Air conditioning electrical
Automobile air conditioning electrical problems are not as common as AC leaking problems, but I have seen them enough to warrant a page about it. Pictured to the right are the three main components of an electronic compressor clutch assembly. The belt driven pulley (middle), the electromagnetic clutch coil (right) and the compressor clutch itself (left) that locks the unit on command. When the clutch is applied it turns a drive-shaft that runs the compressor.
Electrical systems on any part of an automobile are susceptible to poor connections and corrosion despite the modern weather resistant connectors deployed throughout the vehicle. As I spoke about before on previous pages a good visual inspection is a good place to start with many car problems. Below I will give you some specific examples of things you can visually inspect plus a few helpful tips for electrical diagnosis on automotive air-conditioning systems.
Automotive air conditioning electricalBecause auto air conditioning systems contain various switches and relays there will be times when one of them will not function. Sometimes this is not even due to the component itself but is caused instead by a bad connection or corrosion that has built up on the leads.
The air conditioning systems on today’s automobiles are loaded with switches. A few examples would be a low-pressure cut off switch, high pressure cutoff switch, power steering cut off switch, wide open throttle cut out switch. Also the Interior switches such as the AC on/off switch and the blower control that is a multi-position switch. If any of these switches malfunction or have poor contact at the connectors the driver complaint will most likely be the air-conditioning system does not work. I have said it before but please remember you should always consult your car repair manuals for the specifics of testing the system on your particular vehicle. The factory manual is better then any forum or static web page that you will run into (including this one).
Air conditioning electrical componentsThe compressor clutch is an electromagnetic unit that is energized by a coil that actually pulls the clutch in to grip against the belt driven air-conditioning pulley. You can test the electrical portion of the compressor clutch with an ohmmeter. There will be a specific resistance value for your vehicle. But often I will find the compressor clutch coil will have an open in it and that is easily tested with a automotive multimeter. If there is no resistance value registered on the meter (or OL) then this is most likely your problem. Replacing the compressor clutch can be a touchy operation. The gap between the clutch material and the air-conditioning pulley is very critical.
In most cases this air gap should be between .35 mm and .85 mm. Again, this will vary with your model automobile. But my point of this discussion is if the air gap is too large, the clutch will slip when it is engaged. If the air gap is too small the clutch material will start to wear quickly as it will not fully release from the compressor pulley as it spins. This can also cause strange air conditioning noises with the panel switch in the off position.
I have a page that describes not only how your car removes the heat from the passenger compartment but also shows a good diagram of how automobile air conditioning works. The preceding electrical problems are just a few of the common ones I have seen recently. There is a lot of other stuff that can go wrong with automotive air-conditioning. The best way to diagnose problems is to understand how it works. This next link will take you from this page about air conditioning electrical problems to the main car AC page.
 Custom Search The You fix cars home page is a great place to go to find out what else is covered on this automobile repair website. You can also learn more about the car mechanic that built it and why he thinks that some people can perform their own Diy automotive repairs |