Stereo Wiring Diagram? [Archive] - Toyota MR2 Message Board Aug 20, 2012i need help i cant find a wiring diagram to connect my new stereo (a cheap stereo 4 my ipod) im going to need to wire the stereo straight to the stock wires that have been cut 1991 MR2 base.Toyota OEM Stereo Wiring Information [Archive]Jun 17, 2016Where are the Neg. Speaker wires on the 14 pin. radioAug 23, 2012See more results MKII Toyota MR2 Audio Installation How-To Guide MKII Toyota MR2 Audio Installation How-To Guide . This page gives the details of a DIY aftermarket stereo installation in a MKII Toyota MR2. The installation is performed in a 1991 MR2 with the stock "Premium" system, but a lot of the information here is applicable to all MKIIs.