I'm having issues with my 2013 f150 xlt. I think one issue may be the fuse, Fuse 27 I think. Its running rough at the lights, sometimes not turning over(usually once a day-then fine the rest of the day) so I have to hit the gas to turn it over sometimes. Not sure why my wipers aren't working. A dealership here fixed them, said they were on backwards($300), later they're out again. Should I get a Ford diagnostic test or just get a mechanic to look my truck over? I think they charge around $250 for the test here in SC. I'm plan to call in the morning.

 

For the wipers, I'd go ask what they did - and tell them that they quit again. At the very least you should get them to explain what they mean by the wipers were backwards.
If they're talking about the blades, that seems to be impossible. If they're talking about anything else - why did they work for a while before you brought it to them. (unless you changed something).

As far as diagnostics, you need to know what you're getting. Justifying troubleshooting time is a big issue - and dealer time is very expensive. But, are they just saying that they will check it for 2 hours or so and tell you if they found anything? If it was me, I'd really like to know what I was getting for my money. Probably they have a list of tests and they will do that list- and if they don't come up with anything, well too bad.

Finding an independent mechanic might be better, but it's hard to know if they can really do any better. Some can, but it's hard to know who they are. Get recommendations if you can, Then go talk to them and ask what they will do to figure it out. Stuff that isn't screaming " I'm broke" can be a bitch.

Can't tell you what to do - sorry

HJ