Okay ;
You just asked a really good and important question because turn signals and brake lights are often combined and it seems few use the turn signals anymore but I digress......
First and foremost : are you going to use the brake lamps as turn signals too ? .
Then you'll need a
6 wire typ of switch, there are millions of them out there, most of the new ones are made of Chinesium and guess where ? .
Samples, scroll down to see the ones that won't make your stock looking truck look foolish :
https://www.amazon.com/s?k=signal+s...ignal+stat,aps,181&ref=nb_sb_ss_ts-doa-p_6_11
I don't know the junkyard / swap meet / auto jumble situation in No. Platte but there should be plenty of these used for dirt cheap, I've never yet had an older American made one not come easily back to life with only cleaning necessary .
Some here may have purchased new ones like the world famous Signal-Stat 900 or similar that they can recommend .
I have zero knowledge on the Pacific Industries kit(s), add a hyperlink and I'll give it a look .
If you only have one taillight as original you're going to have to run at least one new wire from under the dash back to the passenger side lamp you'll need to add for the turn signal .
LED's too are a good idea, thinking about your request made me realize I should have been making notes and taking pictures as I really believe in LED bulb upgrades, they're FAR safer and easier on the generator or alternator and God knows I have bagfuls of LED bulbs I've tried and not liked for various reasons .
Vinegar, specifically White Vinegar strips off rust like <magic> but, it also allows flash rusting to I prefer to use diluted Phosphoric Acid, lets see if I can add some pictures of a fuse box service I did Tuesday of this week now the taillights are *much* brighter, the turn signals and and even the horn I had been thinking about replacing, toots *perfectly* at idle on a 6 volt generator equipped vehicle .
Hm ; it appears I need to to something differently, please wait .