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Home >> Cadillac >> 1998 >> Seville STS >> Repair and Diagnosis >> Body & Frame >> Body, Cab Control Systems >> Body Control Module >> Diagnosis & Testing >> DTC B1318: Driver-Side Solar Sensor >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform BCM diagnostic system check. See BCM DIAGNOSTIC SYSTEM CHECK  . After performing system check, go to next step.
  2. Park vehicle outside, in a well lighted area. Turn ignition on. Using scan tool, display driver-side solar sensor and note sensor count value. Cover sensor with a dark material. If sensor count increases, go to next step. If sensor count does not increase, go to step 4).
  3. Clear DTCs using scan tool. Cycle ignition switch on and off for several times. Check DTCs. If DTC B1318 resets, go to next step. If DTC B1318 does not reset, problem is intermittent. Check for poor connections.
  4. Turn ignition off. Disconnect driver-side solar sensor connector. Turn ignition on. Check voltage between sensor harness connector terminals. See WIRING DIAGRAMS  . If voltage reading is 5 volts, go to step 8). If voltage reading is not 5 volts, go to next step.
  5. Check voltage between ground and sensor harness connector terminal "A" (Light Blue/Black wire). If voltage reading is 5 volts, go to step 9). If voltage reading is not 5 volts, go to next step.
  6. Check voltage between ground and IPM harness connector B2 (Light Blue/Black wire). If voltage reading is 5 volts, go to next step. If voltage reading is not 5 volts, go to step 10).
  7. Repair open or short in Light Blue/Black wire. After repairs, go to step 12).
  8. Replace driver-side solar sensor. After replacing solar sensor, go to step 12).
  9. Check if HVAC related DTCs are set. If HVAC DTCs are set, go to next step. If no HVAC DTCs are set, go to step 11).
  10. Check for proper terminal contact. Repair as necessary. If terminal contacts are okay, replace IPM. After repairs, go to step 12).
  11. Repair open or short in Yellow wire. After repairs, go to next step.
  12. Clear DTCs using scan tool. Recheck system operation.
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