Car Automotive

Posts Tagged ‘vehicle’

The elaborate system of ducting under the dashboard of your vehicle is designed to put heated or air conditioned air right where you want it. Most vehicles have ducts that allow the driver to direct the heated or cooled air toward the floor, the front seat occupants or the inside of the windshield for defrosting, or a combination of the above. Air is forced through various vents in the dash via a series of cable or vacuum operated doors. Usually, the more expensive the vehicle, the more elaborate the duct system.

The cable system is virtually foolproof. Cables rarely have to be replaced during the service life of the vehicle. The first tip-off that something is wrong with a cable usually occurs when it becomes difficult to move the control lever on the control head for the heater and air conditioner. If this happens, the door at the other end of the cable is probably jammed. Don’t try to force the lever or you’ll probably break the cable. Instead, refer to the Haynes Automotive Repair Manual which covers your vehicle, remove the dash or under dash trim plates and try to free up the door.

Some heating and air conditioning systems utilize vacuum lines instead of, or in addition to, cables for actuating the doors. And the latest designs employ electrically actuated doors, or a combination of electrical and vacuum operated doors . These systems are highly complex and their diagnosis and repair is sometimes even beyond the scope of professional mechanics! Service on such systems is best left to an air conditioning technician.

When viewed in its broadest sense, energy takes many forms, manifests itself in many ways and can be transformed from one form to another in many complex ways. But heat is always there in some way. Let’s take a few examples. The sun, obviously, gives off vast quantities of energy, heat being one of the more obvious ones. On a smaller scale, any fire also gives off heat. The connecting rods, crankshaft and drivetrain of an internal combustion engine convert the chemical energy released in the explosion of gasoline vapors into the kinetic energy of the moving automobile, in the process creating a lot of heat because of the friction created by all those moving parts rubbing against one another. And every time the driver applies the brakes to stop the vehicle, the friction generated between the brake pads and rotors, and between the tires and the road, transforms the kinetic energy of the moving vehicle into heat.

But when you hear the word “heat,” do you think of kinetic energy, friction, internal combustion, fires or the sun? Probably not. The first thought that crosses your mind is the palpable effect of heat on your body when you are in close proximity to a heat source. In other words, the word “heat” makes you think of the physiological sensation of being hot. That’s because we humans are pretty sensitive to heat, or the absence of it.

Automotive air conditioning is generally regarded as one of the two most significant contributions by American automotive engineering to the evolution of the automobile (the automatic transmission is the other). At first, air conditioning was an expensive option found only on the most luxurious automobiles.

As time went on, it became more available, and affordable, to the general motoring public. Today, air conditioning systems are such a widely used option that we seldom give them much thought, until they break and we have to fix them. And that’s what this book is all about – how to keep NC systems operating and how to fix them when they break. The heating system has also been included in this volume because it is an integral part of most modern automotive “climate control” systems. In many instances, it’s impossible to work on the air conditioning system without working on the heating system as well. But before we get into maintaining or servicing either system, it’s essential that you know the principles of air conditioning and heating system operation.

Make sure you understand them clearly before you try to maintain, diagnose or repair the air conditioning or heating system in your vehicle. Neglecting the material in this first chapter could get you into trouble later.