Wiring scematic of xm-754hx - Sony XM-754HX Car Audio Amplifier

There is a lot of info here
http://www.1728.org/guitar.htm

are you talking about how to turn your amp on and off? if you are then that is your remote wire. it comes from the cd player to the amp. there is no switches on amps to cut it on and off

i had the same amp same problem they just wear out

Hiya try
http://www.icpowerx.com for the Mosfets, you will probably need to replace driver transistors also (not always but sometimes they go). Also check the resistors to output, they will be the big white ones.
Go here to read on testing FETs
http://www.4qdtec.com/mostest.html
Just to be sure. If one is blown, replace all

What make/model amp is it?

When the amplifier shows an offset fault, it's generally because there is DC voltage present on the speaker terminals. The amp has shut down to protect the speakers.

You can do it either way it doesnt matter.

Not all controls are the same. Manufacturers use various schemes to control the level of the audio. If you use a control that's wired improperly, you risk damaging your amp.

Green is good. Amber or red is bad.

Here is the link to the user manual http://esupport.sony.com/US/perl/model-documents.pl?mdl=XM754HX&LOC=3 All the connections and installation wiring are well documented in english and french. Hope this helps - please ask again if you have any problem :)