Ask Joe Mechanic - Common Electrical Problems

As vehicles become increasingly more complicated, making simple electrical repairs has

Example of a vehicle's fuse box.

almost become a thing of the past. It used to be that people changed their own alternators and starters, now it is almost a task to even find them. And, with all the interconnecting computers in a vehicle, an innocent mistake can end up costing hundreds, even thousands of dollars to repair.  

I recommend that anyone who does not have some mechanical ability does not touch electrical repairs.  As, some of the worst situations I have seen created, were done by people who thought they knew what they were doing.

If you choose to do so, simple things like light bulb replacement generally is not too complicated, most owners’ manuals will tell you how to change taillight bulbs, etc. Headlight designs are becoming increasingly complicated with High-intensity Zenon bulbs and such. One caution whenever changing a halogen headlight or fog light bulb is to not touch the glass part of the bulb as the oils from your skin can cause premature bulb failure.

Another common repair, which is quite simple, is replacing a blown fuse. If something is not working on your car, find the location of your fuse box in your owner’s manual. There will be a diagram, usually on the fuse box cover, which identifies what fuse controls what function. If you pull out that fuse and it looks like it has a break in the filament or looks burned, it is blown out. Replace it with the identical amp fuse, they are often color-coded and are marked 10, 15, 20 etc. If a fuse blows out a second time, it means you have a more serious problem in that circuit and you need to get it checked by a professional technician. NEVER wrap a fuse with tin foil, stick a coin in the fuse’s place or put a jumper wire in the fuse box! I saw a person wrap a fuse with tin foil and he melted the entire wiring harness from front of the car to the back. With todays’ systems, you can easily fry an expensive computer or even worse, set fire to your vehicle.

On older cars, it is still easy to change a starter or alternator, but one caution if you plan to do this yourself, always disconnect the battery first to prevent arcing and fire.

Other than these few items, I recommend leaving electrical repairs to the professionals as it can prove to be less costly.