Granada traditionally covered North East Wales though don't think they do officially anymore. Can generally pick up Central, Wales and Granada around this area and generally speaking Birmingham, Cardiff and Manchester are all as irrelevant as each other.
I think Wrexham is still on the weather map, and they always used to feature them in regional football shows, not that they do any anymore. As you say, Wrexham was on the cusp of three regions, and HTV Wales was by far the least watched in our school. We had Granada, as did most people we knew, and I was most impressed when I went to Craig Leedham's house after school one day and he had Central. We all had all three tuned in to the telly and on League Cup nights on a couple of occasions I'd flick between the three to see who was covering which match. And all shops had three different versions of the Radio Times (which is useful for me as when I go to see my parents I can still pick up a London/Midlands one to use at home).
Actually I think Granada specifically covered Wrexham more than BBC North West, who never did, because for many years the Wrexham-Rhos transmitter only had space for two channels, which were BBC1 Wales and S4C. That was why Chesterfield vs Wrexham in the FA Cup in 1997 had to go out on BBC1 Wales, in an era when all other Welsh football coverage was normally on BBC2, as it was so hard to pick up BBC2 Wales in Wrexham. So you could get BBC1 Wales easier than HTV.
It's always been said that the capital of North Wales is Liverpool and I would absolutely go along with that, we spent far more time in Chester and Liverpool growing up than in South Wales (and as mentioned up there, most Wrexham people sound like Scousers). I've only actually been to Cardiff twice in my entire life.
Inspector Sands and Brekkie gave kudos