2003 trailblazer ext having to replace headlights almost every 3 to 5 months
normal ???

Welcome to AF. PITA, I have the same issue with my 2002. The Sylvania Brite Blues burned out every 7 months. Even melted the connectors. I Went back to std bulks, soldered in HD connectors from NAPA, still some issues, took the covers off the back of the lamps to allow more cooling. Check your grounds also, this can ciuse high voltage, also check inside the lamp connectors for signs over overheating.

thanks,for the reply will try the same thing

Check your running voltage. Your voltage regulator may be over charging.

Im still on my original lights from back in 2001

2003 trailblazer ext having to replace headlights almost every 3 to 5 months
normal ???

I have a 2004 TB and am having the same issue. I have also noticed that my volt meter drops to about 8 volts after letting off the gas during cold weather. After some research I have heard that the TB's have a secondary smog pump that is supposed to work only during startup but can and does kick in after startup during cold weather. This is a huge strain on the alternator and electrical system. I am wondering if this draw is causing premature failure of the lights and who knows what else.

Welcome to AF, you have tagged onto an old thread, please start a new one, thanks.