Symptoms: AC kicks on, but blows warm air Found issues: AC kicks on and AC condenser appears to turn on (makes noise), but the fan won't spin. A few seconds later, the condenser fan motor overheats (almost too hot to touch), then the reset switch is flipped. If I kickstart the fan, it'll run, but the motor will eventually overheat under 15 minutes and also flips the reset switch. Other details: AC condenser fan spins by hand (long screw driver) fairly freely. From what it looks like, it's either the condenser motor and/or the capacitor. My question is how do I properly diagnose which it is? Before you begin, make sure to pull out/turn off the serviceman switch, and/or turn off the breaker, to remove power to the unit. Once you open the unit, you'll want to discharge the capacitor(s). A charged capacitor can store enough energy to kill you, so you want to make sure you discharge them. To check the motor, you're going to want to check the resistance of the coils in the motor.

To do this, you'll need a multimeter set to measure resistance in Ohms. You'll also have to identify the wires, which will depend on the unit you're working on. Use the schematic printed inside the unit, or in the manufacturer's documentation, to determine which wires are which. You'll want to determine which wires connect to the Common, Run, and Start motor terminals.ac unit filter size Once you know which wires go where, you'll measure the resistance as follows:building hvac units If you sum the value measured between Common and Run, with the value measured between Common and Start. different types of air conditioning unitYou should end up with a value right around what you measured between Start and Run. If the values are way off, the motor is bad.

If any of the readings are infinity (open), it means the coil is broken and the motor is bad. Depending on the motor, there may be multiple speeds. If so, you'll have to measure them as well, to determine if those coils are good. When checking the capacitor, the first thing to do is a visual inspection. If the capacitor is bulging, or has released the magic goo. Then the capacitor is bad, and needs to be replaced. Make note of all the wires connected to the capacitor, then disconnect them. Then set your meter to measure capacitance in microfarads (uF). Touch one meter lead to the terminal marked C (common), and the other to the terminal marked FAN. Hold the leads on the terminals until the meter settles, then take note of the reading. With one lead still on C, put the other lead on HERM. Again, wait for the meter to settle, and note the reading. Compare the readings you took, to the values printed on the side of the capacitor. The measured values should be within the tolerances printed on the capacitor, otherwise the capacitor needs to be replaced.

Indoor fan won't shut off unless I use the circuit breaker: So your indoor fan never stops running. You've checked the obvious... The fan switch on the thermostat is in the auto position, not the on position. You tried turning the thermostat to the off position, nothing works. The only way to get that pesky fan to stop running is to shut it off at the breaker or the Emergency Shut-off switch. Well, if you are going to have a problem with your heating or air conditioning system, this is the one to have! Although your fan never shuts off, your heating and air conditioning still works fine. And if you have allergies, it's better to have your fan running continuosly to filter more air anyway. And keep in mind, it really doesn't hurt the motor or cost more money, running all the time. And lastly, fixing this problem, usually isn't an expensive repair. But having said that, do not ignore the problem and let it linger, call for service. So What Causes This? Usually Only Three Things...

A fan relay that is stuck closed A shorted thermostat cable That is about all there is to this problem. So if your fan doesn't shut off, don't panic - just schedule a service call and have it repaired. Tell me when this thread is updated: Jeep Grand Cherokee Discussions Jeep driver door won't open or unlock 4.7 liter wont start when hot 2005 jeep grand cherokee 5.7L stalling and surg...My headlights flicker off and on! 1995 Jeep Grand Cherokee 4x4 problems???????? Jeep has the "Herky Jerky" 1998 Jeep Grand Cherokee light problem. Find what you want! Search Jeep Grand Cherokee Forum Now FAN DOESN’T RUN - The furnace fires, but the blower does not start. After the burners have ignited, the next step in the heating cycle is starting of the blower motor.  This will be done either by a heat-activated switch or internal timing of a control board.  In either instance, the blower motor should start within 30 - 90 seconds after burner ignition.