Radio draining battery

[fishinsam]

So i have been having battery drain issues and from reading up on here have discovered the method of disconnecting one battery terminal and putting a test light between the battery terminal and the lead that should be on the terminal. If the light is on when the truck is turned off, you have battery drain issues. i started pulling fuses and the light got a lot dimmer when i pulled the 20 amp fuse the ranger manuel calls the "jbl" fuse. i assume this is for the audio system. When i bought the truck it already had an aftermarket head unit installed, and obviously not correctly. When the fuse is pulled the head unit will still turn on, however none of the speakers have power. i further inspected the problem by putting a volt meter between the blue remote wire and the ground wire at the back of the radio (when the truck and radio was off). it was reading 4.7 volts. I believe it should be reading 0 volts and that the remote wire is part of my problem. Although i dont understand the wiring well so i would appreciate some direction as to testing the wiring further to find out and fix my problem. Another issue with the radio i am having that may be related is a engine wine coming out of my speakers (as the rpms increase, the frequency gets higher). The speaker wine only happens part of the time and i believe is caused by a difference in grounding potential. Thanks for any input anybody may have.

 

[4.0B2]

Yeah you probably should just rewire the radio.

And what do you mean by the speakers don't have power? As in they don't work or as in you checked for voltage? Just asking...

Is the factory harness still in the dash? Or is it a complete hack job?

 

[kryptonitecb]

Radios have a small draw when the vehicle is off in order to keep the presets. 4 volts seems a bit high though.

Sent from the road while ignoring traffic

 

[Chris_North]

Just to clarify, when you say blue remote wire you mean the wire telling the head to come on or the wire from the head to another accessory (such as an amp) to tell the accessory to come on? Is your voltmeter digital or analog?

I'm not a big audiophile or anything, but in my limited experience I've found that some whining or buzzing is normal, especially if an additional amplifier is used.

 

[RonD]

Have a look here for wiring colors for Ford Radios
http://www.therangerstation.com/tech_library/EDiagrams/index.htm

look at power accessories radio 1 of 2

If the radio whine comes on on AM radio then it could be the antenna is loose, there is also a capacitor connected to the coil power that is there to prevent that whining.
In above link look at Ignition and pick your model.
Don't let the years on the diagrams through you, Ford doesn't change things much.

Like kryptonitecb said a radio will always draw some power for saving presets and if it has a clock built-in.
But it would be minimal.
I would continue testing circuits, leaving the radio fuse out, you said light got dimmer, but didn't go out, so find that other power draw as well, probably dome light since door was open, lol, or PCM(computer)

 

[Lil-Pony]

ok to start off is this a factory radio or an aftermarket radio/ do you have any additional amps for subs or a 4 channel for your mains. 5 volts is what ford has used for all 'their' remote turn on for devices like rear entertainment systems amplifiers etc.

 

[fishinsam]

lil pony - "yes it is an aftermarket radio, and yes i do have a two channel amp that is bridged to power one small sub"

RonD - "The radio wine is even when using my aux cable to my smartphone, and i'm not sure if it's related to the large battery drain or not"

Chirs_North - "The wire that comes from the truck to the head unit, is also spliced into a remote wire that travels back to an amp, and the voltmeter i used is digital"

4.0B2 - "When the fuse is pulled, the head unit turns on, but no sounds comes out of the speakers, i did not check them for volts, and the factory harness is still in the dash"

If i can't fix the problem i might just have to break down and have a shop fix it. Thanks for all the input guys

 

[4.0B2]

if the factory plugin is still in the dash... i'd get a wiring adapter, wire up the headunit to it, and plug it in the factory harness... then go from there.

 

[Lil-Pony]

The blue wire off the back of the aftermarket radio should have 12v when the radio is on to turn your amp on. And there should be no voltage present when the radio is off.