I am no electrician ...but i am trying to sort out the wires on this Cali import its a bit of a mess under the glove compartment which has now disintegrated ...and making it easier to view everything . However there is two wires which are green which are joined together coming from a block which have a sleeve saying ....Rear LCH and another coming from the same block but Purple 2 off with a sleeve saying Rear RCH . Are these some thing to do with a radio speaker wires ?
Most likely speaker wires - Green and purple are for rear channels, white and grey for fronts - 2 of each, one with a black trace
Get a 1.5 volt battery, tap the two cores of each 2 way cable on it and see if you can hear crackling noises from a speaker in the back of the bus..
I will try that Mike ...speakers ( Battered ) are in the doors . Just taken the lenses of the rear lights , soon as you touch the lamp body it is as brittle as paper . Probably the hot weather of Carlsbad California where it seems to had all the servicing done up to 98 thou miles in the service book . Next job to buy a new 12 v battery and see what works .