Ok so I have a 84 F-150 and I was putting in a new radio today. Well I went and got the mounting kit and the wireing harness. I wire it all up plug it in and nothing! it wont turn on. I know the wires suppling power but its not getting to the radio. I tryed the radio in my house off a power supply and it worked fine but not in the truck. Im lost! What could be the problem? I have a clean ground, all wires hooked up correctly, no amps just a head unit. I really need to get this figuard out by the moring.



Thanks,
Alpine

O ya anyone know how to remove the door skins to get to the speakers? I think I got it but want to make sure!

 

Did you have problems with your previous radio not working before? If not, the problem is one of these.

1-The wiring harness is not plugged in tightly enough.
2-The wiring harness is not the correct model for your vehicle.
3-The stock wiring in your vehicle is faulty, causing no power to pass throught the harness to your new head unit.

If you have a multi meter, you can troubleshoot this problem pretty quickly and painlessly. Switch the meter to DC voltage and test the power leads in the harness from the vehicle, then plug in the new audio harness and test the power leads in that one as well. If your not getting voltage through the new harness, it is obviously bad.

 

Smokey hit the nail on the head. Also Double check you gorund as well, make sure it reads as a good ground when doing your multi-meter testing.

LH

 

Good point Licoln. I wasn't even thinking about the ground to the head unit. Definately make sure there is a solid ground to the head unit.

 

Some aftermarket head units use the antenna lead as a second ground and won't turn on without it. Make sure your antenna is plugged in when trying to power it on. A often made install troubleshooting mistake.

 

Well, there's a few things that I would want to troubleshoot, before assuming something was faulty...

Much less of a chance that something is actually faulty, generally.

First, do doublecheck your wiring to the harness...
Make sure your black wire is going to the ground on the wiring harness...
Red wire is going to a switched-power wire on the wiring harness...
Yellow wire is going to a constant-power wire on the wiring harness.

Now, if the head unit isn't powering up, grab a DMM that measures impedance (continuity, is really what we want to measure here).
Put one probe on your door striker loop (that's generally always a good 'ground' reference), and put the other probe on the head unit's wiring harness pin that corresponds to that black wire (with the wiring harness plugged into the truck's socket).
You SHOULD show continuity.. or almost 0 ohms of impedance... that would indicate a good ground.
If you show no continuity (something close to infinite resistance... or very high, anyways), that's an indication of a bad ground.
Easy to fix.. run your own wire to ground.. find a wire under your dash that terminates in a ring terminal that's bolted right to the firewall, there are usually several. Use that point for your ground.

Next test is voltage... using the voltage setting on the DMM.
Again, with the wiring harness adapter plugged into the car's harness socket, but the head unit harness unplugged from the head unit, measure the pin that corresponds to the yellow wire.
You should measure voltage with the truck turned off.
If you don't, that's a problem. Check for inline fuses on the wire... check your connections. Check the fuse box for blown fuse.

Now, moving on to the red wire.
This one shouldn't measure any voltage with the truck off, but when you turn the truck on (or at least to "ACC"), you will get 12v (or more).
If you don't, that's a problem. Check for inline fuses on the wire... check your connections. Check the fuse box for blown fuse.

Check the HU for built-in fuses poking out the back also.

You'd be surprised how many times this turns out to be just a blown fuse... somewhere....
During the install, you might have accidentally let the yellow wire hit something metal.. just stupid stuff, and POP.. blown fuse.

Good luck!

 

One more thought that I had..
Your truck is pretty old...
I don't know how your stock head unit mounted in there, but it could easily be that the old head unit was grounded via it's chassis, being bolted to the metal bracketry in your dash, which in turn was bolted to the car's chassis.

A pretty ugly thing to design in that way, but it might mean that your truck's stock harness doesn't actually have a ground wire. Check to see...
Test #1 that I listed above would fail, if this is the case.. so you would be covered in that case...

If that is the case, no problem.. just run your own ground wire, like I posted above.

Good luck!