Can the Air Conditioner and Ignition Be Started Together?
2 Answers
The air conditioner and ignition cannot be started together. Reason: The compressor of the vehicle's air conditioner operates only when driven by the engine. Starting the engine while the air conditioner is still on increases the load on the starter. If the battery is not fully charged and is in a weak state, the battery power will noticeably decrease, making it harder to start the vehicle (manifested as a drop in the starter's rotation speed when turning the engine). This phenomenon is not noticeable when the battery is fully charged. Consequence: Starting the vehicle with the air conditioner on increases the starting load, which in turn raises the current, potentially causing wires and connectors to overheat. The starter fuse might also blow as a result.
I've been paying attention to this issue since I started driving trucks twenty years ago. In older vehicles, the current was very tight during startup, and if the air conditioning kicked in simultaneously, all the dashboard lights would dim momentarily. Although modern cars have larger battery capacities, voltage fluctuations during startup still exist. Just last week, my neighbor's SUV ruined its battery because of this. Personally, I recommend turning off the air conditioning knob before starting the engine and waiting until it runs smoothly before turning on the AC. Developing this habit can protect the starter and extend the battery's lifespan. This is especially important during cold winters when battery performance declines. Every day before driving, I check the air conditioning switch status—it only takes two seconds.
