This week's tiresome repair - with pics and a tip for any other TX4 users.
While prepping my 2016 TX4 for its plate a few weeks back, I found both bulbs in the taxi roof sign were out. Replaced them and one was out again within a week. Took a closer look at the harness and didn't like it muchly:
^ Scorch damage in the sockets and at the plug connector, also not sure why there's tape around the wiring
Got a replacement harness on fleabay which worked but wouldn't fit the bracket. That's because (as I now know) there's more than one type:
Later type is on the left, earlier type on the right. The white plug connectors are identical and both take 382 P21W bulbs, but
the lock tabs on the sockets are different. Thankfully T&S in Liverpool had the later type.
Job done and so far so good. However, I'm not impressed by the build quality of this later TX4 - various electrical gremlins like this and a bunch of squeaks/rattles I'm still working through.