The following guide will assist in troubleshooting interior lighting problems with your Reatta. Other related articles on this website are:
Interior Light Problems - Troubleshooting
Circuit Color Codes For Floor Splices - '89
Wire Splice Repair

Door Switch Troubleshooting Guide:

1. Sit in drivers seat
   • Turn ignition to to the run position
   • Lower drivers window
   • Enter computer diagnostic mode
      
2. Go to BCM Inputs
    
3. Page down to B103
   • Display should say HI
   • Open driver's door slightly
     
     • Display should switch to LO if door ajar switch is working and back to HI when door is closed again
        
       
4. Page down to B105
   • Display should say HI with door closed
   • Open drivers door halfway or better   
     • Display should switch to LO
   • Re-close door
     
     • Display should go back to HI if door jamb switch is working
        
       
5. Page down to B106
   • Display should say HI
   • Reach through open window and lift the outside door handle
     • Display should switch to LO while handle is raised
   • Release handle
     • Display should say HI
        

Additional Information:

• B105 and B106 will do the same test on the passenger's door for the jamb and handle switches.
• If you need to test the door ajar switch on the passenger's side that is input B104

 

If problems are found with the above tests, wire splices under the carpet, beneath the drivers seat (hot wires 12 volts), and under the passenger seat (ground wires) should be investigated. Bad connections with the wire splices is a common problem with the Buick Reatta.