1999 Blazer - "Service 4WD" light on

phil_debol · 11-29-2004, 09:08 AM

Hi All,

My "Service 4WD" light has come on. Currently, when I turn the ignition switch on, there is no clicking in the passenger side kick panel and the 4WD switch lights on the dashboard barely flash for a nano-second and go off completely as I'm turning the ignition on. A GM mechanic ran the diagnostics and said it indicated an intermittent ground and that it could be a loose ground somewhere or a motor on the transfer case could be bad.

Anyone have any ideas as to go about finding the problem?

Thanks.

Jimmy-James · 12-04-2004, 06:59 PM

So...when the truck is running the light it off?

phil_debol · 01-10-2005, 10:40 AM

Quote: Originally Posted by Jimmy-James

So...when the truck is running the light it off?

Yes, all 4wd lights are off, but the service 4wd light is on. I have the 4 button switch. I replaced the transfer case motor but it didn't fix the problem. The vacuum is working, pulling the accuator in and out. The control relay box is not clicking when I turn the ignition switch on. The 4wd lights should come on and the relay should click when I turn the ignition on. But nothing is happening right now.

phil_debol · 01-10-2005, 10:41 AM

Scott01 · 01-10-2005, 09:54 PM

Sounds like the control box is dead.

11-29-2004, 09:08 AM	#1
phil_debol Registered User Age: 39 Join Date: Nov 2004 Posts: 5 Location: User is: OffLine	99 Blazer - "Service 4WD" light on Hi All, My "Service 4WD" light has come on. Currently, when I turn the ignition switch on, there is no clicking in the passenger side kick panel and the 4WD switch lights on the dashboard barely flash for a nano-second and go off completely as I'm turning the ignition on. A GM mechanic ran the diagnostics and said it indicated an intermittent ground and that it could be a loose ground somewhere or a motor on the transfer case could be bad. Anyone have any ideas as to go about finding the problem? Thanks. Last edited by phil_debol : 11-29-2004 at 05:55 PM.
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12-04-2004, 06:59 PM	#2
Jimmy-James strip rat Join Date: Nov 2003 Posts: 177 Location: Northeast Indiana User is: OffLine	Re: 1999 Blazer - "Service 4WD" light on So...when the truck is running the light it off?
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01-10-2005, 10:40 AM	#3
phil_debol Registered User Age: 39 Join Date: Nov 2004 Posts: 5 Location: User is: OffLine	Re: 1999 Blazer - "Service 4WD" light on Quote: Originally Posted by Jimmy-James So...when the truck is running the light it off? Yes, all 4wd lights are off, but the service 4wd light is on. I have the 4 button switch. I replaced the transfer case motor but it didn't fix the problem. The vacuum is working, pulling the accuator in and out. The control relay box is not clicking when I turn the ignition switch on. The 4wd lights should come on and the relay should click when I turn the ignition on. But nothing is happening right now.
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01-10-2005, 10:41 AM	#4
phil_debol Registered User Age: 39 Join Date: Nov 2004 Posts: 5 Location: User is: OffLine	Re: 1999 Blazer - "Service 4WD" light on bump
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01-10-2005, 09:54 PM	#5
Scott01 ZR2 member Age: 37 Join Date: Mar 2002 Posts: 1,903 Location: Northeast Ky User is: OffLine	Re: 1999 Blazer - "Service 4WD" light on Sounds like the control box is dead.
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