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CHRIS ZAPANTIS
CHRIS ZAPANTIS,
Category: Buick
Satisfied Customers: 159
Experience:  AUTO TECH at G&M EXXON
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Buick Century: : I am having the same problem on a

Customer Question

Hello:
I am having the same problem on a 2004 Buick Century as this person described below. I replaced the multifunction switch in August 2015. The switch still feels crisp and new when switching between high and low beam.
Do you think problem is in the wire harness? All the fuses look OK. I can't find any relay for the headlights, none is indicated on the owner's manual fuse diagram.
This car also has an ambient light sensor which turns on the low beams if it is dark even if the headlight switch is in off position. Could the problem be this sensor?
"2003 buick century. no low beams. all other lights work properly. I have completed the following: replaced bulbs, replaced fuses, replaced headlight dimmer switch. none of those worked. using voltage meter, it appears that there is no voltage getting to the fuse box/fuses for headlights that is in the box under the hood. similarly, voltage meter indicates some, but not all, of the wires that plug into the dimmer switch are getting voltage to the switch. "
Submitted: 11 months ago.
Category: Buick
Expert:  CHRIS ZAPANTIS replied 11 months ago.
hi im chris and i will assist you
Expert:  CHRIS ZAPANTIS replied 11 months ago.
is your car equipped with a 3.1?
Customer: replied 11 months ago.
Yes, 3.1 liters
Expert:  CHRIS ZAPANTIS replied 11 months ago.
go to the headlight dimmer switch
Expert:  CHRIS ZAPANTIS replied 11 months ago.
ground the dark blue wire and tell me what happens
Customer: replied 11 months ago.
Look for the dark blue wire where? under the driver's side of the dash?
Expert:  CHRIS ZAPANTIS replied 11 months ago.
on the switch itself pull it out so its easy access
Customer: replied 11 months ago.
Do you mean the multifunction switch on the column? That switch is not easy to remove.Or do you the headlight pull-on off switch on the dash to the left of the steering column?
Expert:  CHRIS ZAPANTIS replied 11 months ago.
headlight
Customer: replied 11 months ago.
"headlight" means the pull -push headlight switch on the dash? Remember, bright/dim on this car part of the multifunction turn signal switch.
Expert:  CHRIS ZAPANTIS replied 11 months ago.
yes
Expert:  CHRIS ZAPANTIS replied 11 months ago.
i presume you checked fuses right?
Customer: replied 11 months ago.
OK. I can't get to the car right now.Assuming I ground the blue wire as indicated, what is the diagnosis if the low beam does or does not turn of?You want me to do this will rhe headlight switch is in the ON position, correct?
Expert:  CHRIS ZAPANTIS replied 11 months ago.
no key on switch off
Customer: replied 11 months ago.
OK, so I ground the blue wire with headlight switch off. What does it mean if the low beam headlights come on?
Customer: replied 11 months ago.
And what if the low beams do not turn on?
Expert:  CHRIS ZAPANTIS replied 11 months ago.
we have to test further
Expert:  CHRIS ZAPANTIS replied 11 months ago.
is there a yellow wire too?
Customer: replied 11 months ago.
Yellow wire? I'd have to look. The car is not here at present.Please tell me what it means if the low beams turn on when blue wire is grounded and the low beam turns on? That the headlight switch is bad?
Expert:  CHRIS ZAPANTIS replied 11 months ago.
im getting 2 different diagrams from 2 companies here
Expert:  CHRIS ZAPANTIS replied 11 months ago.
in one diafram it means dimmer is bad
Expert:  CHRIS ZAPANTIS replied 11 months ago.
i want to make sure which s right
Expert:  CHRIS ZAPANTIS replied 11 months ago.
you said you changed the dimmer right?
Expert:  CHRIS ZAPANTIS replied 11 months ago.
is there a yellow wire on your headlight switch?
Customer: replied 11 months ago.
OK, what does it mean in the other diagram?And does either diagram show a headlight relay module or an ambient light sensor? My owner's manual fuse diagram does not show any headlight relay. That puzzles me.I changed the multifunction switch on the steering column in August 2015. The dimmer switch action feel was bad. The switch action on the relacement dimmer switch still feels crisp and new.
Expert:  CHRIS ZAPANTIS replied 11 months ago.
it shows an auto headlight relay
Expert:  CHRIS ZAPANTIS replied 11 months ago.
no light sensor
Expert:  CHRIS ZAPANTIS replied 11 months ago.
on the other diagram a yellow wire goes to the dark blue at the dimmer
Expert:  CHRIS ZAPANTIS replied 11 months ago.
thats why i was asking you have a yellow there?
Customer: replied 11 months ago.
I don't have the car right now, so I can't say about the yellow wire. What is the function of the yellow wire?Do you mean that the yellow wire leads to a headlight relay?
Expert:  CHRIS ZAPANTIS replied 11 months ago.
looks to me like you need a dimmer switch
Expert:  CHRIS ZAPANTIS replied 11 months ago.
im 90 percent sure
Expert:  CHRIS ZAPANTIS replied 11 months ago.
if you dont have the car i cant possibly diagnose
Customer: replied 11 months ago.
Chris, can you verify that there is no headlight relay on a 2004 Buick Century?Also, how to test the push-pull headlight on/off switch?
Expert:  CHRIS ZAPANTIS replied 11 months ago.
there is a relay the auto headlight relay
Customer: replied 11 months ago.
Where is the relay located? In the under the hood fuse box or under the dash?I
Expert:  CHRIS ZAPANTIS replied 11 months ago.
onderhood box gimme a min ill give you exact instructions for test
Expert:  CHRIS ZAPANTIS replied 11 months ago.
ground pin a2 at headlight dimmer switch to see if light come onif they dont check wires back to headlights for an openif they do come on ground pin a3 on headlight dimmer switch and see if both high and low work normallyif they dont replace dimmer switchif they do check yellow wire from a3 to headlight switch for an open, also check black/white wire for ground. run through this and you will diagnose it by yourself!
Expert:  CHRIS ZAPANTIS replied 11 months ago.
a2 on dimmer is dark bluea3 on dimmer is yellow
Customer: replied 11 months ago.
OK, I'll follow your instructions.One other question: I cannot find the ambient light sensor. I assume it is mounted in front hear the grille.This sensor is not my imagination. It has aGM part number. Where should I look?
Expert:  CHRIS ZAPANTIS replied 11 months ago.
it would be right on your dash
Expert:  CHRIS ZAPANTIS replied 11 months ago.
your car doesnt have it
Expert:  CHRIS ZAPANTIS replied 11 months ago.
on top of dash by window
Customer: replied 11 months ago.
You mean on the surface of the dash inside?Doesn't have it. When not malfunctioning, this car will turn low beams on if it is dark outside, even if the push pull headlight switch is in the off Position.
Expert:  CHRIS ZAPANTIS replied 11 months ago.
only thing behind grille is ambient temp sensor
Expert:  CHRIS ZAPANTIS replied 11 months ago.
yes right on surface
Customer: replied 11 months ago.
Chris, do the wiring diagrams indicate wire(s) to/from this sensor?
Expert:  CHRIS ZAPANTIS replied 11 months ago.
no but it doesnt have to it does indicate wires from bcm. that thing may go to bcm then output from there
Expert:  CHRIS ZAPANTIS replied 11 months ago.
for diagnosing lights not coming on manually it wont make a difference
Customer: replied 11 months ago.
BCM -- body control module? Is it possible that the BCM module functions include headlight relay(s)?
Expert:  CHRIS ZAPANTIS replied 11 months ago.
yes it is but dont run ahead
Customer: replied 11 months ago.
Don't run ahead? What do you mean?
Expert:  CHRIS ZAPANTIS replied 11 months ago.
even with bcm out theres a physical manual link through the switch
Expert:  CHRIS ZAPANTIS replied 11 months ago.
dont overthink
Expert:  CHRIS ZAPANTIS replied 11 months ago.
bcm wires are coming in in parallel they are nit in series
Expert:  CHRIS ZAPANTIS replied 11 months ago.
do the test and thank me later lol
Customer: replied 11 months ago.
Chris, that is probably enough for now. I'll try the test you suggested.One othr possibility -- could the wires in the headlight wire harness have a broken wire? How to test for that?
Expert:  CHRIS ZAPANTIS replied 11 months ago.
if you read after the first test you will know if they are good
Customer: replied 11 months ago.
Chris, thank you. Enough for now.Bye
Expert:  CHRIS ZAPANTIS replied 11 months ago.
thanks and please rate me so i get credit
Customer: replied 11 months ago.
OK
Expert:  CHRIS ZAPANTIS replied 11 months ago.
ill leave it open so you can get back to me
Customer: replied 11 months ago.
All right, please leave it open. I can't can't test the car right now.
Expert:  CHRIS ZAPANTIS replied 11 months ago.
you wont have to pay again for someone
Expert:  CHRIS ZAPANTIS replied 11 months ago.
just know weekdays the best time to get to me is after 6 cause i work