On my 2017 FFE, both caps are black. The low pressure port is closer to the front and the tube that rises up to it is thinner than the tube rising up to the high pressure cap. However, the line that the low pressure tube connects to is thicker than the one that the high pressure cap's tube connects to. See here:
If you have Forscan, you can read the pressure for BOTH the high and low sides of the A/C system. The technician at the dealership where I was having work done was surprised that there was both on the FFE. Apparently, most vehicles only have a sensor on the high pressure side, and that includes my wife's new F150 Lightning (I just had to see what Forscan could tell me about it!).
As for my issue, everything is back to normal now that I've had the evaporator replaced. The dealership managed to cut the price by a few hundred dollars from the estimate. Still a pretty penny that I could have avoided if I realized the 6-year extended warranty I purchased with the vehicle only had 100,000 km on it, unlike my last vehicle that had 150,000 (we made sure the lightning has 150,000 km coverage!),
At least I got 39,776 FordPass points for the work to use towards something. It was just short of the 40k points for buying the Lightning. :roll: