WHEN I SLOW AT AN INTERSECTION THE AC GOES FROM COLD TO HOT
jtaddiken: A/C systems rely on air flow over the condensers and is the component that looks like a radiator. This component is also located in front of the radiator while the fan is behind the radiator. Consequently if it does not function, especially on hot days the pressures in the condenser will build. The condenser is where the freon is condensed from a gas to a liquid. The byproduct is HEAT!
SO, You could have a number of problems occurring. 1. Fuses: in the main fusible link box are located on the left side of the engine compartment. It's a large black box about a foot long and 4 inches wide.When you remove the cover, you will see some fuses with clear plastic tops on them. They will have numbers on them.
The top fuse will have 140 the next two spaces down should be empty. Then there should be a 30, 30, 30, 50, 40, 40, 30.
You want to check the 30 which is the first one in the line as you go down from the 140. Look through the clear plastic top and compare it to the other ones. if the center of it is burned or missing, it is no good.
Pull it out and get a replacement with the same number.
IF it blows again, you have an electrical short which you can either chase down or bring to a professional.
2. Relays: There should be another box or an arrangement with 4 relays. Three will run side by side and one will be at the other end of the box. Based on the schematic I am looking at, they all work in conjunction with each other. The only variable is the condenser fan. But the radiator fan is designed to run whether the A/C is turned on or not. A failure of any one of these will render the condenser fan inoperative.
3. The fan motor has failed. You can do a simple test which you might do before you do check #2. That is, unplug the fan motor and supply it with an external power supply. Both the positive and negative. The negative is supplied through the relay and the other side to the fan is hot all the time.If the motor runs then continue with the other tests, if it doesn't , the motor is bad.
4. The pressure switch. If the pressure switch has failed, it will create an open circuit to the relay that also kills the compressor clutch so the A/C stops cooling. It can be located on the receiver drier or on the high pressure line close to the drier.
One which malfunctions can also keep the Condenser fan from running.
5. An A/C condenser with a lot of debris built up on it. There is significantly more air being forced through the condenser coils than the fan can pull through the radiator, air leaks between the radiator and condenser, thus minimizing the suction through the condenser.
I hope I haven't created a confusing situation rather than a plausible solution. I try to not only solve the problems, but give a basic understanding of how it works and then why it may not work.
Sometimes people will grade me on my assistance. Most of the assistance I have given, has not yielded a "well he helped" OR BOY, this guy should be giving advise in loading rocks!"
Any way, if I have helped and you need further assistance, I would be delighted to assist. Good Luck.
May 06, 2009 |
2002 Toyota Highlander