When you are experiencing car trouble, diagnosing the problem can often be harder and more time-consuming then fixing the problem once you find it. Dealerships and auto repair shops can charge outrageous fees to hook your vehicle to a diagnostic machine and still not find the problem. But there are ways to diagnose your problem for free.
Many auto parts stores offer free automotive help. Advance Auto Parts offers free diagnostics with the same machine auto repair shops charge for. Not to mention they will actually do the little jobs for you. If you have a dying battery and go to Advance for a replacement, they will change the battery for you free if you do not know how. The same goes for other small jobs such as headlight bulbs and fuses (see Reference 1).
Auto Zone is another store that offers free services. They will test batteries and alternators to see if they are causing the problem and will also use a diagnostic machine to establish what other problems may exist, according to the company website.
Often you can ascertain what is ailing your vehicle without ever leaving the house. Many websites allow you to ask auto repair questions online free. Websites such as 2carpros have forums where you can post your car questions and get answers from mechanics and car enthusiasts quickly. Just about any vehicle and any problem can be found on this forum and often a search will reveal your question already asked and answered (see Reference 2).
Beware of sites that promise free diagnostics but don't follow through. One such site allows you to submit your auto question for what it claims is free but then redirects you to a site where experts answer questions in exchange for small fees. The fees are usually considerably less expensive than taking your vehicle to a mechanic but are still not the free answers promised.
Check out your local library for vehicle-specific auto repair manuals such as the ones published by Haynes. These contain a troubleshooting section that details what could be wrong and how to test it for a wide variety of problems. Once you determine the problem, other sections of the book will give you step-by-step instructions that will help you repair the problem yourself. Other books such as Auto Repair for Dummies can provide more generalized help.