1991 BMW M3 Electrical System Diagnosis Cost

The electrical system of a vehicle encompasses numerous components of multiple systems which function together or separately. These systems can range from engine or transmission control systems to entertainment systems. Since many systems are interdependent, the failure of one system which is seemingly unrelated to another may share common faults. That being the case, the electrical system of the vehicle must be properly maintained, protected, and kept in good repair. When faults do arise in the electrical system, a thorough inspection of the electrical systems affected by the fault will likely be required.

The electrical system begins at the battery for every vehicle. The battery sends electrical power to the entire vehicle either using one of many control modules or directly. These control modules or independent components communicate using mainly electrical signals, and these are transmitted over a wired network within the vehicle. This allows most control units in the electrical system to understand what is happening elsewhere in the vehicle, and use that data to control separate functions. This creates an interdependent electrical system which is complicated, but gives many clues to a technician upon an inspection or test.

Due to the nature of electrical systems on modern vehicles, the range of problems these can cause are nearly limitless. However, there is a way to categorize them in two ways. Permanent and intermittent problems. Permanent problems appear and remain. This may be the vehicle will not start, the radio does not work, or the door chime will not turn off among many, many others. These problems are more straight-forward to diagnose since they present themselves at all time. This means there will always be a fault to find. Intermittent electrical problems, however, can be difficult or impossible to locate, since they appear then disappear without warning. The best case scenario for an intermittent issue is when replicating the problem is easily accomplished and understood. This allows a technician to make an issue semi-permanent, allowing them to find the fault. Other issues that come and go without warning and cannot be replicated on demand must occur when the technician is servicing the vehicle, otherwise there is no problem to correct. It is most important to understand that electrical system faults always require inspection, and can include the vehicle working in any manner, or not working at all.