turbo . . Have fault on drivers side braking light and indicator lights . when turning right the front indicator bulb flashes very rapidly .changed braking and indicator bulbs , a. ps dash board lights come on and off intermittently..Very gratefull for guidance on this request .John booth

I am assuming you have an astra k with it being a 17plate.
This is a known fault on the astra k rear lights. It is the plug and the ground centre pin on the light that tends to burn out. Try unplugging it and have a look.

Vauxhall are covering the repair under a
5 years or 100,000 mls tsb

your front indicator is flashing faster because your rear bulb is not powering up due to this fault.