problems with car stereo in a motorhome

[scubadog40]

Ok think I have a good one here for you guys. See if I can find some help.
I have a motorhome on a ford frame. Class A
Ok when I hook up the front L.R speakers they work fine. If I go to just front fine there too. And the L,R works right on stereo.
Now I have two wires left from the motorhome and I have my 4 wires left from the stereo. Left +- Right+- . Ok if I touch any of the 4 wires I have left from stereo to ether one of the two wires I have left from the motorhome one of the speakers in the rear will work. That doesn't make since because the - wire should not make them work. The other problem is say I put the + wire from L to L rear and the + wire from right rear to them2 wires I have from motorhome it works but when you try to turn off the rear speakers they still work. Works the same if I do it with the - wires from the stereo. It's got me. Anyone think they might know why? Please let me know if you do. Thanks William

[PaulD]

how old is this motorhome and who did the speaker wiring ? Becareful, the speakers may be wired for a common ground, meaning the - side of the speaker is connected to the frame. Unles it's an older stereo designed for that, you will damage the outputs in short order.

[scubadog40]

Originally Posted by PaulD

how old is this motorhome and who did the speaker wiring ? Becareful, the speakers may be wired for a common ground, meaning the - side of the speaker is connected to the frame. Unles it's an older stereo designed for that, you will damage the outputs in short order.

It is a 2001. I wouldn't think it is a common ground.

[PaulD]

are you sure thos speakers are not being powered by a seperate amp ?

[scubadog40]

Originally Posted by PaulD

are you sure thos speakers are not being powered by a seperate amp ?

yes sir. Thanks for still trying to come up with something. Leaving Thur. for Fla for 5 weeks. Can't wait. Got my bike ready to tow.

[PaulD]

well, you can't power a speaker with just one wire. I have also seen older stereos that used the same ground wire for both left speakers and another single wire for both right speakers.