Have a 2004 Hyundai xg350L. My trunk lights have not worked in while. Replaced bulbs in trunk and also same bulb in glove box. All three bulbs do not work after replacement. The rest of courtesy lights work. I tested trunk switch and it tests good. I have some sort of ground problem in the courtesy light circuit which is hot ground.

My thoughts are that glove box light not working along with trunk lights which come off of same circuit is related. I do get power to trunks lights but when shut car off trunk open light in instrument cluster stays on very dimmly when trunk switch is in position for trunk closed. ALso when light is on in trunk it is dim. What is purpose for trunk lid relay. Need help tracing backwards to find source of Ground leak. Battery dies from the ground leak.

I have also had recent problem at same time of speed sensor issue or possible low voltage causing transmission to safe to 3rd gear if this somehow could be related. CUrrently transmission shifting fine, though.

 

I would suspect a voltage leak from a bad switch. Dangerous since one day it could catch fire on you.