I have been searching all over for some guidance on this, and I have not found much to speak of so I thought I would post the question here.

I just purchased a 79 F150. It is all original except the engine (351C) and I would like to keep it that way. The biggest issue I have right now is with the sound system. The driver's side speaker does not emit any sound 90% of the time. Occasionally it will pop on for a few seconds but most of the time I get nothing.

The first thing I did was swap the speakers to see if a bad speaker was the problem. Both speakers worked when hooked up to the passenger side wires and neither worked on the driver's side.

I noticed the wires looked pretty rough, so I ordered new OEM wiring harnesses and installed them yesterday. I am still in the same place. The passenger side works but nothing from the driver's side.

The only wires I did not replace are the ones coming out of the radio itself. I am hesitant to open the radio up because I do not know if there is anything I can even work on inside it to fix it.

Does anyone have any ideas?

Thanks in advance!

 

Not to be an azz but...... have you tried adjusting the fader or balance feature on the head unit?

We all will know the answer if ya don't reply and this thread dies off.

 

Do you just run the speaker wire through the door jam? Is it possible the wire is rubbing against the metal and peeling the wire shield?

 

I'm just spitballing here, but it kind of sounds to me like you may need a new had unit. Do you have a voltmeter? If you do, turn on the radio and measure the volts coming through the wires. Do you have constant voltage or do you have "blippy" voltage? You can try spraying your radio dials with electrical contact cleaner...over the years, dust and dirt and crap can get in there and turn the contacts in those dials greenish. Hit them with contact cleaner and turn the dial back and forth a bit...that may work for you

 

Yeah the first thing I did when I noticed the sound only coming from one speaker was move the fader. That didn't do it unfortunately.

The speaker wire is run properly. I purchased OEM wiring harnesses, so the wires going through the door pass through rubber grommets. The original wiring was pretty rough and I suspected that might be the issue, but it persist even with the new wires.

I do have a multimeter. I will check the voltage on the wires. What should I look for as far as voltage? 12V? Should it be steady at 12V or should I expect it to fluctuate?

Thanks for the help!

 

Did you adjust the balance?

 

Voltage should fluctuate.

If you're getting sounds randomly It sounds like there could be a loose connection causing an intermittent open in the circuit.

Move the wires around while it's on, see if you can get a signal through.

 

Also...make sure your power wire is not wrapped around your speaker cables. Sometimes you can get feedback noise. I've experienced it with rca cables hooked to avoid before.

Or you can hook the speaker to the radio without having it in the door.

 

Still kinda sounds to me like its an issue in the headunit itself. See what that volt test does for you. If you get nothing, then you know the issue is in the headunit and/or its wiring.

 

If its not wires and the speakers are new, It's the head unit. I'd try some contact cleaner in the controls before replacing it if its a stock unit. You'd have to take it apart but that's a cheap fix.

 

Hellooooooo????

There's the front and rear fader... but what about balance??

 

When i said fader I meant balance sorry. The truck only has door speakers, so no front and rear. I will check the voltage on the side that is bad and see what I get. Other than contact cleaner, is there anything that can be done to the original radio to make repairs or will I need to purchase another one assuming the contact cleaner doesn't work?

 

I finally got around to testing the driver side wires and they read a steady 12.5V when the radio is on and the other speaker is working. All I can guess at this point is that something is wrong with the radio itself. The wiring is brand new and both speakers are verified working. The balance is set in the middle and it doesn't matter which way I move it. Has anyone ever taken a stock 79 radio apart to make repairs by any chance?

 

are you saying you have a steady 12.5 volts on across the LH speaker wires?

 

Yes. It fluctuates but only slightly, and it does not change when I adjust the volume ****. The side that works runs between 7 and 8V or so and goes up and down when you adjust the volume ****. Any thoughts?