You should if requested by police, and were driving or riding a bike at the check point, or even walking if they think you were under the influence. Refusal would be 'contempt of cop' punishable by being charged with something in order to take you to jail. You do not have to submit to a blood alcohol test, and the police can not make you under most conditions, but you will automatically lose your license for a year if you refuse that, and the refusal is also likely to be 'contempt of cop'.
If you were arrested or charged with any crime, the proper questions are, can any evidence obtained in a test, search or confession be used against you, can you be convicted, and what can you do? If you don't know how to represent yourself effectively against an experienced prosecutor intending to convict, then hire an attorney that does, who will try to get a dismissal, diversion program, reduction, or other decent outcome through plea bargain, or take it to trial if appropriate.
If serious about hiring counsel to help in this, and if this is in SoCal courts, feel free to contact me.
