Component Testing

2006 Chevrolet Suburban C2500, 6.0 USECTION Component Testing
WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Relay Test

  1. Ignition OFF, disconnect the RUN/CRANK relay.
  2. Test for 60-180 ohms of resistance between terminals 85 and 86.
    • If the resistance is not within the specified range, replace the relay.
  3. Test for infinite resistance between the following terminals:
    • 30 and 86
    • 30 and 87
    • 30 and 85
    • 85 and 87
    • If less than infinite resistance, replace the RUN/CRANK relay.
  4. Install a 20-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2.0 ohms of resistance between terminals 30 and 87.
    • If greater than 2.0 ohms, replace the RUN/CRANK relay.

Switch Test

  1. Ignition OFF, disconnect the stop lamp switch.
  2. With the brake pedal released, measure for infinite resistance between terminals A and B of the switch.
    • If resistance is measured, replace the switch.
  3. With the brake pedal released, measure for less than 1.0 ohm resistance between terminals C and D of the switch.
    • If resistance is not as specified, replace the switch.
  4. With the brake pedal applied, measure for less than 1.0 ohm resistance between terminals A and B of the switch.
    • If resistance is not as specified, replace the switch.
  5. With the brake pedal applied, measure for infinite resistance between terminals C and D of the switch.
    • If resistance is measured, replace the switch.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.