The Truth About Electrical Issues

In my experience, it’s possible to develop a love-hate relationship with almost any automotive system. Engines, transmissions, chassis and body — there are lots of ways to enjoy or detest any given job, with one exception: electrical. In my book, electrical system work is a hate-hate scenario. Issues can be intermittent, illogical and damn difficult to trace. The growing use of software to control simple systems like window lifts and door locks is a major factor, as is a serious lack of manufacturer understanding of how their products perform over 10-15 years of real-world use. We all see vehicles driving with dead locks, windows, driver information systems and others because owners can’t or won’t spend the big bucks necessary to troubleshoot these systems. What can we do?

There are ways to push back against the frustration of tough electrical issues. The first is to accept that computers are rarely the cause of electrical issues. They can be fried or damaged, but more often than not it’s because of the failure of a simple part like a sensor or actuator. Connectors are often overlooked when tracking down electrical system bugs. Technologies like GM’s “weather pack” gasketed connector have almost eliminated moisture-induced corrosion issues.

But there’s another issue: heat. Modern electrical systems use marginal wire gauges mainly because the switch gear is expected to carry control currents only, with computers driving relays to handle big power systems like sunroof motors or wipers. It’s surprising then, that overheating is still a major problem. Melted connectors and insulation, as well as heat-distorted switch contacts are still very common, but can be missed when we dive straight for the computer with every trouble code.

Around my office, my F-150 is legendary as the oldest beater in the parking lot and recently the wipers quit. The cause was a failure of the GEM module, which is inconveniently attached to the back of the fuse block. Why did it quit? It turns out there is a minor windshield leak that ran water behind the dash and over the unit. I can replace the module, but I had better address the leak if I want to avoid doing the knuckle-skinning job again.  On a customer car, this kind of advice is essential…fix the problem but also the root cause, even if it seems far removed from the problem.