I have a Honeywell thermostat. The thermostat clicks to turn the air condition on but the outdoor unit does not turn on. The fan clicks on though.

It sounds like there may be an issue with the Honeywell TZ4 thermostat and the cooling system connected to it. Based on your description, it appears that when the thermostat calls for cool, the cool light turns green briefly, then turns off with a clicking sound. Additionally, the first air conditioner unit clicks but does not turn on, and the outdoor unit clicks, the fan moves for a second, then stops.
This could be caused by a variety of issues, including a malfunctioning thermostat, a problem with the wiring between the thermostat and the air conditioner, or a problem with the air conditioner unit itself.
To troubleshoot this issue, I would recommend checking the following:

• Check the wiring between the thermostat and the air conditioner to make sure it's not loose or damaged.
• Check the thermostat to make sure it's functioning properly.
• Check the air conditioner unit for any visible damage or malfunction.
• Check the compressor, it could be a failed compressor that is not running.

If the problem persists after checking these things, it's best to call a professional technician to diagnose and fix the problem as it might require specialized knowledge and skills.

First of all, fan on the tstat (on or auto) is referring to the blower fan not the outdoor fan. For the outdoor fan to run system must be set on cool and the setpoint temp must then be lower than the room temp. So what you are saying is the unit begins to work when you kick it??? Possibly you have a lose wire somewhere, check all connections outside. What type of checks have you performed on the capacitor?

Serena, more than likely the problem is with the system and not with the thermostat. Either the a/c compressor is not running or there is a loss of refrigerant issue or a safety device in the cooling circuit has the unit shut off.

Verify that the system components are running or not running...indoor blower, outdoor fan and a louder hum inside the outdoor unit that would be the compressor. If any of the components are not running it is time to call for service.

Its probably not the thermostat. The air conditioner may be stuck on heating mode. If its a reverse cycle, the reversing valve may be jammed so even when the thermostat is calling for cold air, it stays on heat. If the machine is on heating mode, it should be blowing cold air out of the outdoor unit of the air con. If its on cooling mode, the outdoor should be blowing hot air.

What sort of air con is it? If its a split or ducted with a separate outdoor unit, does the outdoor fan start ?

Can I start by saying I am not in anyway saying to do this alone it is dangerous but if u must follow each step start by being safe shut off the breakers good luck here to help
Step 1
Turn the air conditioning and heating unit off by flipping the appropriate circuit breaker. Test the unit to make sure it's off by turning your existing thermostat to the "On" position and seeing if it turns on. Wiring a Honeywell thermostat when the circuit breaker is on could cause you to blow the transformer that powers the HVAC unit Step 2

Connect the red wires to the thermostat RH, thermostat RC or thermostat R terminal. The thermostat RC terminal has a jumper wire between thermostat RH and thermostat RC. The thermostat R terminal operates both the heating and cooling units, and contains an internal jumper wire. Basically, your red wire on a Honeywell thermostat is the hot wire that run. Step 3

Run the green wire to the thermostat G terminal. The green wire controls the relay that operates the blower, and it controls the fan. Step 4

Control your air conditioning when you connect the yellow wire. It connects to the thermostat Y terminal Step 5

Hook the white wire to the thermostat W terminal to control the heating unit

I'm not sure if the thermostat is wired correctly. First, the thermostat is wired directly to the outdoor unit (compressor/condenser unit). It is NOT directly connected to the indoor unit. It connects to a low voltage control panel in the outdoor unit that sends a signal to your indoor fan/evaporator. This wire is called the fan relay switch and physically runs between the low voltage controls of the indoor and outdoor units. If the fan relay is bad it's possible that the unit runs continuously. To prevent destroying your outdoor unit there is a safety feature that prevents the indoor fan from shutting down while the outdoor unit is running. If the indoor fan did shut down while the outdoor unit was running than you would slug your compressor. That is, your compressor normally sees refrigerant gas but is instead seeing refrigerant liquid. That would not be good since this scenario would destroy your compressor. It sounds like a faulty fan relay. The actual contactor portion of the relay is in the outdoor unit.

There seems to be a problem with the wiring of the thermostat. Apparently the thermostat is calling for cool (if wired properly), but is not being satisfied. The thermostat is just a switch. When there's a call for cool, the thermostat sends 24-28 volts to the contactor (inside the condensing unit to start the compressor and outdoor fan). The indoor fan is energized through the fan relay (inside the air handler). When the temperature in the conditioned space reaches the set temperature,then the thermostat cuts the power to the contactor and it stops the compressor and outdoor fan. Check that the compressor is actually running, if not, check for 24-28 volts on the wires feeding the contactor, if there is, and the contactor isn't closing then the contactor is defective. If the contactor closes and the compressor doesn't come on, check the capacitor. If the capacitor is good then check your compressor motor. I suspect you have an improperly wired thermostat

Recheck the wires to make sure that you are calling the outdoor unit to cool! Wires that call for cooling are R to Y and R to G calls indoor fan on! This usually happens at the same time in the thermostat when call for cooling is tripped, Green wire turn signal to indoor fan on and Yellow wire fire 24v to the contactor oudoors to the compressor and outdoor fan. Check all wires for contact an breaks.

by the outside unit, you will have a shutoff. pull out the shutoff, and unscrew the cover. 2 cylinder like fuses are inside. It is likely that one or both are bad. When you turn on the AC and the outside fan does not turn on... this is likely this is the solution.