Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
Hi There, I'm Clayso a certified master automobile technician with 30 years of automotive repair and diagnostic experience.
From your description to pop a 40 amp fuse basically takes a direct short to ground. Fuse #49 goes directly to the starter relay in the underhood fuse box. Fuse #49 also goes to connector C200 under the steering column then to the ignition switch. There is no mention if anyone looked under the underhood fuse box for any corrosion build up on this affected circuit CKT 142 as seen in the link below.
Fuse 49 Circuit 142
The underhood fuse box being above the front tire it's possible for anything coming up from the tire and getting into the bottom of the fuse block. Let me know if fuse 49 pops during cranking or operating the vehicle.
Also make sure you're not using a bulk pack of fuses from Harbor Freight. GM issued a service bulletin several years ago concerning these fuses that they are inferior and will not pop at the specified ratings.
I hope this information is helpful. If you have any questions let me know. You can reply back to me through this thread at any time.
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