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switched power source

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=118504
Printed Date: March 29, 2024 at 2:34 AM


Topic: switched power source

Posted By: captfrank
Subject: switched power source
Date Posted: December 13, 2009 at 8:26 PM

Hello all, I have a 2005 Chevy Express van and would like to power my add-on portable xm radio unit with a switched source. I'm having trouble locating an appropriate and convenient spot. All of the sources I've located under the dash are unswitched. My accessory plug-ins both have unswitched power.



Replies:

Posted By: i am an idiot
Date Posted: December 13, 2009 at 8:48 PM
Whatever you do, when you find a switched source, do not cut the cigarette lighter plug from the end of your unit.  Most of them run on 5 or 6 volts, the cigarette lighter plug includes a voltage regulator that is needed to powr the unit.




Posted By: tommy...
Date Posted: December 14, 2009 at 8:13 AM

i am an idiot wrote:

Whatever you do, when you find a switched source, do not cut the cigarette lighter plug from the end of your unit.  Most of them run on 5 or 6 volts, the cigarette lighter plug includes a voltage regulator that is needed to powr the unit.

DITTO...Just wrap wires around the cig plug...Sometimes only one of the prongs on the side need ground...the other side is just a clip...Then use those wires you wrapped to attach to an accessory circuit and ground...!



-------------
M.E.C.P & First-Class
Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!




Posted By: tommy...
Date Posted: December 14, 2009 at 8:29 AM
How are you checking these wires...? Are there any accessories you notice that turn on with the key...Like the cig plug...Does that only work when the key is on...Or is it constant...?That vehicle has more then one cig plug...?

-------------
M.E.C.P & First-Class
Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!




Posted By: boogeyman
Date Posted: December 14, 2009 at 10:47 AM

Go to Auto Zone or similiar and get a $7.00 female cigarette lighter receptacle with the 2 wires coming off of it . Attach the red wire to switched wire in car , attached the black wire to ground , Plug in male receptacle , no cutting or wrapping and taping.....good quality job.





Posted By: captfrank
Date Posted: December 14, 2009 at 11:34 AM
I'm checking the wires in different key positions and even with the vehicle running. So far all have given me 12 volt power with the key off as well as on. The only switched source I've found so far is to the driver's seat sensor for the seat belt alarm. The voltage is a little lower there in accessory position, 10.5 v. With engine running it is 12.4 v. It would be nice to find a convenient source under the dash. I'm still working on it.




Posted By: tommy...
Date Posted: December 14, 2009 at 3:38 PM
boogeyman wrote:

Go to Auto Zone or similiar and get a $7.00 female cigarette lighter receptacle with the 2 wires coming off of it . Attach the red wire to switched wire in car , attached the black wire to ground , Plug in male receptacle , no cutting or wrapping and taping.....good quality job.


I see...But now your out $7.00 bucks...The wires would be under the dash and not exposed...So whether you buy the receptacle or wrap and tape...You cant see it...! I guess im taking exception to the "quality" part of your post...I strive for quality...! And buying a receptacle is just not necessary...It is basically the same dang thing...! I think he needs the switched wire info...Got that...? You still have to attach the wires and secure the plug...But to each his own...! Think ive done just about 1,000 of these "hardwires for sirius,xm and radar detectors...



-------------
M.E.C.P & First-Class
Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!




Posted By: 91stt
Date Posted: December 14, 2009 at 3:59 PM
Have you tried the power window wire from the window RAP relay to the switches? It is dark green and you should be able to find it in either kick panel. Since it is operating through the RAP relay, it will remain powered until you open the door just like the radio.




Posted By: captfrank
Date Posted: December 14, 2009 at 6:07 PM
That would be great, but vehicle has no power windows (basic cargo van). I tried all the leads in the basic factory head unit, but could find no switched power at all. That surprised me. The red with white stripe had over 12 volts and another had less than one volt, both unswitched. Maybe I can tap into the ventilation fan wires?




Posted By: boogeyman
Date Posted: December 14, 2009 at 6:29 PM

have you tried the ignition harness?





Posted By: i am an idiot
Date Posted: December 14, 2009 at 8:33 PM
There is not a suitable wire at the ignition harness.  There is a wire that goes hot with the key, but it is not capable of enough current to even trigger a relay. 




Posted By: 91stt
Date Posted: December 15, 2009 at 10:14 AM
captfrank wrote:

That would be great, but vehicle has no power windows (basic cargo van). I tried all the leads in the basic factory head unit, but could find no switched power at all. That surprised me. The red with white stripe had over 12 volts and another had less than one volt, both unswitched. Maybe I can tap into the ventilation fan wires?


There is no switched power to the radio; it uses the class 2 data bus to determine when the ignition key is on.
The pink wire in the ignition harness should be able to work for you. It supplies +12V to the fuse box under the hood; to 10 fuses if you don't count the 2 that are not used.




Posted By: captfrank
Date Posted: December 16, 2009 at 12:36 AM
Thanks, I'll check out the ignition harness.




Posted By: captfrank
Date Posted: December 31, 2009 at 9:11 AM
Thanks a lot. The pink wire is doing the trick. I came directly off of it and fused my lead to the xm radio unit. I hope that I haven't created any unforeseen problems with the ignition!
captfrank




Posted By: boogeyman
Date Posted: December 31, 2009 at 2:59 PM
congratulations......There is almost always a switched wire at the ignition.




Posted By: tommy...
Date Posted: January 02, 2010 at 8:58 AM

Not to long ago...One of my techs installed something to the ignition harness for switched power...The unit then lost its ground...And i got a few calls from the auto repair shop...Something about ignition was staying powered up...and every terminal on the unit was showing a constant 12 volts...! Ended up being the customer had "thought" he had dis-connected the unit...But just took the ground off...! Just make good connections...And if you are ever done with the unit...Completely de-install it...!



-------------
M.E.C.P & First-Class
Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!





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