All modules and electronics are tested and in working condition. Most modules and electronics need to be programed (coded) to your vehicle. We recommend finding a reputable and knowledgeable mechanic able to perform the programming before purchasing any module. Dealerships generally cannot program used modules since they only have the protocol to code new modules. We do not recommend using a dealership unless they can guarantee they can program a used module. Modules and electronics are not "defective" if you are unable to program into your vehicle. Since all modules are tested and working, if the module needs to be returned because you cannot program or communicate with it, the return will incur a 20% restocking fee. NO EXCEPTIONS.