it is known as the drl system (daytime running lights)
GMC Q&AAsk Your Question
1999 GMC Suburban 1500 Question: daytime lights (headlights) will not come on when vehicle is started. fuse is ok
Answer #1Greg's Orange Auto (13991 Answers) , Orange, CA - (714) 361-9386globalhelper August 01, 2012, 07:21Master
start with cking pwr at sockets
Answer #2ziptie12 August 01, 2012, 15:05Master
Check to see if yours are the type where it has to be in 'drive' for them to come on.I think I've seen some with a set-up like that.
Replypushrod, August 01, 2012, 20:08Master
Also with park brake off.
Replyziptie12, August 02, 2012, 18:53Master
OOPS , I forgot that part yes. thanks to wetry