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goodwrench9124, ASE Certified Technician
Category: GM
Satisfied Customers: 3432
Experience:  37 years of dealership exp. Ase Master Certified, GM Master Certified Tech. Awarded GM Top performer
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glow plugs going out in my 2007 3500 hd 6.6 duramax..replaced two

Resolved Question:

having problems with the glow plugs going out in my 2007 3500 hd 6.6 duramax. we replaced all of the them about six months ago. this past week i have to replace number 6.7.and 8 and about to replace 6 again which i just replaced two days ago. any ideas on what to look for. been told water but checked fuel filter and it was clean.
Submitted: 5 years ago.
Category: GM
Expert:  goodwrench9124 replied 5 years ago.
Hello and welcome, have you also got a check engine light on? and if so, was the system scanned for any trouble codes?
Customer: replied 5 years ago.
yes check engine light comes on only showing bad glow plug
Expert:  goodwrench9124 replied 5 years ago.
would you happen to know the trouble code number stored in the system?
Customer: replied 5 years ago.
no codes just shows bad glow plug. change glow plug reset code it shows nothing,
Expert:  goodwrench9124 replied 5 years ago.
ok, was looking for a trouble code number, but we will see if we can work around the trouble code for now. sorry for all the questions, but the more info I can get, the better I can understand the problem. did you replace glow plugs with OEM parts or aftermarket parts?
Customer: replied 5 years ago.
think they said P086 for the code i believe. and we are putting AC delco back in it
Expert:  goodwrench9124 replied 5 years ago.
Ok good deal. if i posted a couple of pictures, do you think maybe you can tell me which picture looks like your failed glow plugs?
Customer: replied 5 years ago.
sure got the one i took out here with me
Expert:  goodwrench9124 replied 5 years ago.
Great, hang loose a few and I will post a couple of pictures
Expert:  goodwrench9124 replied 5 years ago.

picture 1





picture 2




Customer: replied 5 years ago.

d0nt look like either 0f those there smooth just black soot

Expert:  goodwrench9124 replied 5 years ago.

Ok, there is some info on some common causes for glow plugs burning out. first of all, all the battery cables at batteries must clean and tight.


There are certain electrical concerns that may induce the glow plug to go open. If the glow plug system senses a certain electrical "noise" on the power feed, it could induce glow plug concerns. This electrical "noise" may be induced by jump starting, loose connections, disconnecting the batteries with the ignition in the ON position, or a battery charger being used during a module reprogramming event.

Complete all electrical circuit inspections and engine repairs as described


If a vehicle has been brought in with GPCM concerns or DTC P064C the GPCM battery positive cable will need to be inspected. Inspect for loose connections at the GPCM Connector (squeeze type terminal number C1 or X1) and at the power source/mega fuse. If the squeeze type terminal is damaged, the complete cable would need replaced. If the GPCM terminal is damaged, the GPCM would need replaced. Retorque loose mega fuse/power source connections using current SI specifications. The ignition voltage supply from the under hood fuse block must be consistent


GPCM stands for glow plug control module


basically if all connections look good, one of two issues, replacing the battery cable that attachs to the GPCM.

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