Phone doesn t connect to Blueteeth

when i use the buttons on the wheel, the Bt works ok. most times it doesn t understand the name i am searching, so i usually have to get my phone out and say the number, not a big deal. my issue, if one wants to call it that, is, i am on the phone and bt is turned on on the phone, i get in my car, start it, but it won t switch over to hf, or if i dial my phone, it won t connect to bt, but it will if i say the name or number from scratch, am i doing something wrong or not doing something correctly ?

thanks Al