GM Service Manual Online
For 1990-2009 cars only
  1. Inspect circuit breakers #2, #6, #12 and #13 to determine if any circuit breaker is open. If an open condition exists, locate and repair the overload condition and replace the circuit breaker.
  2. Inspect ground G105 to assure that it is clean and tight.
  3. Inspect for broken (or partially broken) wire inside the insulation. This condition could cause system malfunction but prove to test good in a continuity or voltage test with the system disconnected. These circuits may be intermittent or resistive when in operation. If possible test for a voltage drop when the system is operational.
  4. Inspect for proper installation of aftermarket electronic equipment which may affect the integrity of other systems.