This 2002 Buick Century came in with the complaint that the lower blower speeds do not work. This Century has manual air conditioning controls. I have been down this road many times and it is just a faulty blower resistor. I will give actual testing information later, but for now I am just going to concentrate on changing the resistor.
First of all the blower resistor is located under the passenger side of the dash. There are a total of three push pins that need to be removed. Two along the leading edge.
One underneath, towards on the left side as shown below.
Once the panel is loose the courtesy light needs to be removed if present. A simple left turn and it comes right out. Remove the panel and position the light out of the way so that it will not burn you or anything else. If you are smarter than me, you will probably pull the fuse or bulb.
The blower resistor is located beyond the blower motor in the picture below. It has the seven wire, multicolored harness attached to it.
In the next picture I show the connector that goes to the blower motor. It has a locking tab that has to be depressed with a small screwdriver or other device. Then the connector can be wiggled out of the blower motor receptacle.
The seven wire connector has a latch on the outside of it, that has to be pulled slightly away from the resistor body, while the connector is pulled straight down. Tuck the harness out of the way while you continue to work.
Now using a 5.5 mm socket and ratchet, remove the leading screw from the blower resistor as shown below.
The next picture shows the removed screw, and the reason I make a point of showing it to you, is so you will have an idea of how much the screw would move with one full turn (the space between the threads).
Now bring the harness connector for the blower motor, that is attached to the blower resistor assembly, around the larger harness as shown below.
Now for something that is a bit unorthodox for me. With your hand or a pair of pliers, pull the harness towards you, until the resistor pulls loose of the two front mounting screws. For many years I fought with sockets, swivels and extensions to try and remove the two front screws.
There are two slots for the forward mounting screws as shown in the picture below. Do not pull it with the intent of moving it a great distance. Just a firm pull to let it move about a quarter to a half an inch. If you pull too aggressively, you will wind up having to pull the broken pieces of the resistor board, out of the main a/c housing.
If you look closely you will see the two forward mounting screws.
The new resistor on the left and of course the old resistor on the right. Notice that the interior resistor parts have been redesigned and are much heavier.
It is a little hard to see, but if you double click on the picture below you will see that I am using an open end wrench to slightly loosen the forward mounting screws. They only need to be loosened 1/4 to 1/2 of a turn. Doing this, while unorthodox, will allow the resistor just enough room to slide under the heads of the screws.
There should be just a slight bit of resistance as you push the resistor front edge under the two mounting screw heads. If it feels too easy, pull the resistor back out and tighten the screws slightly. If it seems like to much force will be needed, loosen the screws just a little bit more. It should feel like the detent when you close a tool box drawer. Now install the single screw closer to you and connect all of the wiring. When connecting the wiring, be sure to properly align the connectors and a straight and direct force to push it into place. You want to avoid wiggling, while removing and installing these connectors.
If you need one of these resistors please click here.
If you want to test the circuits coming in, it will be as follows:
- Terminal “A” Tan = Speed 2, power through blower switch from Low Blower fuse, 20 amp, Ignition
- Terminal “B” Yellow = Speed 1, power through blower switch from Low Blower fuse, 20 amp, Ignition
- Terminal “C” Purple = Speed 4, power through blower switch from Low Blower fuse, 20 amp, ignition
- Terminal “D” Lt Blue = Speed 3, power through blower switch from Low Blower fuse, 20 amp, Ignition
- Terminal “E” Black = Blower system, ground at all times
- Terminal “F” Small Orange = Speed 5, power through blower switch from Low Blower fuse, 20 amp, Ignition
- Terminal “G” Large Orange = Speed 5, Constant power from High Blower fuse, 30 amp, Battery
Fuses are located in the interior fuse boxes.
Thank you SO much ! I would NEVER have grabbed that wire after taking out the front screw, and YANKED that thing out. (And, I never would have found the rear two screws!) But, it worked like a charm. THANK YOU for the very detailed write up.
Thank you very much. I just did my 2003 Century following this instruction. It took me almost 90 minutes. the most difficulet part is to get the old one off.Thanks again.
worked like a charm on my 03 Century, Thank you very much!
Great how to, I don’t I would have been able to do it if it weren’t for the trick getting it out.
I didn’t have a 5.5mm socket, I found that 7/32″ worked perfectly.
Thanks!
Thanks a ton. This howto was very helpful in replacing my 1998 Buick Century’s blower motor resistor. It took a pretty strong jerk–actually two–to get the bad one out. And those back screws are hard to get to. I ended up taking out the whole blower motor, which is only held in by two screws. That gave me a lot better access to position the new resistor which slid neatly into place without any trouble. Just want to add, no one should be intimidated by taking out the blower motor. It came out and went back in easily. I can happily say I now have all the fan settings on my heater/ac again.