Owner's Problem Description
The owner of a 1999 Oldsmobile Intrigue reported that the power windows are not functioning. They checked the window fuse, which appeared to be good, and also confirmed that the vehicle does not have a sunroof. Despite these checks, there is no power at the master switch connector, indicating a potential issue in the wiring or circuit. The owner is seeking further diagnostic assistance.
Professional Technical Analysis
The 1999 Oldsmobile Intrigue is equipped with a power window system that relies on a master switch to control the windows. With the reported issue of non-functioning windows, initial checks revealed that the window fuse is intact, which typically carries 30 amps for the power window circuit. The absence of power at the yellow wire on the master switch indicates a disruption in the circuit, possibly from the circuit breaker located behind the right side of the dash. Given that the owner confirmed no power at the master switch connector, the diagnosis should focus on tracing the circuit from the breaker to the switch. It's essential to verify the integrity of the wiring and ensure the master switch is properly grounded. A multimeter should be used to check for continuity along the yellow wire, with expected voltage readings of 12V when the ignition is on. The vehicle's condition suggests that previous repairs may not have addressed underlying wiring issues, which are common in vehicles of this age due to corrosion or wear. The primary concern is ensuring the safety of the electrical system to prevent potential short circuits or further electrical failures.
Possible Causes
Most common causes (ordered by frequency):
- Power Window Circuit Breaker Failure: The circuit breaker, which is typically rated at 30 amps, may have failed or lost connectivity, preventing power from reaching the master switch. This can occur due to thermal overload or corrosion at the contacts. Testing the circuit breaker for continuity is crucial, and it should provide a stable connection when tested. If found defective, replacement with an OEM or quality aftermarket part is recommended. The part number for the circuit breaker is typically GM P/N 12135819. - No power at the master switch connector, continuity failure in the circuit breaker.
- Master Switch Grounding Issue: The master switch may not be grounded properly, causing an open circuit condition. This can occur due to corrosion or damage to the ground connection. Verifying the ground integrity at the master switch is essential, with expected resistance values below 5 ohms. If the grounding is found to be compromised, cleaning the contact points and ensuring a solid ground connection is recommended. - No power at the master switch with proper grounding confirmed, indicating potential open circuit.
- Wiring Harness Damage: The wiring harness between the circuit breaker and master switch may have sustained damage due to wear, rodents, or environmental factors. Inspecting the harness for visible signs of wear, frayed wires, or corrosion is necessary. Testing continuity along the harness with a multimeter will help identify any breaks or shorts. Repairing or replacing damaged sections is crucial for restoring functionality. - Visible wear or damage to the wiring harness observed, continuity failure in sections of the harness.
Diagnostic Steps
Professional Diagnosis Process
Follow these systematic steps to accurately diagnose the issue. Each step builds on the previous one to ensure accurate diagnosis.
- STEP 1 - Visual Inspection: Start with a thorough visual inspection of the wiring harness, circuit breaker, and master switch. Look for any signs of wear, corrosion, or damage. Pay close attention to the ground connections and ensure that all connectors are secure and free of contaminants.
- STEP 2 - Continuity Testing: Use a multimeter to test for continuity in the circuit breaker and between the master switch and the breaker. Expected continuity should be confirmed in both directions with resistance values below 5 ohms. If continuity fails, further tests should be done to isolate the break.
- STEP 3 - Voltage Supply Check: Test the voltage supply at the circuit breaker with the ignition on. The voltage should read approximately 12V. If voltage is absent, trace back towards the battery and inspect for any issues along the power supply line.
- STEP 4 - Ground Verification: Confirm the ground connection at the master switch using a multimeter by measuring resistance. Values should be below 5 ohms. If high resistance is detected, clean the ground point and ensure a solid connection.
