Repair 7

Proper headlamp performance is vital to the safe operation of a motor vehicle at night or in inclement conditions. If you have noticed the light output from your 2008 GMC Acadia headlights has diminished, or if one or more bulbs has burned out, it is time to replace them. Replacing the headlamps in your Acadia is an easy process that requires no tools. You will be rewarded with improved nighttime visibility in your vehicle after a small investment of time.

Instructions

1

Turn off the engine and turn the light selector switch to the off position.

2

Open the hood of the vehicle and prop open. Remove the electrical connector at the back of the headlamp assembly by depressing the plastic tab and pulling straight back. Some side to side movement may be needed if the connector is especially snug.

3

Remove the protective dust cap on the back of the headlamp by grasping it and pulling straight back. This cover keeps dust and moisture out of the headlight housing, make sure not to damage it.

4

Remove the metal retaining clip by pushing downward and swinging it away from the bulb. Remove the bulb by pulling it straight back, being caul not to strike it against the headlight enclosure.

5

Insert the new bulb into the headlight assembly and swing retaining clip into place.

6

Reinstall the dust cap and ensure it is well seated by running your finger around the circumference.

7

Reattach the electrical connector. Applying a small amount of silicone lubricant gel will ensure the connector does not corrode and is easy to remove the next time. Repeat all steps for the other headlight bulb if needed.

In 2004, General Motors recalled 581,394 sport utility vehicles, including certain GMC Envoy and Envoy XL models, due to windshield wiper problems that could reduce driver visibility in inclement weather and increase the risk of a crash.

Identification

Some GMC Envoys were built with defective windshield wipers. These wipers may turn on or off by themselves or stop working altogether. Some drivers may notice that their wiper pumps are continuously running, which can cause a short circuit and corrode the components within the wiper module.

Incidents and Investigation

Prior to the recall, in 2003, the National Highway Traffic Safety Administration (NHTSA) received 1,179 reports of windshield wiper failures in General Motors vehicles using the "family" design module (p/n 15171306 base, p/n 15171307 for vehicles equipped with rainsense automatic moisture sensitive wipers) that appeared in 2003-2004 model year GMC Envoy and Envoy XL vehicles. The NHTSA opened an investigation that prompted General Motors to recall these Envoys and other affected models in early 2004.

Repairs

Beginning on July 6, 2004, authorized GMC dealers began offering free repairs for Envoy wiper problems as part of the recall. Dealers need to patch the wiper module vent hole and inspect the internal components and electrical system for signs of water damage or corrosion. Contact GMC or the NHTSA with a vehicle identification number (VIN) to determine if your Envoy wiper problems are related to this recall.

You can adjust the rear brakes on your 2001 GMC Safari right in your home garage. This adjustment should be done periodically to lengthen the life of your rear brakes, to improve brake function, and to restore the function of the parking brake. This adjustment can be done in less than an hour and requires only a few basic tools that can be purchased from your local auto parts retailer. The adjustment procedure basically reduces the gap between the shoes and the drums, resulting in a higher brake pedal height and faster braking times.

Instructions

1

Put on work gloves and safety goggles.

2

Position two wheel chocks in front of each front wheel and two wheel chocks behind each front wheel to keep the car from moving while you work on it.

3

Put the floor jack under the rear differential and raise up the Safari until its higher than the jack stands. Slide the jack stands under the vehicles axle tubes next to each of the rear wheels. Lower your 2001 GMC Safari onto the jack stands.

4

Look for a rubber plug in the backing plate behind the wheel. Remove the plug.

5

Insert a screwdriver into the hole and rotate the star-shaped adjuster upward at the same time spin the rear wheel in a forward motion. Keep spinning the wheel and rotating the adjuster until you feel a slight drag on the wheel. Remove the screwdriver and reinsert the plug. Repeat this procedure for the other rear wheel.

6

Raise the vehicle up off the jack stands and move them out of the way. Lower the vehicle to the ground and remove the wheel chocks. Take the GMC for a test drive to make sure the brake pedal height is higher and that the parking brake is tighter, clicking a maximum of six notches when you engage it.

A 2002 GMC truck needs an OBD scan tool to clear the "Service Engine Soon" light. There is a computer within the vehicle called On-Board Diagnostics, or OBD, that monitors the various systems within the vehicle. It also keeps track of when you need routine maintenance. To keep the computer functioning properly so it keeps track of when the maintenance is due, you must use the OBD scan tool to read the code to find out exactly what type of servicing is needed. Then you simply use the tool to reset the light. Make sure you have the servicing performed before you clear the light.

Instructions

1

Locate the diagnostic connector port on the drivers side of the vehicle. It is located on the underside of the dashboard, between the center console and the steering column. Plug the OBD scan tool connector end into the diagnostic connector port.

2

Put the key into the ignition and turn it to the "on" position. This will power the scan tool on. Make sure you dont turn the key too far and start the engine.

3

Wait for the code to appear on the screen of the scan tool then press "Erase." If you are prompted by the question "Are you sure?," press "Yes." This clears the codes and you should see the "Service Engine Soon" light disappear from the instrument cluster. Unplug the scan tool and turn off the vehicle.

4

Turn the engine on and check to see that the "Service Engine Soon" light is still off.

GMC introduced the Yukon in 1992, and the Yukon Denali in 1999. The 2001 GMC Yukon was available with a 4.6-liter V-8 engine or a 5.3-liter V-8 engine in the base model SLE and SLT. The Denali was given a 6.0-liter V-8 engine from the factory. The oil in the 2001 Yukon should be changed every three months or 3,000 miles, or as indicated by the "Oil Life" indicator built into the instrument cluster. The type (not weight) of oil you use should depend on your driving styles and how many miles are on the vehicle.

Instructions

1

Lift the front of the Yukon with a jack. Place jack stands beneath the front subframe rails. Lower the truck onto the jack stands.

2

Lay beneath the front of the truck and slide yourself in a position to access the rear of the oil pan. The oil pan is the cast aluminum pan directly beneath the engine. Slide a drain pan beneath the oil pan.

3

Loosen the oil drain plug with an open-end wrench. Turn the drain plug out with your fingers. Allow the oil to drain into the drain pan for no less than three minutes. Insert the drain plug back into the oil pan. Tighten the plug to 25 foot-pounds with a torque wrench and socket.

4

Move the drain pan underneath the oil filter. The filter is located at the rear drivers side of the oil pan. Remove the filter with a filter wrench, then dispose of it into the drain pan. Wipe the filter mating surface on the engine with a clean rag. Remove any pieces of old gasket.

5

Open a fresh bottle of oil. Dip your finger tip in the bottle, then rub the fresh oil onto the gasket of the new oil filter. Thread new oil filter onto the threaded tube at the rear of the oil pan. Once the gasket makes contact, tighten the filter 3/4 turn more. Do not over-tighten it.

6

Lower the Yukon to the ground. Remove the oil fill cap on the engine. Add 6-quarts of 5w30 motor oil to the engine. Replace the oil fill cap when you are finished.

7

Start the engine and immediately inspect underneath the car for any leaks. Allow the engine to run for approximately 15 seconds, and turn it off. Wait two minutes for the oil to settle into the oil pan, and check the level with the dipstick. Add oil as needed to bring the level to the "Full" mark.

The thermostat in the 4.3-liter GMC Sierra pickup truck regulates operating temperatures within the engine to prevent overheating and premature engine failure. This is a big task for a very small, inexpensive part. When the thermostat stops regulating properly, you will notice the temperature gauge in the dash start to rise. You will smell the sweet odor of overheating coolant and your truck will eventually pour steam out of the engine bay. Changing the thermostat is a fairly easy job that shouldnt take you very long at all.

Instructions

1

Lift the hood and prop it open. Position a drain pan under the drain valve on the bottom of the radiator. Loosen the radiator cap. Open the valve with a pliers. Drain two gallons of coolant into a clean drain pan. Close the drain valve with the pliers.

2

Follow the upper radiator hose to the thermostat housing, behind the alternator.

3

Remove the two bolts that secure the housing to the engine. Hose removal is not necessary to remove the thermostat housing.

4

Lift the housing up and shove it and the hose out of your way.

5

Pull the old thermostat out of the engine and place the new one in. You must place the new one into the engine and orientate it in the same manner as the old one.

6

Lift the old gasket off the engine, wipe down the surface with a clean towel and place the new thermostat gasket into place.

7

Place the thermostat housing back on the engine and bolt it into place.

8

Remove the radiator cap. Pour the two gallons of fluid back into the radiator. Replace and tighten the cap. Close the hood.

Like many GM vehicles, the 1994 GMC Sonoma requires the removal of the interior door panel to replace the side view mirror. This task might intimidate many people but its not overly complicated. As a matter of fact, the first time a would-be home mechanic tries this and realizes how uncomplicated it is, he may desire to step up to bigger challenges. Replacing the side view mirrors on the Sonoma is less complicated than learning how to use them to back the truck up.

Instructions

1

Roll the window down all the way on the door with the mirror that needs replacing. If the Sonoma has power windows, turn the ignition to the "Off" position and remove the key from the ignition once the window is down.

2

Align the window crank removal tool (manual windows only) behind the length of the window crank. Pry the tool in between the crank and the door panel to unseat the retaining clip. The clip snaps over the internal section of the crank and will pop off with a slight spring force. Be careful not to let it fly off and get lost. Pull the window crank off its shaft once the spring is off.

3

Remove the two screws in the door pull cup with the Phillips screwdriver.

4

Pry the outside edge of the door panel (between the panel and the door frame) away from the frame with the trim panel pry tool. Work the pry tool to the bottom of the door panel and then to the other side to unseat all the plastic internal fasteners.

5

Push the door panel upward slightly to unseat the lip of the panel secured to the ridge of the door/window frame.

6

Disconnect the wire harness located on the inside of the door panel and then remove the door panel.

7

Disconnect the wire harness for the side view mirror (power mirrors only).

8

Remove the three retaining nuts attached the the side mirror studs with a ratchet and socket. Brace the mirror with one hand when removing the last nut, so the mirror does not fall and scratch the paint on the door.

9

Feed the wire harness (power mirrors only) through the access hole in the door frame to remove the mirror and harness from the Sonoma. For manual mirrors, simply remove the mirror.

10

Install the replacement mirror (manual or power) by reversing the removal procedure and then reinstall the door panel by reversing the removal procedure.

The GMC Jimmy is a mid-size sport utility vehicle made by General Motors from 1983 to 2005. The 2001 model is a second generation Jimmy, which has a 6-cylinder 4.3-liter engine with sequential fuel injection. This type of fuel injection uses a high-pressure fuel system requiring an electric fuel pump. The fuel pump in the 2001 GMC Jimmy is located within the fuel tank, so you must disconnect the fuel tank to replace the fuel pump.

Instructions

1

Disconnect the cable for the negative battery terminal with a socket wrench to prevent the accidental discharge of fuel. Open the filler cap for the fuel tank to relieve the fuel tank pressure. Wrap a shop rag around the pressure fitting on the inlet fuel pipe and install a pressure gauge to the pressure fitting. Place the bleed hose of the pressure gauge into a gasoline container and open the valve for the pressure gauge. Allow the fuel in the fuel system to drain into the gasoline container and disconnect the pressure gauge from the pressure fitting.

2

Drain the fuel tank by siphoning the fuel into a gasoline container with a hose. Support the fuel tank with a floor jack and disconnect the filler neck for the fuel tank with a socket wrench. Detach the skid shield and retaining straps from the fuel tank. Remove the electrical connections and fuel lines from the fuel pump. Disconnect the the mounting bolts for the fuel tank with a socket wrench and lower it from the vehicle with the floor jack.

3

Turn the locking ring on the fuel sending assembly counterclockwise with a spanner wrench. Remove the locking ring and disconnect the fuel sending assembly from the fuel tank. Separate the fuel pump from the fuel sending assembly.

4

Replace the seal around the opening in the fuel tank. Install the new fuel pump by performing steps two and three in reverse order. Tighten the mounting bolts for the fuel tank to 33 ft. lbs. with a torque wrench.

5

Connect the cable for the negative battery terminal with a socket wrench. Fill the fuel tank with fuel, start the engine and check the fuel system for leaks.

In 1996, GMC had 26 varieties of eight baseline models, all of which were pickup trucks, vans or SUVs. These models ranged in size from a quarter-ton to 1 ton, and though they had different motors, most of them had two oxygen sensors that screwed into the exhaust system and monitored the ratio of oxygen to burning fuel in the exhaust. The one closest to the motor (on the drivers side exhaust pipe near the manifold) is referred to as the "upstream" oxygen sensor, and the one near the catalytic converter is the "downstream" oxygen sensor. Buy a quality direct-fit after-market oxygen sensor and put it in yourself to save some money on labor charges.

Instructions

1

Drive the GMC onto the car ramps carefully until the front wheels center in the top pits. Turn off the engine, place the GMC in park or gear, and apply the parking brake. Place a wheel chock behind one of the rear tires.

2

Put on the safety glasses and grab all the remaining gear and crawl under the GMC on a creeper. Locate the oxygen sensor youre replacing by following the exhaust system from the front left Y-pipe near the manifold to the catalytic converter.

3

Follow the oxygen-sensor wire to the plug about 8 inches away and separate the plug using the flathead screwdriver to press in on the plastic clip lock.

4

Put the oxygen-sensor socket onto the ratchet and place the oxygen-sensor wire in through the slot of the socket on the side. Remove the oxygen sensor. If the sensor is stubbornly stuck, remove the socket and ratchet and light the hand torch. Heat the area of the exhaust pipe that surrounds the sensor to expand the metal and try again with the ratchet and socket until youre successful. If you had to use the torch, allow the exhaust pipe to cool down before you proceed.

5

Screw the new oxygen sensor into the porthole in the exhaust pipe. Most quality direct-fit sensors should have a light coat of anti-seize lubricant on the threads. Do not wipe that off, as it will make future removal and replacement procedures helpful. Tighten the sensor with the ratchet and socket, but be careful not to overtighten and strip the threads of the new sensor.

6

Reconnect the sensor wires at the plug connection. They will only fit one way.

7

Gather the tools and crawl out from under the GMC. Remove the wheel chock and lower the GMC.

Still considered a luxury item on most cars in the late 1990s, wireless entry devices, known as wireless key fobs, had yet to obtain the ubiquity they have today. As such, the technology and ease of maintenance was lacking, at the time. Reprogramming the fob for any 1997 GM, including the GMC Sierra CK1500, requires vehicle owners to have access to proprietary computer diagnostics equipment that plugs directly into a port under the vehicles dashboard to allow a technician access to the manual programming module.

Instructions

Instructions

1

Locate the computer access port under the vehicles dashboard, which is a plastic array of small holes aligned into two rows that has a bundle of wire running out of the back.

2

Power on the diagnostic computer and locate the socket for 1997 GMC. With the computer turned on, insert the socket into the port under the CK1500s dash.

3

Select "body control module" from the list of options on the diagnostic computer screen.

4

Select "Keyless Entry Code" then "Program" from sub menu. The screen should display a number that is unique to the vehicle.

5

Hold replacement fob next to diagnostic computer for 10 seconds, or until the computer returns "Complete."