High Beams won't work but low beams work - Exterior Forum

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High Beams won't work but low beams work
Thursday, January 17, 2008 6:02 PM
This has been happening for awhile now on my 2003 cavi, and I'm really getting sick of it. when I click high beams on, no headlights come on at all, but all parking and turn signals work. This all happened when the driver side went out, and I was driving around with only the passenger side high beam working. I replaced the driver side bulb, it worked for about a day, then died. then I drove around for about a week or so, and then the passenger side went out. then I started to do some troubleshooting.


-The high beam indicator functions properly.

-The DRL's work fine and light up normal, and yet they take wattage from the high beams that don't work.

-Both headlights have been replaced and only low beams work, and I bought three brand new sets to make sure it wasn't the bulbs.

-I replaced the headlight switch, everything still worked the same, except the high beams.

-Checked fuses about 3 times just in case I was a retard the first two times and missed something, but there still fine.

-Wiring to headlight harness appears to be fine, although I haven't really followed the wire past the two relays by the front bumper.

I give up. You win Cavi.

Any insight would be appreciated as I have searched and haven't really came up with a remedy. Thanks in advance.

Re: High Beams won't work but low beams work
Thursday, January 17, 2008 7:02 PM
Check the ground under the battery tray for corrosion or being loose. Corrosion especially if you had a leaky battery before.
the headlights should have 12v all the time with the key on, both high and low beam, the ground is what is switched through the switch inside. The ground comes from under the battery.


01 cav w/01 3400 gam gt 4t45e

Re: High Beams won't work but low beams work
Thursday, January 17, 2008 11:52 PM
or check your DRLs maybe ?




Re: High Beams won't work but low beams work
Friday, January 18, 2008 11:19 AM
Checked the under the battery, but higly unlikely the optima yellow top would leak... no signs of corrosion or ground being loose.

DRLS work like a charm unfortunately.


Any other ideas anyone? I've literally exhausted every option I could think of and still no results.

O and by the way, usually when a light goes out, the Service light comes on. My Service light is NOT on....... Kinda Weird.
Re: High Beams won't work but low beams work
Friday, January 18, 2008 12:43 PM
update:

just checked everything again.... still can't figure out why the high beams aren't working. tested each wire going into the harness while the low beams we're on, 2 of the three wires were getting voltage, one wasn't, I presume that's normal. Then when the high beams were on, tested again, and all three wires going into the harness were getting power on both sides. Then I tested the headlight harness/socket itself, when the high beam was on, only one prong was getting power.... interesting... Is that normal? I may be replacing the harness/socket itself and try that.
Re: High Beams won't work but low beams work
Friday, January 18, 2008 4:30 PM
my sunfire just started doing the opposite. i have high beams but no low beams. at least my high beams aren't any brighter then the low beams.



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Re: High Beams won't work but low beams work
Friday, January 18, 2008 5:15 PM
Ok so you are obviously getting ether no + or - when you turn your high beams on .... Check.
Now u have to work your way back from that ...
I would now go to the power source that goes into the relays and make sure that you get signal from the wire that gets power
from the switch ......
There is going to be a constant 12 volt + going into the relay with 2 more + wires that are your high and low beam.
i bet that if u check the signal coming from the switch for both high and low will be giving power when they are on ...
if so the relay is probbaly dirty.
if im wrong on this im sorry ...... but anything can be better then no input.
i would look @ the relay ..... if the connection pads are black(inside the relay) try using sandpaper to clean those up to make a better conenction .....


On another completely different note ....lol

This maybe a stupid question but ..... are you sure ur suppose to have signal from all 3 wires when your high beams are on ....???

One is for your ground one is for high and one is for low .....
a test for this is to first figure out which one is which and mark which side is which on the plastic housing around the prongs
hook up the high beam + and - prongs and turn them on ..... if you have signal you, kno that when you turn your high beams on your getting 2 feeds when you should be getting one ......

if you find out there is not suppose to be 3 signals coming into the bulb for your high beams to be on and the end result is your high's are off

try and trace this back again to behind the relay to the power from the switches for your high and low's into the relay. That will tell you if its the relay again.
IF THIS IS THE CASE
u need to trace it back to the next hump which would be ether the switch or the computer ... whichever comes first ...
you may be able to get a wiring diagram on this fourm somewhere for your spacific vehical ....
also ... im going on the knowledge of my car ..... so im sorry if this is a waste of time


i hope this helps .....or @ least can give u an idea of what to look @






Re: High Beams won't work but low beams work
Friday, January 18, 2008 5:25 PM
Same problem here... still can't figure it out



Re: High Beams won't work but low beams work
Friday, January 18, 2008 5:28 PM
did you trace all the way back to the actuall switch?
and did you wire the bulb with only a single + going to the high beam connection on the bulb ?
instead of 2 feed's from the socet when your high's are on ..




Re: High Beams won't work but low beams work
Friday, January 18, 2008 8:22 PM
Do you have factory fog lights?


01 cav w/01 3400 gam gt 4t45e

Re: High Beams won't work but low beams work
Saturday, January 19, 2008 7:16 AM
I do have factory foglights, but one is out right now (bulb blew out). I checked the foglight relay and everything seems to be ok. As far as for what Doyle said, I will be trying that tomorrow when I have time, unfortunately I was unable to look at anything past where the headlight wiring goes underneath the battery tray.... There is always the posssibility that the wiring from there to the headlight switch could be bad, but before I do anything I'm going to switch out the headlight harnesses and try that first. I'll try to keep everyone updated because I'm sure I'm not the first and won't be the last with this problem.

Re: High Beams won't work but low beams work
Saturday, January 19, 2008 9:27 AM
its probably your stiwtch box, mine did the same thing 2 years ago, you can pick one up from the wreckers for like $40 or try and fix it if you dont have cruise it'll be a little less.





Re: High Beams won't work but low beams work
Saturday, January 19, 2008 12:44 PM
where is this switch box you speak of? I do have cruise control.
Re: High Beams won't work but low beams work
Sunday, January 20, 2008 9:13 AM
He has to be talking about the whole switch mechanism on the column. That has everything switch related in it for the highs, lows and parking. He wanted to know itf you had cruise because thats wired into the switch also.
I would get a wiring diagram and check for the correct powers and grounds before you change it. I have been looking for a diagram but I cant seem to find the circuit with the headlights, I found the switch with parking and turn signals but no head lights. Im going to work in a little bit, Ill look there and get back to you.


01 cav w/01 3400 gam gt 4t45e

Re: High Beams won't work but low beams work
Sunday, January 20, 2008 9:41 AM
here you go, good luck.



01 cav w/01 3400 gam gt 4t45e

Re: High Beams won't work but low beams work
Sunday, January 20, 2008 9:56 AM
Not too clear, sorry, Ill shoot a copy over in your email. Scanned docs, dont come out too clear.


01 cav w/01 3400 gam gt 4t45e

Re: High Beams won't work but low beams work
Sunday, January 20, 2008 5:17 PM
Thanks guys, The wiring diagram should help out. When I figure out what's wrong with the high beams, I will post the solution so others can search.
Re: High Beams won't work but low beams work
Wednesday, January 23, 2008 5:03 PM
Any luck?


01 cav w/01 3400 gam gt 4t45e

Re: High Beams won't work but low beams work
Sunday, January 27, 2008 10:00 AM
None whatsoever. The only thing that I'm wondering is if the two relays by the bumpers have anything to do with high beams not working? I know one of them controls the foglights so I imagine the other one controls the headlights. I think i'm bout to suck it up for once and take it to the dealership.....
Re: High Beams won't work but low beams work
Thursday, January 31, 2008 4:22 PM
prolly just a shot in the dark but try changing your turn signal switch



Re: High Beams won't work but low beams work
Thursday, January 31, 2008 4:49 PM
Sounds like the switch itself (yes the switch located on the column). My 97 had the same trouble once (high beams worked but the low beams wouldnt), and it turned out to be a bad switch.






Re: High Beams won't work but low beams work
Thursday, January 31, 2008 9:26 PM
Fog lamp relay has nothing to do with the headlights.
The DRL will not prevent the headlamps to turn on.

Column switch test:
1....Unplug either one of your headlights , take a grounded wire and touch it on pin c of the actual light bulb plug, it should be pink(or orange), this will bypass the column switch for the high beams.

2....Since you said that the lows work, this may make no diff but is any one else wants to check their lows, your going to want to do the same thing but attach the grounded wire to pin A blue wire, which bypasses the column switch for the low beams.

Both front bulbs run from the same wires, there fore when you alpply a ground to one bulb socket , the other side bulb will light.

If both tests will make the bulbs turn on, you need to move into the car to test the switch inputs.
1...Remove the lower half of the steering column, 3 screws.Then pop the top off also.

2...On the switch look for a black and a black/ white wire. those should be grounds all of the time. they will be on pins E and A

3...At this point you can test the outputs of the switch. remember the pink(or orange) and blue wires from up front. Well they are right there, on pins C and B. when you turn on the low beams the blue wire turns to ground, and when th highs are turned on the pink wire goes to ground. this can be checked by attaching a test light or volt meter to the positive post of the battery and then probing the pink and blue wires while turning the high and lows on.

Dont take it to a dealer, Its a simple switched electical circuit, like a light switch at home.
The BCM does not operate the High beams at all, It monitors them but thats it , so it can turn the little blue indicator light on in the cluster.



01 cav w/01 3400 gam gt 4t45e

Re: High Beams won't work but low beams work
Thursday, January 31, 2008 9:31 PM
Make sure you look at the pin Letters on the front bulbs, the left on has 2 blues. Dont mess with pin B when grounding or you will pop the left headlight fuse. Just remember dont touch the jumper to pin B on either light.


01 cav w/01 3400 gam gt 4t45e

Re: High Beams won't work but low beams work
Sunday, February 03, 2008 2:43 PM
I am having the same problem in my 99 cav...
New DRL Relay, and I tried switching the Multifuction switch with one I know is good and it is still doing it
anyone know th cause?



ShowFire

Re: High Beams won't work but low beams work
Sunday, February 03, 2008 5:23 PM
I replaced the switch a few months ago. The whole reason I replaced it is because my headlights stopped turning on period, and it wouldn't click anymore. Replaced the switch, normal headlights come on, and when I click for brights, the fogs shut off, high beam indicator turns on, but no highs.



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