Top 20 1999 Buick Century Questions & Answers

check rear itself--u-joints --proper install of struts /bearings

Near the oil filter .

there is a light sensor locate up in defrost area of dash cover that controls the on and off of head lights

Your high beam switch is bad most likely.

Both radiator fan relay's ????? There are three relay's ! DTC P0481Cooling Fan Relay 2 Control Circuit Circuit Description Output Driver Modules (ODMs) are used by the PCM to turn on many of the current-driven devices that are needed to control various engine and Transaxle functions. Each ODM is capable of controlling up to 7 separate outputs by applying ground to the device which the PCM is commanding on. DTC P0481set indicates an improper voltage level has been detected, which controls the Cool Fan 2 and Cool Fan 3 Relays. Check cooling fan maxifuse 15 amp. This fuse supply's B+ voltage too cool fan relay's 2 & 3 control side . The PCM supply's a ground to energize these two relay's , the PCM is not seeing the correct voltage that it should be . The fuse could be the problem , an open circuit , the transistor or driver as GM calls it output driver module . The number 1 relay is working fine , with A/C on # 1 relay is turned on or energized by the PCM for low speed operation . There is a good video on youtube on how this three relay cooling fan system works an how to trouble shoot . Relay Driven Dual Cooling Fan Diagnostics

check for a vacuum leak.

e:$32.75 new switch https://www.am-autoparts.com/Buick/Century/turn-signal-switches-and-levers/AM-13244281/321502.html?utm_source=bing&utm_medium=cpc&utm_campaign=Shopping%20Campaign%20-%20Main%20-%20Medium%20Priority&utm_term=1100000069466&utm_content=all%20published%20products plus there is always used at auto salvage yard

You checked both large ignition 1 and ignition 2 fuses?

Sounds like engine may be partially seized, try turning engine by hand to see if it is too tight

Check the electrical circuit Starter Voltage Drop

With engine running what is voltage reading at the battery ?
Also a bad diode trio in the alternator will cause this problem if everything thing is charging ok

Is the coolant full ? Any discoloring of the coolant ,look like muddy water ? gm dexcool antifreeze if mixed with regular green coolant can gum up the works , clog heater cores , radiators etc.... Have you ever had the thermostat changed , cooling system flushed ?

the inlet valve will be in line with the inlet port the exhaust will be on line with an exhaust port

From what you said I would think you have a bad/loose connection. I have never had to change the fan resistor but from what I under stand usually when the resistor is bad the fan only run with the fan speed on the highest setting. If the fan quits working try putting the fan on the highest speed setting, see if fan starts working. Sorry but that all I got for now.

replace the light switch

Most likely a bad wheel bearing, or wiring to the wheel bearing. I would start by having it scanned to point you in the right direction. (What bearing to look at). Could also be something in the ABS module.

someone told me to by getting out of the car and locking the driver door with the key, going to the front passenger door and unlocking, then relocking the door using the key. I have to repeat this step 2-4 times and eventually it will start. ????????? This has nothing to do with it starting ! This is what's happening , Inside the lock cylinder are contacts that read the resistance of the pellet on the key , the contacts are getting worn out . You have two options , replace the lock cylinder or by-pass it all together . The PASS-Key II® ignition key (1) contains a unique resistor pellet which is idenified by the Body Control Module (BCM) (2). There are 15 different key (resistor) codes. Only one ignition key resistor pellet code will work with each PASS-Key II® theft deterrent system. Ignition Key Lock Cylinder The ignition lock cylinder contains spring loaded contacts which make physical contact with the ignition key when it is inserted into the ignition lock cylinder. This allows the ignition lock cylinder to provide the Body Control Module (BCM) (2) with the resistor code embedded in the ignition key. GM VATS Key Resistor Key Security Bypass http://www.autopartswarehouse.com/sku/Buick/Century/Standard/Ignition_Lock_Cylinder/1999/SIUS222L.html?apwcid=bngpla

Heater blower motor is the proper terminology for this. Best getting it with the fan attached. Said unit is under the hood attached with small bolts to the heater core box on the passenger side firewall. It's the round piece that sticks out and is easily replaced once you have everything out of your way.

had this problem on a Chrysler and it turned out to be the ballast resistor

Is there raw fuel coming out of the hose or regulator . These regulators have a diaphram inside that rots and leaks , Causes rich condition . Can cause misfire codes , rough running .