This 2002 Pontiac Grand Prix GT came in with the complaint that the blower would not work on the lower speeds and that the high blower would work most of the time. A quick inspection of the system also found that when the blower did work on high speed it would have a delayed turn on of several seconds. From experience I wanted to check the ignition switch input to the HVAC CTRL fuse in the interior fuse box. The fuse box is located behind a panel on the right side of the glove box. Simply grasp the pull handle and pull as shown.
The inside of the cover should have a diagram of the fuse box like the one shown below. You have to rotate the diagram around to match the view of the fuse box. Circuit breakers up.
Doing this will lead you to the correct fuse which is the 20 amp fuse two up and two from the left as shown below. With the key switched on there was no power to the fuse. When testing for voltage with a test light or a voltmeter be sure to have the ignition and blower switches on. The fault should also be present. When the fault is not present the voltages may appear okay. This problem can come and go so test this circuit several times if needed. This is indicative of a faulty ignition switch which this body style seems to have a problem with. Pontiac, Buick and Oldsmobile.
Please click here to see how to replace the ignition switch.
If you don’t have a sunroof you can take the power from the fused side of the 20 amp sunroof fuse with a jumper. The only caveat is that the blower doesn’t shut off with the key but with the door and will not re-engage until the ignition switch is keyed again.
Yes. set your meter to 20 volts DC. Attach the black lead to a known good ground. Leave the fuse in place and place the tip of the red lead at the test point on the top of the fuse. Each fuse has two dimples that allow you to touch the circuit. Assuming that the fuse is good you can touch either dimple. Now have someone turn the ignition on and cycle the blower switch through the various speeds. A nominal 12 volts should remain present. If it varies greatly or disappears the ignition switch will be the likely cause.
Hi Sparky,
Got to this post from the Grand Prix ignition switch post. Please forgive a total noob when it comes to multimeters. What setting should I have the dial at when testing, and what exactly should I be looking for? Should I have the multimeter set to DC 20 volts, then put the red and black tips in the two holes where the fuse used to be? When I did that, I saw no change with the engine running and switching between all fan speed settings, off through 5. Does this mean the “fault is always present”, and thus I need to replace the ignition switch?
Thanks
Try the information at the following post addresses. You will need to copy and paste them. Although the posts refer to a Buick Century, they are both “W” bodies and test the same.
http://www.sparkys-answers.com/2009/03/2000-buick-century-blower-will-not-turn.html
http://www.sparkys-answers.com/2011/07/2002-buick-century-no-low-blower-speeds.html
your post covers everything except where to go if there is power at the fuse box,but the heater fan switch doesn’t work on 1 2 3 4 but does on five?