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.