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  1. #1

    Default Keep Blowing the MBEC 1 50 Amp Fuse


    I am new to the forum but need to get my problem resolved. I own a 2007 Chevy 2500HD Duramax, 4x4, CC, SB Vehicle Ident No. 1GCHK23D37F130823. For the past 2 1/2 years the truck periodically blows the MBEC 1 50 amp fuse that is in the Fuse box under the hood. When blown the two passenger side window, both power seats and seat heaters become inoperative. When replaced, the fuse will last between 1 day to 6 months. Have taken it to two different Chevy Dealerships, once while the fuse was blown and once not. Neither dealership could find a cause.
    Do you have any suggestions as to what would be causing this problem and/or how to correct it?

    Thank you,
    Daniel Spencer

  2. #2


    My friend has a 2004 Silverado and had the same problem. I found a wire rubbing on the edge of metal grounding out left of the brake pedal by the parking brake pedal. It was on a white plug coming out of the mbec that has a cover on it. I would suggest looking around under the dash for wires rubbing on metal edges

    - - - Updated - - -


    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors,
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  3. #3


    Thanks Pikey, I certainly will check that area out real through. What made you look in that area?

  4. #4


    Your issue is definitely intermittent (well duh ). Unfortunately, that makes it much harder to diagnose unless it just happens to be broken right when you're diagnosing it. I would also agree with Pikey in that I'd look for cut or chafed wires. Does this issue mainly crop up during certain weather events such as hot, cold, wet, etc? That will also help you get some insight as to the source of the issue.

    1991 Chevy Suburban 1/2 ton 2WD w/ chevy SBC 350-3/4 ton drivetrain upgrade w/4.10 gears 200K miles
    2005 Saturn ION-2 Stock 277K miles
    1982 Bronco, 1993 Bronco (sold), 1971 M35A2 Deuce and a Half

    There are 10 kinds of people, those who understand binary, and those who dont...

    Remember kids, the only difference between screwing around and science is writing it down- Adam Savage

  5. #5


    There don't seems to be any pattern to weather conditions. We have on several occasions reframe from using the seats or windows for an extended period only to try the window and find it blown again. Can't find any common denominator.

  6. #6


    Past experience stories can be a big help with this type of problem. Like @Pikey, and his helpful story, I had a friend with a similar problem, in his case, there was a wire grounding under the power seat.

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

  7. #7


    Your Right! That's the problem... way too many places that it could be grounding out. I read some where that one of the electrical motors could be arching. The possibilities are endless. Mean while I have a wife who can't drive without re-adjusting the seat and with winter coming on....can't turn her seat warmer on.....not a happy camper. I will try and check out Pikey's theory tomorrow.

  8. #8


    I know that this might sound strange, but when I was looking for my friends issue, I started running my hand over spots where wires went across metal corners, I cut myself on the spot where I found his rubbing.

  9. #9


    Does this mean I need to be willing to sacrifice my blood to find this short? Maybe a little!

  10. #10


    Yep!! It's all for the good of your Chevy! This problem has one advantage, your wife can not drive your truck, but it is outweighed by the disadvantage of not being able to turn on her heated seat.

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