LBEC / MBEC 50 Amp Buss Fuse on 2004 Chevrolet Avalanche 1500

This fuse constantly blows. wehn a new fuse is in the battery is drained. any known problem / solution?

by in Winston Salem, NC on June 30, 2009
2 answers 1 comment
ANSWER by on July 01, 2009
The MBEC fuse feeds the right door and power seat circuit breakers which are located in the relay center on the firewall near the break pedal. You can try installing a new fuse AFTER pulling the circuit breakers. If the fuse still blows the problem is between the outside fuse box and the inside relay center. If the fuse does not blow then reinstall the circuit breakers one at a time and see what happens. If there is a fault in one of the circuits feed by the breakers they will trip to protect the circuit, they can however let enough current flow to blow the MBEC fuse. Be careful, if one of the circuit breakers is tripping it will be VERY HOT to the touch. I would suspect a shorted power feed wire under the drivers seat could be causing the problem on your Chevrolet Avalanche.
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ANSWER by on August 07, 2010
I had the same problem. MBEC 1 50A fuse blowing. Intermittently. Power seats became in-op and also both front and rear passenger windows would not go up. I found an Orange wire routing from the Underhood Fuse Block, where MBEC 1 is located, to the Center Instrument Panel Fuse Block which is located underneath the instrument panel, near your left foot, to the left of the steering column. The Orange wire was chaffed and rubbing against the bracket as it enters the Center Instrument Panel Fuse Block, causing a short to ground. Look there, you may find the problem.
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COMMENT by on October 17, 2010
Thanks for posting, I had the exact same thing on my 2008 silverado 4x4. Found problem thanks to your post.

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