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Grounded wiring, problem found & solved

Discussion in 'GM Electrical Tech' started by ASK, Sep 19, 2011.

  1. ASK

    ASK New Member

    Everyone with a GM truck should look under the driver side dash, just above the left side of the floorboard, where there is a wire terminal box that is attached with a 1 inch or so tall plastic nut and remove that cover. After removing the nut, compress the two locking tabs on the sides near the top and rotate the top of the terminal block towards you. The bottom has tabs that can then be lifted out and the terminal block can then be pulled forward out of the way.

    Behind this terminal block is the wire bundle that goes from the driver side interior fuse terminal thru the firewall to the underhood fuse terminal. This wire bundle is probably an inch or so in diameter. It has a plastic type wire loom around most of it EXCEPT for the last 5 or 6 inches where it goes thru the firewall. There is a rubber type seal thru the firewall. The parking brake mechanism has an internal spring that has a STEEL HOOK that penetrates thru the steel housing. This spring end is slightly flattened for strength and produces a nice EDGE that can CUT THRU the tape only wrap on the wire bundle. In my case it was the DARK BLUE right turn signal wire that was RUBBED THRU and finally WENT TO GROUND.

    After isolating this wire bundle, I installed a new 20amp fuse in the TURN SIGNAL drivers side fuse block and tried the right turn signals and the hazard flasher. I was satisfied that this was the problem and the solution. I took a 2 inch length of radiator hose and split it length wise, placed it over the wire bundle and tywrapped it. This wire bundle can "move around" during normal driving and it took 10 years to finally rub thru. After many false alarms and blown fuses I finally found the cause and everything now works fine again.

    Anyone having any type INTERMITTENT fuse blowing or failure of some other type electrical parts should FIRST LOOK AT THIS AREA as the possible source. I could have saved the cost of a multifunction switch, several relays and flashers and a whole bunch of fuses along with about 12 hours of time and frustration​
    Last edited by a moderator: Sep 22, 2011
  2. rodder98

    rodder98 New Member

    Thank you

    I have an intermittent problem now, with the heater fan sometimes working and sometimes not. So, I will definitely check this.
  3. 99'HEARTBEAT

    99'HEARTBEAT Moderator Staff Member ROTM Winner Platinum Contributor 1000 Posts

    What year and model is your Vehicle??.....
  4. zigger215

    zigger215 New Member

    The heater problem could be something else. From silverado models from 03-07 (classic) the speed control module (resistor module) goes bad fairly often in these trucks. It will cause intermittent blower motor issues. It's funny that got brought up now, myself and the shop I help out are battling lithia right now over this issue, first it happened to acouple customers and then not even a week later I started having the issue. Ignorant service techs are blaming auto starts (lazy, clueless d*cks). Right now it looks like GM just released a bad batch of new resistors so it's hard to tell when we will be able to actually resolve the issue. There is a rumor that you have to replace the blower motor with the resistor, haven't confirmed this yet.
  5. 99'HEARTBEAT

    99'HEARTBEAT Moderator Staff Member ROTM Winner Platinum Contributor 1000 Posts


    From what you have mentioned, yes the problem is Most likely with the Blower Motor Resistor, once again as you mentioned the problem with this is on the 2003" to 2007" Trucks and other G.M./Chevy Vehicles.....G.M. Does have a Special Coverage Adjustment Regarding this issue, Below is a G.M. Service Bulletin that goes into Detail about this Problem with the Blower Motor Resistor,

    In short the Coverage is the Following,
    Special Coverage Adjustment,.......This Special Coverage covers the condition described below for a period of 10 years or 150,000 miles (240,000km) whichever occurs first, from the Date the Vehicle was Originally Placed into Service.......Regardless of Ownership.

    Dealer are to install a New Blower Module Connector......and the Repair will be made at No Charge to the Customer.



    G.M. SERVICE BULLETIN
    Special Coverage Adjustment
    Bulletin No.: 11046

    Date: April 07, 2011

    Subject: 11046 - Special Coverage Adjustment - Heating, Ventilation, and Air Conditioning Blower Not Fully Functional on All Blower Speeds, Inoperative, or Runs Continuously with the Ignition Off

    Models:
    2003-2006 Chevrolet Avalanche, Suburban, Tahoe
    2003-2007 Chevrolet Silverado
    2003-2006 GMC Yukon, Yukon XL
    2003-2007 GMC Sierra
    Equipped with Manual HVAC (CJ3) or Heavy Duty Heater (C42)

    Due to part availability, owner letters will be released in phases starting with older model year first. Owners for model year vehicles not included in first phase owner mailing will receive an owner advisory letter.

    The letter will inform the customer that parts are not yet available and that another letter will be sent to them when parts become available. A copy of this letter will be attached to the dealer message announcing this bulletin.

    In the meantime, if a customer brings their vehicle to the dealership with the condition described in this bulletin, repair the vehicle using the parts called out in this bulletin.

    Condition.......On some 2003-2006 model year Chevrolet Avalanche, Suburban, Tahoe; GMC Yukon, Yukon XL; and 2003-2007 model year Chevrolet Silverado and GMC Sierra vehicles equipped with a manual heating, ventilation, and air conditioning (HVAC) system (CJ3) or heavy duty heater (C42), the interface between the electrical terminals of the relay Resistor Module and the Wiring Connector that powers the module may be incapable of conducting higher current levels for sustained periods of blower motor operation. In addition, moisture and other contaminants may enter the fresh air intake plenum and contact the internal circuit of the module or corrode the terminals. Either of the above may cause the relay resistor module or wiring connector to overheat, resulting in one or more of the following symptoms:

    - The HVAC blower may not function on certain or all blower speed settings
    - A burning plastic smell or smoke may be present in the vehicle
    - The HVAC blower may run continually with the ignition in the OFF position


    IN VERY RARE events, if the above Symptoms are Ignored......A FIRE Could Occur.


    Special Coverage Adjustment,.......This special coverage covers the condition described above for a period of 10 years or 150,000 miles (240,000km) whichever occurs first, from the Date the Vehicle was Originally Placed into Service.......Regardless of Ownership.

    Dealer are to install a New Blower Module Connector......and the Repair will be made at No Charge to the Customer

    Important.......For vehicles covered by Vehicle Service Contracts, All eligible Claims with repair orders on or after April 8 2001 are covered by this special coverage and must be submitted using the labor operation codes provided with this bulletin. Claims with Repair orders prior to April 8 2011 must be Submitted to the Service Contract provider.

    Vehicles Involved,
    Involved are certain 2003-2006 Chevrolet Avalanche, Suburban, Tahoe; GMC Yukon, Yukon XL; and 2003-2007 Model year Chevrolet Silverado and GMC Sierra Vehicles equipped with a Manual HVAV (CJ3) or Heavy Duty Heater (C42)

    Inprotant,
    Dealers are to confirm vehicle eligibility prior to beginning repairs by using the Applicable Warranties section in the Global Warranty Management system.


  6. zigger215

    zigger215 New Member

    Some 03-07 are outside this coverage, it's based on the plant where your truck was assembled.

    GM also announced that the new resistors released from certain factories are immediately bad. Also with the new resistors that work, it is required you change your blower motor as well as your old blower motor will not work affectively with the new resistor
    Last edited: Jan 11, 2012
  7. 99'HEARTBEAT

    99'HEARTBEAT Moderator Staff Member ROTM Winner Platinum Contributor 1000 Posts

    On the Coverage, I have not heard that the Coverage is Based off of where a Truck was Assembled, nor does it express this in the G.M. Bulletin above??

    Once again I have not heard and/or seen the information from G.M. that.....
    it is required you change your blower motor as well as your old blower motor will not work affectively with the new resistor,

    I've replaced my Blower Motor Resistor and the Blower Motor Resistor Wiring Connector Only....in my Truck a couple yrs back.....as did a couple of my Buddy's and many others, I can only express on my truck and my Buddy's Trucks, to date no issue's and/or problem's.....with the replacement of the the parts I've mentioned above......If you have up-dated Information from G.M. Regarding this issue with the Blower Motor not working with the New Resistor......please post-it as it may be able help other member's regarding this issue.........:glasses:
  8. zigger215

    zigger215 New Member

    Lol I'm trying haha. I'm not asking about this info. I KNOW about it. I have a TSB through GM because of the work I do. There is a refreshed version of the resistor module and it is recommended to change the blower motor with this particular version of the module. However, GM made a mistake when producing the new resistors and now they recalled the latest batch number back. Also certain GM trucks are CERTAINLY excluded from the recall (my 04 being one of them). Lol no rumor mill hear, this is info I pulled from my TSB this morning. I've replaced hundreds of blower motor speed control modules (aka resistors)
  9. rodder98

    rodder98 New Member

    Could you please tell us the TSB number? I think many of us would be very interested in reading it.
    I am having a very similar problem with a '99 GMC Sonoma.
    I know it is the smaller truck, but maybe the same problem happens.
    Since it the fan runs intermittently, it is driving me nuts. I just wish the issue would fail completely so I can find it.
    Thanks for sharing the info you have.

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