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GMC Sonoma Problems

Why does the 4 wheel drive on a GMC Sonoma not engage? Why do the brakes on a GMC Sonoma feel squishy? How is the door panel removed? Why is the heater not working? The answer to these and other questions that Sonoma owners face are often difficult to find. Without this information identifying the cause of GMC Sonoma problems and the right solutions can be hard, if not impossible. Obtaining guidance and insights from Experts is a huge resource for vehicle owners.

Read below where Experts have answered a variety of questions pertaining to the GMC Sonoma and various problems.

What is preventing the 4 wheel drive of a GMC Sonoma from engaging and there is no drive in the front wheels?

Check the vacuum and the actuator itself in the front drive axel actuator that engages the front drive axel. First, check the solenoid that applies vacuum to the front actuator, it is located on the firewall by the wiper motor. It will have 2 vacuum hoses and an electrical connector with 2 wires attached to it. Start the vehicle and put the 4WD switch in the 4WD position. There should be a vacuum to the solenoid and to the hose coming out of it. If there is vacuum going in but not coming out the solenoid may need replaced. If there is vacuum coming out of the solenoid, then the hose should be checked for a leak. If there is no leak, the problem is with the actuator.

What will cause squishy brakes and one brake disc to overheat after changing the brake pads and rotors on a 1998 GMC Sonoma?

The squishy feeling of the brakes is due to air being present in the ABS system, which can only be removed by accessing the self-bleed of the ABS system using a scan tool. As for the overheated brake disc, it appears that the caliper is locked up. Drive the vehicle for a distance until the disc heats up. Remove the wheel and open the bleeder. If the caliper becomes free, the rubber line going to the caliper is the problem and it will need to be replaced. If the caliper does not break free, it could be defective and will need replaced.

What is preventing the heater from working on a 1999 GMC Sonoma when the fan and air conditioning work fine?

Check if the heater core has become restricted by starting the vehicle and allow the engine to completely warm up. Open the hood and locate the coolant heater hoses on the firewall that lead to the heater core. Both hoses should feel hot to the touch when the engine is running. If one hose is hotter than the other, that is a sign that the heater core is restricted. In many cases a back flush will clear the restriction. Remove the hoses from the heater core and use a garden hose to flush though both ends of the heater core. If this does not resolve the problem, the heater core may need to be replaced.

How to remove the right side door panel on a 1999 GMC Sonoma?

In order to prevent the retainer clips from breaking there is a special tool that must be used – a Door Trim Pad and Garnish Clip Remover. This can usually be rented from any ‘big chain’ auto parts store. Refer the diagram below and do the following:
• Remove the inside door handle bezel.
• If there is a window regulator handle, remove it.
• If the vehicle is equipped with power accessories, remove the power accessory switch mounting panel.
• Remove the trim panel armrest screws.
• Use the special tool to release the door trim panel retainers

The door trim panel can now be removed from the door.

Removing the GMS Sonoma right door panel

What is causing a GMC Sonoma to sporadically overheat after replacing the radiator and thermostat?

First check the water pump and the fan clutch, if these are good then a block test should be done. This will reveal the presence of any hydrocarbons in the system. If these are found, it could indicate that the head gaskets, head or block is cracked. Any of these will cause the intermittent overheating problem.

Like all trucks, the GMC Sonoma needs regular repair and maintenance to keep it in top running condition. But owners are often at a loss when it comes to choosing the right repair option. The insights and guidance of Experts is a valuable resource to GMC Sonoma owners facing problems.

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