Car Electrical System Questions

By Cathy Reichow

Q. I own a 1995 Chevrolet Monte Carlo. At times my car will not start (won’t crank), but I have radio and headlights. It is a very intermittent problem. This is very frustrating. Yesterday, after I got a ride to work, my husband went out, and the car started. Do you have any ideas?

A. Believe it or not we have several customers with your exact concern. There are a few things you can do to help determine the problem. However, because the condition is intermittent, it could be difficult. Your vehicle is equipped with a VSS (vehicle security system) with a computer chip in the key. Sometimes, especially if you use the key often, it can wear out. Exchange keys with your husband and try his for a while. The other possibilities include a battery or starter problem. At a repair shop they can load test the battery and also check the starter for excessive amperage draw. The best thing that can happen is for the car to not start while it’s in the shop.

Q. I have a 1995 Mercury Grand Marquis and the interior fuse blows intermittently. Sometimes it will last up to a week, other times only a day. Any ideas?

A. Intermittent problems usually are the most frustrating and difficult for both the vehicle owner and technician. The first thing that my technician would do is a search for any TSB’s (Technical Service Bulletins.) This would advise him if the manufacturer had a consistent complaint and repair for this problem. The next step would be to find out exactly what other accessories are on that circuit and disconnect the controlled items one at a time. It may turn out to be something as simple as a doorjamb switch. Be patient; I’m sure your problem can be solved with a little time and technology.

Q. My car is four years old and when I took it in for service, they told me my battery was marginal. Since winter is over, should I wait until next winter to replace it?

A. Four years is the average life for a battery. Unless you enjoy being stranded, replacement of your battery is a good preventive maintenance item. A weak battery can affect your electrical and computer system. Hot summer weather can have the same effect or worse than winter weather on a car battery. Take the plunge . . . buy a new battery. When having the battery installed it's important that the battery cables are cleaned and then protected with anti-corrosive spray. Your technician will also go through a procedure to reprogram your computer system. Some cars require that this be done with a scan tool. Make sure someone qualified replaces it for you.

Q. My car has a driver's side air bag. Sometimes while driving down the road the air bag light flashes on and off. What does this mean?

A. Your air bag system is controlled by a computer and a series of sensors. In order for your safety restraint system to function properly, every component must be in working order. When the air bag light flashes on and off it can mean there is a malfunction in one or more system components. You need to take your vehicle into a shop that has the ability to access the system's trouble codes. When the system is not functioning properly it can prohibit the air bag from activating if needed.

Q. I have a 1995 Ford Escort, and I get a moisture build-up in my headlights. Is there anything I can do to prevent this?

A. Your car is equipped with what is called composite headlights. This means the headlight lens is a sealed unit, and the headlight bulb generally screws in the back part of the lens. When the headlight burns out only the bulb is replaced. Sometimes the weather seal goes bad, or the lens gets a small stone hole in it that allows moisture to accumulate. Sometimes the lens can be dried out with a hair dryer or heat gun (carefully -- not to melt the lens), then a small vent hole properly positioned can be installed to help keep the moisture from re-occurring. If this does not cure the problem the lens may need to be replaced.

Provided as a public service by Car Care Council.