Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1997CHEVY EXPRESS G3500, VAN CARGO, 6.5 FREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 53 (ENGINE COOLING FAN)SCAN TESTERCOOLING FAN CIRCUIT DIAGNOSIS (2 OF 2)NOTES
1997 Chevrolet Chevy Express G3500, Van Cargo, 6.5 F
COOLING FAN CIRCUIT DIAGNOSIS (2 of 2): Notes
1997 Chevrolet Chevy Express G3500, Van Cargo, 6.5 FSECTION Notes
WARNING: This page is about a different car, the 1995 Pontiac Trans Sport, 1995 Oldsmobile Silhouette, and 1995 Chevrolet Lumina APV. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Test numbers refer to numbers on diagnostic charts.
- Battery voltage should be available at terminals No. 85 and 87 of each relay when ignition is on.
- This checks PCM's ability to ground circuits No. 335 and 473. SERVICE ENGINE SOON light should be flashing at this point. If light is not flashing, see the G-TESTS W/CODES article in the ENGINE PERFORMANCE section.
- This tests if cooling puller and pusher fan relay (circuits No. 409 and 532) are open. Jumpering relay harness terminals No. 30 and 87 by-passes relay, which should cause fans to run if motors and wiring are okay.
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:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.