my Cadillac Escalade T1XX (2021-Present) won't start but lights are on, what's wrong?

Symptoms

• Dashboard lights are on but engine does not crank
• No clicking sound when the ignition is turned
• Power accessories (radio, windows) function normally
• Possible security system warning light illuminated
• Battery voltage may be low or insufficient

Diagnostic Steps

1. Check the battery voltage using a multimeter to ensure it is above 12.4 volts.
2. Inspect battery terminals for corrosion or loose connections.
3. Test the starter relay by swapping it with another identical relay in the fuse box.
4. Scan for diagnostic trouble codes (DTCs) using an OBD-II scanner.
5. Verify the operation of the ignition switch by checking voltage at the starter solenoid when the key is turned.
6. Inspect the fuses related to the starting system for any blown fuses.

Solution

1. Preparation

• Gather tools: multimeter, OBD-II scanner, socket set, and a torque wrench.
• Ensure the vehicle is in park (or neutral) and the parking brake is engaged.

2. Battery Inspection and Replacement

• Check Battery Voltage:
  • Use a multimeter to measure the battery voltage.
  • If below 12.4 volts, charge or replace the battery.
• Clean Battery Terminals:
  • Disconnect the negative terminal first, followed by the positive terminal.
  • Clean the terminals and cable ends with a wire brush and a mixture of baking soda and water.
  • Reconnect terminals, ensuring they are tight.

3. Starter Relay and Fuse Inspection

• Check Starter Relay:
  • Locate the starter relay in the fuse box.
  • Swap it with another identical relay to test functionality.
• Inspect Fuses:
  • Check all fuses related to the starting system (refer to the owner’s manual).
  • Replace any blown fuses with the same amperage rating.

4. Ignition Switch and Starter System

• Test Ignition Switch:
  • Use a multimeter to check for voltage output at the ignition switch.
  • If there is no voltage, the ignition switch may need replacement.
• Inspect Starter Solenoid:
  • If the ignition switch is functioning, check voltage at the starter solenoid when the key is turned to the start position.
  • If no voltage is present, further investigate wiring or the ignition switch.