Fault-finding
The AC will not turn on at all
Work outward from the simplest: remote batteries and mode setting, then the breaker and supply voltage, then the indoor board, then the outdoor unit. A surprising share of these calls end at a remote or a tripped breaker nobody checked, so start there before booking anything.
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The remote and the mode
Flat batteries, a unit left on fan mode, a temperature set above room temperature, or a timer left running from last season. Point the remote at a phone camera and press a button — most cameras show the infra-red LED flashing. If nothing appears, the remote is the fault and it costs almost nothing.
Supply, breaker and voltage
Check the breaker and the isolator. Then consider voltage: our supply sags, and many units simply refuse to start below a threshold rather than risking the compressor. A unit that will not start during peak evening load but works fine at midnight is telling you about voltage, not about itself.
Indoor board and display codes
If the unit has power but does nothing, the indoor board or its display may be reporting a code. Read it before pressing reset, because the reset clears it. Codes distinguish a communication fault between indoor and outdoor units from a sensor failure, and those are very different repairs.
Outdoor unit and interconnection
The indoor unit can appear dead when the outdoor unit is not responding, particularly on inverter models where the two communicate. Damaged interconnecting cable, a corroded terminal block, or a failed outdoor board all present this way. This is where a meter is genuinely needed rather than observation.
Why is my AC not turning on?
How do I check whether the remote is working?
Point it at a phone camera and press a button. Most phone cameras render the infra-red LED as a faint flashing light on screen. If you see it, the remote is transmitting and the fault is elsewhere; if you do not, replace the batteries and try again before assuming the remote has failed.
The unit starts, then stops after a few seconds. Why?
That is usually a protection cut-out rather than a failure to start — the unit begins, detects something outside limits, and shuts down. Common causes are a failing capacitor, high pressure from a blocked condenser, or low voltage. Reading the fault code at that moment is what separates them.
Could low voltage be damaging the AC?
Sustained low voltage makes motors draw more current and run hotter, which shortens their life, and it is a real problem in parts of the twin cities during peak load. If the supply is chronically low, a stabiliser sized for the unit is a genuine protection rather than an accessory.
Rather have it done?
AC repair covers units that will not start, trip the breaker, run without cooling, leak water into the room or make a new noise. Callout and diagnosis in Islamabad or Rawalpindi is PKR 2,500, taken off the bill if you proceed, and the repair is priced before any part is fitted.
AC repair and spare parts in Islamabad — prices and scope