Air Conditioner

Toyota Matrix 2003 Air Conditioning Stop Cooling

Toyota Matrix, 2003 model had the air conditioner suddenly stop cooling. After checking the refrigerant and seeing that it was ok I checked further and found that the compressor clutch was not engaging.

The wires all tested ok and the connections were in good shape so now that all of the easy stuff was checked it was time to get into the meat of the air conditioning system. After checking the circuitry for the air conditioner clutch and relays in the circuit we found that the M/G relay was not operation correctly. The M/G relay is located in the long black fuse box under the hood by the battery. Our M/G relay was small and white in color and plugged in so soldering was not necessary.


The M/G relay was a dealer item costing around $80.00

The parts counter person at Toyota said that they have several complaints about that relay and he is surprised that it hasn't been recalled.

With the M/G relay replaced we had no further trouble with the air conditioner.

2003 Toyota Corolla A/C Doesn’t Cool-Compressor Won’t Start

On my wife's 2003 Toyota Corolla/Matrix XR the A/C suddenly stopped working for no reason. She just pressed the A/C button and no cold air.

After checking into the problem I found that after turning on the A/C the engine RPM would increase as if the compressor was turning on, and the cooling fan would start to run as well. I had found that there were a few reasons for the A/C compressor not to turn on and the first reason was a lack of refrigerant in the A/C system. I checked the refrigerant and it was up to the correct pressure.

I had to run a jumper wire to the compressor clutch directly from the battery to get the compressor to turn on to test the refrigerant pressure and it turned on like it should have so that eliminated the compressor clutch as being the problem. My problem was that there was no continuity from the A/C switch inside the car to the compressor clutch.

After going to the Toyota dealership and asking both parts and mechanics I found out that the 2003 Matrix and Corolla had a potentially defective relay in the A/C circuit, in fact Toyota issued a service bulletin about the problem, not a re-call just a bulletin.

The defective A/C relay is called the M/G CLT relay and it is located in the fuse box under the hood next to the battery. The relay is solid state so you can't take the cover off and check the contacts all you can do is replace it.

The large contacts on the relay are the ones that are connected to the contacts, and the smaller contacts are the power contacts for the relay itself.

A new relay is around $70.00 from the Toyota dealer, an after market relay isn't much cheaper so it would be a good idea to get the dealer relay for the better quality part.

Air Conditioning Ductwork – It Pays To Clean It

During this hot summer that we are having here in Florida, I thought my air conditioner was unable to handle the load.  Even though it seemed to be working right and the compressor had plenty of freon it just seemed to run forever to just keep the house at eighty degrees.  I had called a couple of air conditioner companies to check the unit out and make sure it was operating right and they both said that everything was ok.  The last technician told me that I may want to have my ductwork professionally cleaned since the house was over thirty years old.  We had only bought the house three years ago and there was no history for the air conditioning service.

We decided to take his advice and have the ductwork cleaned.  The duct cleaning company came equipped with a large vacuum cleaner and an air compressor to do the job. What they did was start at the furthest end of the house away from the blower and put the compressed air lines in there along with a device that went down the ductwork blowing the dirt out of all of the nooks and crannies.  On the other end, where the blower normally is, they put the vacuum cleaner to collect the dirt as it was blown through.  When they started I couldn't believe all of the dirt and dust that had been sitting up there.  It was a steady flow of dirt from one end of the ductwork to the other.

They did a real thorough job and when they had finished  I noticed a definite difference in both the air flow and temperature.  Now the house gets cooler much faster without the air conditioner having to work so hard and long to bring the temperature down.  I'll make another post when I get my next electric bill, but I bet it will be a big improvement.