Technical 2019 lounge 1.2 Drivers door speaker isnt working

[Mark471]

Hi all, new to the forum.
My drivers door speaker stopped working a few months ago after being intermittent for a bit. The tweeter is still working though.
Ive recently installed an Xtrons head unit and all seems to be ok with that, at least the passenger side door and tweeter work fine along with my drivers' side .
I bought a set of Alpine speakers (front and rear) and was going to fit the fronts (for now) at the weekend, so imagine my disappointment when after the euphoria of removing the drivers door panel and temporarily plugging in my nice shiny new alpine speaker to find it is still kaput on that side with no sound from the 6.5" unit but playing on the tweeter.
I havent got into diagnosing any fault yet, just wanted to know if anyone has suggestions after a similar issue?
My first point of call will be to unplug on the back of the head unit and test resistance across the FR +/- terminals (and I'll compare with FL+/- readings for reference) , but looking for suggestions where any potential wiring breaks could be so i can investigate further if it proves to be open circuit?
For info it was the 5"UConnect unit fitted as standard - Dont think any rear speakers fitted as standard, but have some now to fit after I fettle this front speaker issue

Thanks in advance guys.

 

[John202020]

Was it intermittent before replacing the head unit?
I doubt Fiat would use a dividing network so check the continuity between the door wires( each one) and the rear plug when it's removed from the rear of the radio, also check accoss the lead to the speakers don't be surprised if it's almost open circuit( even though the tweeter works ) now short together the door speaker wires, any change?
This problem has been reported once before many years ago can't remember the outcome