Socket size to adjust headlights is it a E10 on a 99 blazer I know it's not the T10 am I right..

 

i think it is called a E10

 

Yeah, the reverse torx sockets are E-##. I'm not 100% sure if the E-10 is the correct one, but you are on the right track. I have also used a very small socket to adjust them. I think it was 4mm, 5mm, or 5.5mm.

 

I had to to stop at a weigh station on my drive home yesterday to aim mine lower on my 99 because it was so foggy that instead of going 60 mph, I had to 30. I've been using a (male) Torx driver that goes into the adjustment shaft. I always suspected there must be some sort of female version.