Well people I have been searching for well over a couple months to find the answers to this. My 1978 f150 had a old cassette tape deck in it and whoever's hands this thing passed through, they really did a number on the wires in back. I'm trying to finalize the retro sound Bluetooth radio I have but these two wires are bugging me 😡. The red/black stripe and ... what could be grey/orange stripe??? What are these two? PO had more wires connected to nothing than I've ever seen and I've already ran a ground wire but can't play the radio without power😅 so can anybody let me know what goes where and I will be eternally grateful.
Thanks
Whichdoc

 

Here is my radio wiring collection from FTE.

"The OEM radio was powered by a GREEN 2-terminal pigtail. YELLOW with a BLACK stripe is switched power, BLUE with RED stripe is dash illumination. Do not mistake the BLUE with RED stripe wire for ground. The OEM radio grounded through its mounting chassis. The speakers were connected over a separate pigtail.

Look behind the glove box and find a connection the goes off the green and yellow. GREEN with YELLOW stripe wiring is hot-at-all-times power for the courtesy lamp circuit. You can use that. There is a 3-connector pigtail behind the glove box (which also goes on to power the cigarette lighter).

It's not the stock radio wire because the stock radio didn't need hot-at-all-times power (EXCEPT the factory digital AM radio for clock memory).
solid black—power
blue with red stripe--dial light
black with gray dashes—ground
orange with green dashes--right speaker
white with green dashes--left speaker
Assuming an AM/FM stereo and stock wiring harness.
Purple is ground, right speaker is white and left speaker is orange."

 

Based on a) your saying the PO got inventive with the wiring and b) that red wire, I'm betting if you trace that red wire back to where it starts you will find it is an aftermarket addition to the truck. Best to check those two wires by function - the gray with red could easily be the blue/red light wire, and should turn hot when you turn your lights on. The red wire I suspect you will find is a 12V power lead (hopefully fused!) and would test hot more or less all the time, either switched or constant. If either of them has an unknown function, meaning not 12V for lights or 12V for the radio main power, best to just trim them off and find that connector by the glovebox (it is pretty conspicuous!) In a perfect world, you would run one fused main power line to the switched on of that connector, the backup power which requires constant juice to the constantly on unswitched line of the connector, a new ground to a nicely shined up clean ground, if you have a dimmable light in the BT unit connect it to the blue/red light wire. Me, I like to run new fresh speaker wire no matter what - I tend to find too many bad connections, ugly splices, breaks etc. in factory wiring. YMMV.

 

Thank you both for the input 😊. Houston Dave the radio did have that connector on it but different color wires. The gray/red stripe seems to be coming from the ignition switch so I'll tape them both up and take your advice. Wish my spine was more catlike to get around these uncomfortable truck nooks and crannies.
Thanks Again
Whichdoc

 

If it tests as switched power (meaning the ignition turns it on) you are in good shape. Most current decks require both a switched main power lead and a constant-on power lead to run the memory in the unit which saves your preferences, station presets, etc. but rarely it will ask for a third wire to tap into the dash lights so when you dim your dash lights the radio lights dim too... wish I had that on mine, it's a nice feature and the constant all-on radio lights are too bright when driving down a dark road.

 

Thanks Houston. I'll post some pictures of the outcome. My fingers are permanently crossed with everything I have been fixing on this truck since I bought it 5 years ago. I hate doing the electrical work.