No headlights/bright light symbol on, on dash

[Landon730]

I have a 02 crew cab duramax that I'm completely stumped on. I drove it home one night and the headlights worked great. Went out the next morning and had no headlights. The bright light symbol is illuminated on the gauge cluster and hitting the dimmer switch makes no difference. I replaced the dimmer switch, same thing. Replaced the headlight switch, same thing. Replaced the dash ambient light sensor, same thing. Swapped relays, same thing. Just tried running a ground wire straight to the battery, same thing. Been working on it for four days and I'm completely stumped. Any ideas?

 

[Will L.]

Get a schematic. If you dont know how to follow it, post it here.
Throwing parts at electrical issue is the worst option. As you already see it gets expensive quick.

Imagine:
If the 2nd new part you put in was defective. The third part was the actual bad part. How will you ever know? If the wire harness has a bad connection, all the components are good and replacing them all wont fix it. It’s like your favorite number is 5 so you always pick horse number 5. You may win once in a while, but out of 12....?

some people use a lightbulb style test light, better is a multimeter. But best is a power probe 3,4, or the Hook. If you want all in one get the Hook. I prefer to test ohms with a multimeter, so I use the 3. There are videos that walk you through basic use and just playing with it will get 98% of people comfortable within a couple hours. Sounds like a pain, but being able to track electrical problems for the rest of hour life is well worth it. The only key rule is if the rig has airbags, learn that cars color wiring warnings for them and NEVER mess with airbags. The invention of the powerprobe turned thousands of guys that could only change batteries and starters onto chasing down and finding electrical problems instead of R&R parts guys.

 

[Landon730]

Get a schematic. If you dont know how to follow it, post it here.
Throwing parts at electrical issue is the worst option. As you already see it gets expensive quick.

Imagine:
If the 2nd new part you put in was defective. The third part was the actual bad part. How will you ever know? If the wire harness has a bad connection, all the components are good and replacing them all wont fix it. It’s like your favorite number is 5 so you always pick horse number 5. You may win once in a while, but out of 12....?

some people use a lightbulb style test light, better is a multimeter. But best is a power probe 3,4, or the Hook. If you want all in one get the Hook. I prefer to test ohms with a multimeter, so I use the 3. There are videos that walk you through basic use and just playing with it will get 98% of people comfortable within a couple hours. Sounds like a pain, but being able to track electrical problems for the rest of hour life is well worth it. The only key rule is if the rig has airbags, learn that cars color wiring warnings for them and NEVER mess with airbags. The invention of the powerprobe turned thousands of guys that could only change batteries and starters onto chasing down and finding electrical problems instead of R&R parts guys.

I've been ohming with a multimeter quite a bit. Only diagram I have is out of a chilton book and its subpar to say the least. I just don't really know what I'm looking for at this point. As far as what wire should read what. I know grounds should be .1 or so. Its a pain without a good diagram too dealing with electrical.

 

[btfarm]

Sounds to me like your turn/cruise/wiper stalk might be failing

 

[Landon730]

Sounds to me like your turn/cruise/wiper stalk might failing

Already replaced it with no change. No easy fixes here!

 

[Will L.]

Call a dealership and find out if factory manual is available. It will be electronic form.
Maybe AllData, or the like. It might cost a couple hundred, but how much have you wasted all ready in parts... What about the next time another electrical problem occurs....
Sometimes a harbor freight wrench is ok to remove a bolt. Sometimes you need a high quality one to get the job done. A specific manual is the most important tool for any rig.

 

[Landon730]

Call a dealership and find out if factory manual is available. It will be electronic form.
Maybe AllData, or the like. It might cost a couple hundred, but how much have you wasted all ready in parts... What about the next time another electrical problem occurs....
Sometimes a harbor freight wrench is ok to remove a bolt. Sometimes you need a high quality one to get the job done. A specific manual is the most important tool for any rig.

I’ll see what i can come up with. I have a 03 needing a cp3 and i’d rather have another running truck right now then buying a manual over some darn headlights. I’ll call the dealer tomorrow and see what they say though. I’ve got two different chevy dealers here.

 

[snarl95]

You checked the fuses?

 

[Landon730]

Call a dealership and find out if factory manual is available. It will be electronic form.
Maybe AllData, or the like. It might cost a couple hundred, but how much have you wasted all ready in parts... What about the next time another electrical problem occurs....
Sometimes a harbor freight wrench is ok to remove a bolt. Sometimes you need a high quality one to get the job done. A specific manual is the most important tool for any rig.

You checked the fuses?

UPDATE: fuse box itself is messed up. Ran power from the battery to the power pin for the relay and it works. Fuse box was receiving power but it wasn’t making it to the “power in” pin on the relay