Driver's Multiplex Control Unit
Remove driver's underdash fuse/relay box and remove driver's multiplex control unit. See UNDERDASH FUSE/RELAY BOX under REMOVAL & INSTALLATION. Check connector and terminals for damage, corrosion or improper contact. Repair as necessary. If connections are okay, perform driver's multiplex control unit input test. See Fig 1. If all input tests are okay, substitute known-good driver's multiplex control unit and retest system. If problem is fixed, replace original driver's multiplex control unit.