20 Most Recent 2003 GMC Sierra Questions & Answers


No relay for guages. try slapping on top of dash to see if they come back on. They are controlled by a fuse and the body control module.

2003 GMC Sierra | Answered on Aug 29, 2019


try pulling the hot cold air mix nob straight off and tightening the nut at the base of the stem. Do the same thing with the vent selector nob.

2003 GMC Sierra | Answered on Jan 04, 2019


a/c is putting strain on the engine. could be a problem with the pump as only supposed to drop rpms by a 0.5%to 1% or you have a dirty idler and its not able to get enough air on idle, could even be a blocking air filter.

2003 GMC Sierra | Answered on Feb 21, 2018


An air leak in the induction pipe will do that.

2003 GMC Sierra | Answered on Jan 30, 2018


Are you located somewhere cold? some vehicles will not allow the evap to run its cycle under cold conditions, you shouldnt have to drive more than 180 miles, but you might have too. If you can take it to a heated garage and run it it might help

2003 GMC Sierra | Answered on Dec 21, 2017


Check the 10 amp pdm fuse in the cabin fuse panel.

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2003 GMC Sierra | Answered on Oct 31, 2017


Who looked at it ? Dealer ? Did the place's you had look at the vehicle hook up a factory scan tool an view data to door module's an the BCM ? Door ajar is a fuction of the door modules an the BCM - body control module . One of these modules is seeing an input that makes it think door is open .
The door ajar indicator system consists of the following components:
• The driver door module (DDM)
• The passenger front door module (PDM)
• The body control module (BCM)
• The instrument panel cluster (IPC)
• The driver information center (DIC)
• The driver door ajar switch
• The passenger door ajar switch
• The left rear door ajar switch
• The right rear door ajar switch
• The liftgate ajar switch

Driver Door Ajar And Passenger Door Ajar
The DDM and PDM receive a discrete input from the respective door ajar switch to indicate the status of the door. The DDM or PDM then communicates this status to the IPC via class 2 message. The IPC, upon receipt of this class 2 message, will illuminate the appropriate door ajar message in the DIC and also send a class 2 message to the radio to activate the door ajar audible warning when the following conditions are met:
• The transmission is removed from PARK
• The vehicle speed is greater then 8.05 km/h (5 mph)
Left Rear Door Ajar And Right Rear Door Ajar
The BCM receives a discrete inputs from both the left and right rear door and liftgate ajar switches to indicate the status of the doors and liftgate. The BCM then communicates this status to the IPC via class 2 message. The IPC, upon receipt of this class 2 message, will illuminate the appropriate door ajar message in the DIC and also send a class 2 message to the radio to activate the door ajar audible warning when the following conditions are met:
• The transmission is removed from PARK
• The vehicle speed is greater then 8.05 km/h (5 mph)

Could have DTC'S - diagnostic trouble codes . Looking at data paramiters on the scan tool tool would show what switch is faulty or what part is .

2003 GMC Sierra | Answered on Sep 05, 2017


To me...
it SEEMs your engine is not BREATHING...

Trouble Codes:
The REAL thing to do is get the codes read
(but since I also love to shoot from the HIP ... )

Lets just say YOU SHOULD GET YOUR
DIAGNOSTIC CODES READ... (DTCs).

Plenty of places do it for FREE...
My highest recommendation to you
would be a MUFFLER SHOP...

I would also advise getting your
(undisclosed) year, make & model...

On to the big PARTS HOUSES...
so you know your catalytic converter prices
before your local EXHAUST PALACE tacks
($$$$$)... because they've never seen a CAR
like yours... (supposed to be humor).

Go onto eBay, AMAZON & rockauto.com..
just to get your head ready to listen to your
neighborhood mechanics...

Rockauto
http://www.rockauto.com/en/catalog/gmc,2003,sierra+1500

Carnac the Magnificent

2003 GMC Sierra | Answered on Jul 24, 2017


Check the throttle position sensor it is used to adjust the idle when the engine is cold. The ECT switch by the thermostat outlet will sometimes send the wrong signal to the computer and tell the engine the temp is higher than what it is and that can also cause problems. Hope this helps. I would also check the cat and muffler and be sure the exhaust is not restricted. If it is then back pressure will not allow fuel to be drawn into the cyl. properly. Put your hand on the exhaust pipe and it can give you and idea if the exhaust is partially plugged or restricted. Hope this helps.

2003 GMC Sierra | Answered on Apr 29, 2017


It sounds like you could have a sway bar bushing failure

2003 GMC Sierra | Answered on Apr 09, 2017


Sounds like you need to replace the ignition switch and go from there.

2003 GMC Sierra | Answered on Dec 17, 2016


Well, it sounds like a ground problem to me. If a ground problem, it can cause some weird things to happen.
See the rear junction block, I'd check those grounds. Because those grounds are connected, ground wire is black, it looks like hunting a needle in a haystack. In the diagram, the top wires should be voltage and bottom wires ground. I guess you could try a separate redundant ground, at rear, for lamp/s? Click on the comment link.
2003-gmc-sierra-2500-rear-directions-jo14yp32an1pkgballcaecma-5-0.jpg

2003 GMC Sierra | Answered on Oct 21, 2016


There are four buttons on the steering wheel. a highway, a gas pump, a menu, and an arrow. Press the menu button until the display language is shown. Press the arrow button to change the language, press the menu button again when English is displayed.

page 3-50 in your owners manual


https://my.gmc.com/content/dam/gmownercenter/gmna/dynamic/manuals/2003/gmc/sierra_1500/2003_gmc_sierra_owners.pdf

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

2003 GMC Sierra | Answered on Oct 10, 2016


There are four buttons on the steering wheel. a highway, a gas pump, a menu, and an arrow. Press the menu button until the display language is shown. Press the arrow button to change the language, press the menu button again when English is displayed.

page 3-50 in your owners manual

https://my.gmc.com/content/dam/gmownercenter/gmna/dynamic/manuals/2003/gmc/sierra_1500/2003_gmc_sierra_owners.pdf

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

2003 GMC Sierra | Answered on Oct 10, 2016


This is a tough one because I don't know what would cause it to stick in there. My recommendation would be to use a pliers and pull and twist gently while the engine is heated up.

2003 GMC Sierra | Answered on Feb 02, 2016

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