Ok Im in the process of installing a new aftermarket cd player and I am looking for a wire harness to plug into the factory wire harness in the dash to wire up to the radio wire harness. The factory harness that I have is one with 3 wires and then one with 2 wires. I looked around and cant seem to find one. I can get it wired up without one but I dont want to have to cut off the factory plugs.
Any help would be appreciated.
Thanks,

 

There are no aftermarket harnesses for your truck. The wiring must be done by hand. If you don't want to cut the original wiring, you can cut off matching connectors from an old factory radio and splice that into the aftermarket pigtail and make your own adapter.

There is only one connector that went to the original radio. It's green and female. YELLOW with a BLACK stripe is switched accessory power; BLUE with a RED stripe is illumination. I mated to this using male spade terminals; this allowed me to not cut the wiring.

The original radio grounded through its mounting bracket. The other connection you'll need is hot-at-all-times power; there is a pigtail behind the glove box (GREEN with YELLOW is the courtesy lamp circuit).

The other pigtail you're looking at is probably for the front speakers; for that you'll need to use my first idea (cut off the matching pigtail from another radio).

 

Thanks for the reply. I like the idea of making my own harness from radio wiring. Will have to check out the junk yard and cut one from an old radio. My radio had 2 plugs on the back. The green 2 wire female you mentioned and also a black 3 wire female. Im assuming those are where the speaker wires are?
Thanks for your help

 

I have not seen anyone that makes one up. I normally just run new to the fuse block and for the speakers. No sense putting in a new stereo and using 30yr old wires. I have in the past picked up an old stock radio from the junkyard and taken the pins out of it and made my own adapter. I have not seen the plug on the '78 but there is a good chance the pins are standard round or spade type that you can pickup at radio shack and solder onto the harness that came with your new stereo. Just make sure you insulate them as they would be very close once plugged into the stock connector.

 

Oh yeah I guess I forgot to read your last sentence lol

 

LOL FMC you must type faster than I do.

 

Oldbone - yeah your right one harness has round and the other looks like the spade type. I can use terminals and plug into there. I think I'll keep that in mind if I can find any harnesses at the junk yard.

 

Ok I finally got the cd player custom mounted and all the wires hooked up but have an issue. The radio plays for awhile then shows Protect on the display. By the way I have a JVC KD-R310. I googled it and it says that either the constant power wire or the switched power wire is coming in contact with ground. I doublechecked my wiring and those wires are soldered connections with heat shrink and are in no way touching ground. I later found out that the radio was displaying Protect when the radio mount touched the dash. So I figured I had to insulate the radio from the metal mounting bracket. So I insulated the screws and put plastic pieces between the side of the radio and the bracket. I checked with a meter for continuity and the radio is not contacting the mounting bracket at all. Has anyone else had this issue putting a cd player in these trucks?
Any help would be appreciated
Thanks

 

Bttt still having this issue

 

The message you're seeing on your head unit's screen is specific to that head unit and has nothing to do with the fact that it's in a 73-79 Ford truck. Unless someone here happens to have that exact model head unit (doubtful), your best bet would be to try and get ahold of JVC tech support or find a manual online.

 

The headunit case being grounded to the mounting plate in the dash has nothing to do with your problem. Check your wires to the speakers and make sure none of those are grounding out. Otherwise sounds like you have an internal short. In other words your head unit is toast.

For head units I reccommend Pioneer or Alpine.

 

Ok I'll check out the speaker wires and see if anything is going on there. Then I'll see about taking it out of the truck and powering it up to see if it does it then. If so I guess I'll trash it and get something else.

Fmc400 I knew it didn't have anything to do with the 73-79 trucks I just didn't know if a modern radio had to be insulated cause of the metal dash in these trucks. I've never done a radio install in a vehicle this old.

 

Protect mode means theirs a short somewhere. Either in the input wires(you already checked) or its something internal thats burnt up.

 

Gotcha. The answer is no, the fact that you are bolting the head unit chassis to grounded metal on the truck is not a problem.

Also, if power going to the head unit were shorted, there wouldn't be enough voltage to the head unit to power the display. You'd also either pop a fuse or fuse out the wiring.