I have a 1390 and recently picked up a 1390T for the wife.
My question is are they the same unit with just a different cord or are they completely different?
Are the cords interchangeable cause the T model cord is a lot thicker than the basics 1390 one.
Yes, 100% same units except power cord. In fact if you look at the model number on both the units, it will be 1390. As clearly described on Google (see product description of 1390T), it's only the cord that makes the difference.
My 1390T has a separate cord for the traffic receiver. A Garmin dealer in Melbourne Aust told me it will give traffic updates even without the traffic receiver cord plugged in due to the strong FM signal in the city.
Recently had the traffic ahead alert on a major freeway. I took the detour option (supposed to be 30min quicker) but as the Garmin calcs the time using road speed limits etc & as there was a lot of traffic on the alternate route, by the time I rejoined the freeway I recognised the traffic I was with before taking the detour. Nice try but sometimes technology can't be a crystal ball.