99 yukon taillight issue

[joyride]

Can't figure out what's going on with my mom's Yukon. Apparently the driver side taillight isn't exactly working right. If I manually turn on the lights from the switch in the dash, the taillights will light up. Anything else, nope. The passenger side works fine, but the turn signals, hazards, and I think brake light doesn't work in the driver side tail light. I replaced the bulbs, went to the junkyard to get a new piece that the bulbs push into, that's bolted to the taillight itself (I don't know the name of that piece) and neither of those 2 seemed to do the trick. I went through the fuses in the dash, put some others in just for peace of mind, looked at the relays under the hood, looked at the ground under the back bumper and nothing. I didn't clean up the ground(s) underneath the back bumper and reattached them but I guess I could if need be. Does anyone else have any other ideas? Thanks for any and all help!

 

[Y2KpewterZ]

The circuit board thing that bolts to the back of the housing could be bad since it is a junk yard piece. Its a common problem. Autozone sells them brand new.

 

[SunlitComet]

activate and deactivate the hazard switch is one idea in case the terminals in the switch are not setting properly killing off turn and brake signals as well as a possible second broken light board.

 

[joyride]

Thanks guys I'll go ahead and do that today after work. Appreciate the help!!

 

[TigerEyz3]

Could also be the multi-function switch (wiper control, turn signal, cruise control, hazard lights) needs to be replaced. I had a similar problem with my truck and all was fixed after replacing that part.