Never married, separated, one child age 4. Mother withholds child visitation at will. Falsely accuses father of abuse. What do I do?

If you are not going in to protect your rights as a parent because you are afraid the court might "believe her lies," all you are doing is eliminating any chance that the court will believe you. Go to court, hire a lawyer if you can afford one (if not, Google "low income family law firms" or something like that to see what you can find. Or, go to the Family Law self-help center in your local Superior Court (almost all counties have such a program), and they will help you fill out the forms and get in front of a judge). Doing nothing because you are afraid just gives the other parent what they want without having to do anything to get it; so get in front of a judge and tell them what's going on. You will have a relationship with your child, and it just might be 50/50. Because mom has kept you from your child for so long, you may need to do a step-up in time, and possibly with a monitor for the first few visits (it's not so bad and would actually help you here), but you will get the time with your child. Do something NOW, do not wait any longer. 70% to 80% of the people getting divorced in California do it without lawyers; so can you. Good luck!