1 the tail light gave him that reason to pull you over..

Now when he asked you to search the car..
You could of said no.. if he really wanted to be an ass about it,he could of held you there and get a warrent etc etc.. But a judge just dont give out search warrents that easy.

Now if he say a bag of weed or a blunt laying in view,or anything illegal in view.. then he can then have "probibal cause" (sp) to search..

Now if he did search,without asking.. and found like a bag of weed,he can arrest you,book you.. but then a good lawyer or judge can see it was an illegal search and suizure,and just have the case thrown out.But a dam arrest will still show..