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Chris (aka-Moose)
Chris (aka-Moose), Technician
Category: Chevy
Satisfied Customers: 47656
Experience:  16 years of experience
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Glow plugs on my Chevy duramax not working. Replaced glow

Customer Question

Glow plugs on my Chevy duramax not working. Replaced glow plugs replaced module. Tested glow plugs individually with test light and they work. Truck will not start unless block heater is plugged in or its warn outside. What else could it be?
Submitted: 1 year ago.
Category: Chevy
Expert:  Juan Crespo replied 1 year ago.

Which Duramax, VIN 1 or VIN 2?

Customer: replied 1 year ago.
Vin 2. LLY
Expert:  Juan Crespo replied 1 year ago.

Ok. You caught me on my way out. Give me a couple of minutes to reset. Be back in a bit...

Expert:  Juan Crespo replied 1 year ago.

OK. These are low voltage glow plugs that work based on pulse-width signals, so using a regular test light on any of these circuits might actually do more harm that good. Also, each of the glow plugs is monitored individually, so any fault detected with either one of them or with the controller should set a fault code. Any chance of getting this puppy scanned with something better than just a code reader?

Customer: replied 1 year ago.
I had it into the dealer they told me there was nothing wrong with the system. That's why I'm at a loss. They're best guess was the injectors all needed replacing but that doesn't explain why it starts fine when it's warm. What would I look for if I can get it scanned?
Customer: replied 1 year ago.
Also I would note that this problem occurred immediately after the headgaskets were changed. The new glow plugs were installed at that time.
Expert:  Juan Crespo replied 1 year ago.

I wish you had told me this before. At this point I don't have any information that could help you. I'll have to opt out so others may try. Please don't reply to this post until another expert responds or the site will cycle this request back to me.

Expert:  Chris (aka-Moose) replied 1 year ago.

Welcome, I'm Chris (aka Moose). Experts aren't employees / agents of Just Answer. We are independent service providers using the Site to sell their Expert knowledge to Customers. I strive to provide EXCELLENT 5 STAR service, let me know what's needed from me so your pleased.

  1. The previous tech has opted out. Would you like me to help?
Customer: replied 1 year ago.
You bet
Expert:  Chris (aka-Moose) replied 1 year ago.

Have you removed a glow plug and grounded it, turned the key on to see if the plug is getting hot or not?

Customer: replied 1 year ago.
I didn't leave it hooked up but I did take a few out and tested them with a battery and yes they got hot. That would have made more sense by keeping it hooked up though
Expert:  Chris (aka-Moose) replied 1 year ago.

Is that something you can try?

Customer: replied 1 year ago.
You bet. As soon as I get home I'll try it and let you know.
Expert:  Chris (aka-Moose) replied 1 year ago.

Super

Expert:  Chris (aka-Moose) replied 1 year ago.

Hello again Chris here,

1) When customers come to Just Answer the website and the experts want them to have a great 5 star experience.

2) We also want them to be so pleased that they come back for future needs.

3) I have the feeling you were not pleased with my help and or need me to help more. If so please do reply.

4) I have an option to upload diagrams, repair guides, find a repair facility, or call you if that would help.

Thanks Chris

Customer: replied 1 year ago.
Sorry Chris I haven't made it home yet to try your recommendation. I got sent out for work and It'll be another week before I can work on the truck again. I hope we can continue this conversation at that time.
Expert:  Chris (aka-Moose) replied 1 year ago.

Thanks for keeping in touch.

Customer: replied 1 year ago.
Hey Chris I tried what you suggested and no the glow plug didn't get hot. It didn't even warm up a little bit. What should I check next?
Expert:  Chris (aka-Moose) replied 1 year ago.

The glow plug controller powers the glow plugs. At the controller confirm the red wire is power. Pink power with the key on. Pink/yellow ground. If all pass then see if a scan tool can communicate with it. If so then your controller is to blame.

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Thanks Chris

Customer: replied 1 year ago.
I checked a few things
1. The glow plug controller plug I found power at the pink wire with key on only. No other wire gave a reading with the key off. Ground was ok. The single grey plug that connects to the controller shows 12v with key off.
2. Checked the voltage at the glow plug with key on and glow plug light on and it showed around 7v. I read that it should be around 4v not sure if that's true or not.So when this problem started the first thing I did was replace the controller and all the glow plugs. No codes came up and the gp light operates normal. Is there anything like a temperature sensor that would prevent the plugs from turning on?
Expert:  Chris (aka-Moose) replied 1 year ago.

Are there no codes stored?

Will your scan tool communicate with the glow plug control module?

Customer: replied 1 year ago.
My scan tool is just a simple code reader it can't communicate with the glow plugs. I pulled one of the electrical connectors off a glow plug to see if it would trip a code but it didn't. Next step is get or borrow a scan tool that can't communicate with the gp controller?
Expert:  Chris (aka-Moose) replied 1 year ago.

Thanks for the update.