> I just bought an older Kenwood powered subwoofer for my '85 
> Wolfsburg Westfalia, and it does not have the signal-sensing 
> power switch like the newer ones do.  I'm wondering how to 
> power it without draining the battery.
> 
> I have a new Pioneer head unit; if it has a powered antenna 
> wire (I'm not sure if it does,) can I use that?

If the Pioneer unit is relatively new, the power antenna lead should provide
current whenever the unit is powered up. (Some older head units only
provided power to that lead when the radio was actually playing.)  However,
the sub may draw more current than this lead is intended to deliver. Your
best bet is to give the sub a good direct power source (fused, of course)
but put a relay inline. Use the power antenna lead to trigger the relay.
This way, when you turn on your Pioneer, it will trigger the relay and turn
on your powered sub. Basically you are creating your own "signal sensing
power switch."

- Ron Salmon
  The Bus Depot, Inc.
  www.busdepot.com
  (215)  234-VWVW

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