Radio not working

[Ranchhand1990]

Did some wiring work on my bosses 91 gmc. Before doing so the radio worked fine. Now everything is working except the radio. I am not getting any sound, static, or lights on the interface. I used a meter to check voltage at the pigtail right where it plugs into the unit and it has a full 12 volts. I can’t seem to get 12 volts on the interface side on any of the wires. I have tested two different radios and neither one is giving me 12 volts on the outlet from the radio to the interface. Any ideas what to check?

 

[kennythewelder]

There are 2 power sources for the radio. 1 stays hot all of the time. This keeps the memory. Station presets, ECT. The other wire, comes in with the key. This turns the unit on, when you turn on the key. If that wire, doesn't have power, the radio will no come on. Not 100 percent sure, but it's usually a yellow wire. You may have blown the fuze. Double check all of them.

 

[Ranchhand1990]

There are 2 power sources for the radio. 1 stays hot all of the time. This keeps the memory. Station presets, ECT. The other wire, comes in with the key. This turns the unit on, when you turn on the key. If that wire, doesn't have power, the radio will no come on. Not 100 percent sure, but it's usually a yellow wire. You may have blown the fuze. Double check all of them.

So I just checked the constant power I have 10.3 volts and double checked the intermittent wire and it has 11.36 volts. When I check the voltage coming out of the radio to interface the voltage was about 3 volts for both wires.

 

[kennythewelder]

Personally, I haven't fooled with the OE stereo, other than to remove it, and replace it with a Bluetooth unit. Not real sure, what you should have between the head unit, and amp.

 

[Erin]

You did wiring work where on the truck?

 

[Ranchhand1990]

You did wiring work where on the truck?

Where the harness ties together on the firewall. I burned up the connection trying to clean it and had to rewire new pigtails on both sides of the firewall. Electrical cleaner, a wire brush and a battery I did not disconnect. I think you get the picture.

 

[pressureangle]

So I just checked the constant power I have 10.3 volts and double checked the intermittent wire and it has 11.36 volts. When I check the voltage coming out of the radio to interface the voltage was about 3 volts for both wires.

If battery voltage is good, 12.5+, you have some *very* bad connections. Check the radio fuse first; I've seen blown fuses carry voltage through the carbon tracking but will not carry current.