Ok, this is a little weird, but apparently the PO of my 1986 K5 Military blazer was a wiring genius. (sarcasm) There's a pioneer cd player installed and it works, but only when the headlights are on. So my question is, why would somebody wire a stereo like this, and how do I remedy this situation?

Some of the wires on the stereo still have their designation tags on them, and there is a wire labelled pos to battery that goes into the fusebox at a location that gets 12v whenever the ignition is on, but there is clearly another power wire that I can't figure out that runs to the headlight switch (why??)

 

test the wire that is hooked up to the POS coming off the Pioneer for 12v with ignition on. It sounds to me like the POS is hooked up to the dimmer wire instead of the switched power. Does the unit retain the clock and station settings when turned off and on?

 

red.. is constant power.. goes to a battery sorch power at all times...
the yellow should be on a acc. power.. should only have power when key is on... and yes sounds like its hooked in into the dimmer wire orange i belive...

 

No it does not.

So let me get this straight: The pos to battery wire should go to a constant 12v source, regardless of wether or not the key is on?

 

Yes, that power retains the memory in the stereo and keeps the time set in the clock.

 

I believe you have that backwards, Yellow being power, red being switched. I haven't wired a headunit in quite some time but I do believe that's how it is.

as for the original poster, It sounds like you wired the red (switched power) to the dimmer wire (orange, or orange with a white stripe) instead of to the switched power wire.

 

i didnt even notice i wroth that all backwards.. yes yellow is battery hott at all times and red is a 12volt switched.. acc. wire

 

Red is switched power, but should NOT be wired to the dimmer, it should be wired to the radio fuse. If that wire is hooked to the dimmer then that would cause the radio to only work when the lights are on as well.

If you don't connect it to the radio fuse, either via the wire that should be SOMEWHERE behind the dash in the vicinity of the head unit, or by tapping into the fuse in the fuse box itself, then make sure that wherever you do connect it loses power when the truck is shut off. Otherwise you will have to remember to turn the radio off every time you exit the truck or you will, over time, kill your battery.