A traffic stop for illegal tint, cop searches immediate area finds nothing, then asks for and obtains written consent for a thorough search and brings the K-9 which alerts to drugs. Good or bad search?

What does "searches immediate area" entail?

the wingspan of the defendant

Why did he do the initial search with a window tint violation? See Arizona v. Gant No. 07-542
When did he issue the ticket? If ticket was issued and he further detained him I think you have some serious issues unless you have probable cause for the detention.
How long did they wait?