I have found that these cars built during this time period are prone to having a clearance problem with the compressor clutch. With age and use and decreasing magnetic power the clutch, especially on hot days fails to engage when power is sent to the clutch. The hot weather can cause less power being able to travel to the clutch. The clutch can be serviced and the magnets adjusted closer together. I have found a very easy fix for this problem, especially if you are not familiar with working on these clutches.
If you can locate the two wires running to the clutch on the AC, locate a heavy duty relay at any parts store(usually beteen 10 and 20 dollars). If you cut one of the 2 wires running to the clutch and connect a runner from the car side of the cut to the switch terminal on the relay and use a runner from the + terminal of the battery(make sure you have a negative ground vehicle-in this case your car is) to the BAT lead on the relay. Use a runner from the clutch side of the cut wire to the Load terminal on the relay. Finally connect a runner from the Ground terminal on the relay to a good chassis ground. What this allows to happen is when the control unit sends power to the clutch to engade it, it now is intercepted by the relay which closes and sends power on to the clutch directly from the battery. When the clutch has cycled and the control unit cuts power to the relay(switch terminal) the relay opens and stops flow from the battery. Use a heavier guage wire, I use 10 guage. I have only had one unit that this method did not fix. A good canidate for this repair is a car that the cooling comes and goes. If the freon is low it generally would not cool at all. The hot weather puts a strain on the electrical system so it is a good idea to check the condition of the battery and alternator just to make sure you they are performing to specifications. This is much better than having to replace the clutch(cost wise) and I see a lot of customers who have been advised to replace the compressor assembly because of the failure to cool on regular cycles. You should be able to make this repair in about 30 minutes or less. Remember this is just an example of one type of repair. Without having the vehicle to diagnose in person this is just a suggestion based on seeing others performing in a similiar manner.
Sunday, September 6th, 2009 AT 10:27 AM