weird electrical issues...

[mrbrink]

I decided to swap out the non working factory ford radio for a cd player in my 85 3/4 ton the other day, and now I've got electrical problems. Since I installed it, my dash lights haven't worked. It blew the fuse, and as soon as I put a new one in and hit the switch the fuse blows. I didn't change any wires, I simply spliced in the new harness using a 12 volt test light to figure out constant and ignition and thats it, I didn't touch any wires that weren't part of the factory radio. Does anyone have thoughts on this or where to start looking for the short?
Also, the radio worked fine for a couple days, and now its like it isn't getting enough power. low volume it works fine, but as soon as I turn it up it'll turn off and on until I turn the volume down. Same deal if I put a CD in it, and I swapped the head unit for another one I had and the same thing happened. I'm thinking not enough power going to it but I'm at a loss with this whole thing.
Thank you in advance,

 

[burtcheca]

You need a multimeter and a 12 feet of #16 wire to do this tests.

Disconnect the radio and put a new fuse in place. If it doesn't blows it again when you turn on your dash lights then you know is something in the radio wiring. Check if the dash lights work when the radio is disconnected, if you didn't mess up anything else they should work. If the radio is OK I would check carefully every wire connection, maybe two wires are switched wrong.

Connect the speaker's wires and ground only, then bring a wire from the battery's positive and connect it to the radio B+ wire (usually red). Everything should work fine, even your dash lights.

There is a wire that will bring only some current to your radio to keep some information saved (pre-selected stations, hour, etc.) This wire does not provides enough current to run the radio, CD player and amplifiers, specially when you crank it up. You can identify this wire because is thin and always reading 12v, even when the ignition switch is off. The B+ wire turns on only when the switch is on. I don't know what kind of new radio you are installing but if the amplifiers deliver more than 12 watts per channel you should have at least a #14 cable supplying to your B+.

I hope this will help you. Pray before doing any work, you'll be surprised to know how many things are going on around you that you don't know or see.

Burt.

 

[redneckaggie]

Does that truck actually have a constant b+ wire cause i ran a radio on a 6.9 (dont remember the model but mid-late 80's and had to run my own b+ because the factory radio did not have one as it did not have electronic presets.

 

[mrbrink]

I figured out all of the radio issues, now I'm just down to the dash lights. Positive battery cable was really corroded and wasn't getting a good connection and I'll try the test for the lights tomorrow, thanks!