Both Headlights stopped working but Brights work perfect

[probablecase]

1999 Suburban 2500 series: Both my headlights just stopped working except for the brights. I believe in coincidences but this is over the top. Any suggestions?

[fvargas]

I am having the same problem as you. I cannot help you but we can share in our woes. I have a 1999 K1500 4x4 burb. The highbeams and DRLs work well but not the low beams. I suspect a relay but do not know where to begin to look. I hope that it is not the multifunction switch that's on the steering column as it is one pricey item. Anyone out there with some first hand knowledge with this seemingly common problem please help. Thanks in advance.

[MT-2500]

Originally Posted by probablecase

1999 Suburban 2500 series: Both my headlights just stopped working except for the brights. I believe in coincidences but this is over the top. Any suggestions?

First thing make sure the bulbs are good. Any power on the low side?
The bulbs will sometimes burn out at same time or within 15-30 minutes of each other. Just like they have a timmer on them. If no power on low beam post back.
MT

[probablecase]

Originally Posted by fvargas

I am having the same problem as you. I cannot help you but we can share in our woes. I have a 1999 K1500 4x4 burb. The highbeams and DRLs work well but not the low beams. I suspect a relay but do not know where to begin to look. I hope that it is not the multifunction switch that's on the steering column as it is one pricey item. Anyone out there with some first hand knowledge with this seemingly common problem please help. Thanks in advance.

I was told that it is going to be the multifunction switch (which is the whole arm and control unit) and is about 160.00 from a local auto store. Ouch!

[MT-2500]

Originally Posted by probablecase

I was told that it is going to be the multifunction switch (which is the whole arm and control unit) and is about 160.00 from a local auto store. Ouch!

People will tell you anything.
That is why I said check for power to headlights.
If no power there the next step is.
Are you sure the dimmer switch is in the mutifunction switch?
Some are seperate.
The suburban has 2 or more types of headlights.
Get a wiring diagram and service manual and test light and check it out first.
If no book here is a link to all data online and in 10 minutes plus 24.95$ us plastic you can have all repair info and wiring diagrams on it.
MT

http://www.alldata.com/products/diy/index.html

[777stickman]

If you have an "old" body style '99 with quad headlights the, the low beams go thru the DRL relay. It is located in the convenience center (inside firewall behind parking brake pedal) in the bottom center position.

[fvargas]

If you have an "old" body style '99 with quad headlights the, the low beams go thru the DRL relay.

That is the kind of vehicle I have. I changed the DRL relay and that did not work. I was looking at the schematic and the two other possible problems are the body module and the multifunction switch (wipers, cruise control, hihg/low beams, and left/right turn signals).

Here is a monkey wrench to throw into the mix. I activated the cruise control and after I stepped on the brakes to deactivate it, the car shut off and the all gauges went all over the place. After a few minutes, the car started and everything was fine. This leads me to believe that either the multifunction switch is bad and/or I have a bigger problem with the car's pc board. any ideas.

Also, I am wanting to add the trailer hookup for trailer lights. would it be okay to just pigtail from the lights going to the rear. I know how to do this but wonder if I am going to overload something somewhere down the line, like the flasher relay for example. Thanks for your help.

[777stickman]

OK. Do what MT suggested and check for power at each headlight. Should be three or four wires in each plugin. One or two will be Black=Ground, LT Green=High beams and Tan=Lows. If you don't have power there, you need to work your way back until you find it and go from there.

As for the "monkey wrench" ??? Could be the multifuntion switch?? Lots of guys have replaced them. Some have found wiring problems going into or coming out of the switch also.

Good luck and keep us up to date as we like to learn too.............Steve

PS: I forgot to ask if you actually have DRL's and do they work?? If you do and they work that means the low beam bulbs are good!!

[fvargas]

I do have DRL and they work, so the bulbs are okay. I'll tackle the multifunction switch next and let you know what happens. Thanks

[MT-2500]

Get a test light and see if the dimmer switch on low beam low beam is switching 12 volts to the daylight running relay.
MT

http://members.troublecodes.net/crunch/99sub.pdf

[biggbabysweetz1]

i do appoligize first off for posting this so late into the game but anyhoo. ive had the same problem multiple times. 99.9% of the time the connector to the headlight came loose but this doesent appear to be your problem. follow the directions in previous posts for checking voltage. i really dont think your switch went bad, it should (most of the time) give you some warning signs, ie. flickering lights, electrical crackling sounds, etc. for your other question there shouldnt be any problem piggybacking your tail lights into a trailer harness. just make sure when its all said and done your trailer isnt drawing too much juice otherwise it can dim lights on that circuit, AND/OR blow fuses.
typically when you piggyback you wanna replace the tail light fuse with one thats 5 amps higher than the original, just to give your lights a little more breathing room.

[RailHog]

Hi, new to the forum and was looking for answers to another problem same make and model and saw this and thought I might help a little. I too have the same problem with my headlights. No low beams but the daytime running lights work, high beams work but no low beams with the switch in headlight mode.
Found that moving the tilt up or down would cause the headlights to come back on in normal mode. I suspect a cross/loose/broken wire but have'nt taken the time to rip it apart to find the broken/loose/ mashed wires. I am hoping it isn't a ribbon cable like the clock spring for the cruise controls in the 96 dodge grand caravan I had. I hope this is some help to you.
Mike

[RailHog]

In reply to the other question on trailer lights
"Also, I am wanting to add the trailer hookup for trailer lights. would it be okay to just pigtail from the lights going to the rear. I know how to do this but wonder if I am going to overload something somewhere down the line, like the flasher relay for example. "
There is a wiring harness already installed uder the bumper for it and a heavier gauge wire for battery for a camper. You have to connect them up in front for the trailer brakes and the big power wire but it's not that hard. You might want to change the flasher relay for a hevier duty one if the lights flash too fast. Good thing the factory expected us to tow with these huh?LOL

[richlandchev64]

it sounds like its the dimmer switch thats bad. the switch itself isnt acually in the blinker arm, there is a metal rod that goes from the blinker arm by the steering wheel down the steering column to the headlight dimmer switch which is mounted on the column down under the dash.