Looking for a good place to tap for UNSWITCHED power

[cvvick]

Thanks for the help on switched power

 

I realize I also need a UNSWITCHED power source for the stereo. Is there a good place to tap under the dash?

[Mike Self]

Presuming this isn't a megawatt stereo/amp, the most convenient spot is the fat red wire on the back side of the ignition switch.  It comes VFR from the battery (no fuses, so be sure and have an in-line fuse for your stereo). 

 

Check with a voltmeter (ign off) to make sure you have the correct wire, then use a piggyback terminal to hook things up.  Both my cars are wired that way and it works fine.  

 

Just remember...if you have a radio with a memory, that's the wire that should be connected to the "always hot" lead on your stereo.  But use a switched (off with the ign off) source for the rest of the stereo, or you'll have to remember to turn it off every time you leave the car.  When our cars were built, radios didn't have memories, so you connected your radio to a switched power source.

 

mike

 

mike

 

[John76]

The problem with tapping into a red wire is that it is not protected by a fuse. This would be OK if your stereo had its own fuse on the power cable.

Did I send you the attached diagram of fuses #1 and #2?

A good fuse-protected 12V (unswitched) source is the red/yellow to the lighter, or the red/white to the hazard button.

I'm not a fan of tapping into the ignition switch harness.

John

 

[Tdh]

Another option would be to wire up an alternate fuse box under the hood connected directly to the battery, and independently wiring circuits from the box to suit your needs. Something like this:

ST Blade Fuse Block - 6 Circuits with Negative Bus and Cover - Blue Sea Systems

WWW.BLUESEA.COM

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Compact ATO® / ATC® fuse block consolidates branch circuits and eliminates the tangle of in-line fuses...

 

[cvvick]

23 hours ago, Mike Self said:

Presuming this isn't a megawatt stereo/amp, the most convenient spot is the fat red wire on the back side of the ignition switch.  It comes VFR from the battery (no fuses, so be sure and have an in-line fuse for your stereo). 

 

Check with a voltmeter (ign off) to make sure you have the correct wire, then use a piggyback terminal to hook things up.  Both my cars are wired that way and it works fine.  

 

Just remember...if you have a radio with a memory, that's the wire that should be connected to the "always hot" lead on your stereo.  But use a switched (off with the ign off) source for the rest of the stereo, or you'll have to remember to turn it off every time you leave the car.  When our cars were built, radios didn't have memories, so you connected your radio to a switched power source.

 

mike

 

mike

 

Thanks, yes, the stereo has an in-line fuse so this should work fine. I think I tap into the red/white wire on the hazard switch to avoid having to disassemble more and keep all the connection in the same place.

[Lucky 7]

It requires a bit more disassembly to get to, but coming off the lighter would allow you to avoid a splice. It’s an easy spot to drop a short Y leash that’s easily removed later. May or may not matter to you, but worth mentioning.