Top 10 1999 GMC Sierra Questions & Answers

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stereo wiring diagram

We have a 1999 GMC sierra extended cab truck and I need a wiring diagram for this truck. We bought a new cd player and I need a diagram to make sure it is installed and set up right

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1999 GMC Sierra Truck Radio Wiring Guide
Car Radio Battery Constant 12v+ Wire: Orange
Car Radio Accessory Switched 12v+ Wire: Yellow
Car Radio Ground Wire: Black/White
Car Radio Illumination Wire: Brown
Car Stereo Dimmer Wire: Gray
Car Stereo Antenna Trigger Wire: N/A
Car Stereo Amp Trigger Wire: N/A
Car Stereo Amplifier Location: N/A
Car Audio Front Speakers Size: N/A
Car Audio Front Speakers Location: N/A
Left Front Speaker Positive Wire (+): Tan
Left Front Speaker Negative Wire (-): Gray
Right Front Speaker Positive Wire (+): Light Green
Right Front Speaker Negative Wire (-): Dark Green
Car Audio Rear Speakers Size: N/A
Car Audio Rear Speakers Location: N/A
Left Rear Speaker Positive Wire (+): Brown
Left Rear Speaker Negative Wire (-): Yellow
Right Rear Speaker Positive Wire (+): Dark Blue
Right Rear Speaker Negative Wire (-): Light Blue
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Posted on Apr 15, 2009

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1999 gmc sierra brake line diagram

i have this truck and i need to know where the brake lines go after they leave from under the hood and plug into the abs system... thanks you very much

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I would join autozone.com for free and they have most any diagram you will need for free for this vehicle

Posted on Sep 16, 2009

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where is the thermostat on a 2001 gmc sierra 1500 5.3l

looking for the thermostat?

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follow the top radiator hose towrds the motor. you'll see a hose clamp then on the otherside of that is the thermostat housing. there's two bolts holding it on. remove that and any other little brackets that are in your way and it's right there under that housing. Drain a few gallons out of your cooling system, remove housing, and pop old thermostat out. Clean the block and housing with some emery cloth, like $0.40 at auto parts store. (Note, that might not be needed if it's an o ring instead of a gasket. People at store can tell you for sure.) Once it's shiney, place new thermostat it put on new gasket and reinstall. If o ring, place o ring on thermostat and reinstall. top of cooling system, start truck, and keep topping off fluid till it's blowing good heat and not overheating.

Posted on Jan 02, 2009

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Heater on my 1999 GMC Sierra 1500 is not working,

Heater on my 1999 GMC Sierra 1500 is not working, i.e. fan runs, but no heat is produced, just luke-warm. Coolant is OK, but possible thermostat/water control valve malfunction? I can't see a water control valve, does this model have one?

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Posted on Nov 28, 2010

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abs light comes on and off randomly

i start it up and sometimes the light comes on right away and sometimes doesnt come on till i hit the break, but when the light is off and i hit the break pretty hard the pedal still pulses but just not like normal

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sounds like an intermittant fault in the ABS control valve, most likely one of the solenoid valves is sticking or out of self test range..

Posted on Feb 11, 2009

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bleeding air from 5.3l cooling system

replaced stat new fliud still overheating and no heat, highway driving no overheating, slow down to a stop will overheat ,rev up motor a few times and temp went down to normal for a short time, did blue chemical test on radiator did not change color, you know theres something to be said about no trk payments, this must be the opposite off that any ideas please

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it sounds like the temp sensor maybe bad. I actually just replaced one on a 2001 chevy doing the same thing. reading that it was running hot while stopped but fine while driving.

Posted on Feb 02, 2013

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need to know the diagram for the serpentine belt

need to know the diagram for the serpentine belt for a 99 GMC K1500 with a 5.7 Liter

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Fig. Accessory serpentine belt routing-4.3L, 5.0L and 5.7L engines without A/C

07e40b4.jpg

Fig. Accessory serpentine belt routing-4.3L, 5.0L and 5.7L engines with A/C

abe156c.jpg

Hope helped with this. (remember rated this). Good luck.

Posted on Feb 19, 2010

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1999 GMC Sierra fuel gauge is erratic

When ideling the fuel gauge will sometimes bounce. Also after filling the tank, the gauge will read empty and slowly move to full over the next 30 minutes.

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the fuel level sensor inside your gas tank might be defective
you need to drop the tank and check the level sensor

Posted on Apr 02, 2009

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Truck won't start right away when its hot.

1999 gmc sierra. Truck starts right away in the morning & when I get off of work. When I go to the gym after work & come out an hour & half later, I have to floor the accelerator to get it to start. I already changed the fuel pump & the fuel filter.

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U MAY HAVE A DEFECTIVE ENGINE COOLANT TEMP (ECT) SENSOR, U NEED A SCAN TOOL TO TEST THIS PART, THIS IS NOT THE SENDER FOR THE TEMP GUAGE THIS IS THE SENSOR THAT TELLS THE FUEL INJECTION COMPUTER HOW COLD OR HOT THE ENGINE IS, IF IT READS LOW THE SYSTEM WILL GET TO MUCH FUEL AND CAUSE A HARD START, DO U NOTICE ANY BLACK SMOKE WHEN IT FINALLY STARTS?

Posted on Feb 09, 2009

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1999 GMC Sierra 4WD -

1999 GMC Sierra 4WD - 5.3V8 Auto The 4 wheel drive is not working - (Auto push button type) I raised the vehicle on jackstands to see if the 4wd would engage. When all 4 wheels are off the ground the 4wd engages and all the wheels spin. But when I lowered the front wheels back to the ground, just the back tires spin and the driveline from the transfer case does not spin. I'm thinking somethings amiss with the transfer case - any insights would be great.

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Remove the transfer case and check it.internally. The procedure to remove the transfer case is as follows:-- crawl under the truck you will see the bolt pattern facing the front of the truck should be 15mm and they will be in a circle pattern between the transmission and transfer case .that is where you remove it.You will have to take the things off as to remove the transfer case. --- In some cases its noticed that transfer case motor gets faulty. In this system the transfer case motor must engage first, then a signal is sent to engage the front differential motor to engage the differential.  I think the problem is one of two items, either the front differential engagement motor is in-op or the transfer case motor is malfunctioning and sending false signals to the VCM (vehicle control module). If the front axle for any reason does not allow the front propeller shaft to spin while in the 2WD setting, the clutch pack in the transfer case will overheat because of the speed difference (slip) across the clutch pack between the stationary front driveshaft and the rotating rear driveshaft. the front axle, the transfer case should also be inspected for overheating by inspecting for burned fluid or a free rotating front driveshaft. In addition to correcting front axle concerns, necessary repairs should be made to the transfer case.  The auto locking hubs are not engaging properly and will need to be removed and spline sets checked for broken teeth on locking hub and locking shaft. Also check that the engaging spring inside the hub has enough tension to engage the hubs they may be broken. If the hub are all ok then you have a problem in the transfer box, where the 4WD lever is not meshing the transfer box properly. POSSIBLE THE ACTUATOR ON THE FRONT AXLE IS BAD ? YOU NEED TO SEE IF THE FRONT DRIVE SHAFT IS ROTATING WHEN THE 4 HI IS ENGAGED WITH OUT RUNNING YOUR SELF OVER IN THE PROCESS. 
 
THERE IS AN ACTUATOR ON THE FRONT AXLE AN ONE ON THE TRANSFER CASE, THE ONE ON THE TRANSFER CASE LOCKS THE DRIVE SHAFT IN AND OUT OF 4 HI & 4 LOW. THE ACTUATOR ON THE FRONT AXLE LOCKS THE FRONT DRIVE SHAFT IN.
Thanks. Keep updated for any more query. You can rate this solution and show your appreciation.

Posted on Jul 17, 2010

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