How to Determine Whether a Compressor Starter is Good or Bad?
4 Answers
The working principle of a compressor is to draw refrigerant from the low-pressure area, compress it, and then send it to the high-pressure area for cooling and condensation. The heat is dissipated into the air through the radiator, and the refrigerant changes from a gaseous state to a liquid state, with an increase in pressure. The methods to determine whether a compressor starter is good or bad are as follows: 1. Use the resistance range (R1 ohm range) of a multimeter to measure. The resistance between the M and S holes should be between a dozen ohms and twenty-something ohms. If the resistance is infinite, it indicates damage. 2. Use the resistance range (R1 ohm range) of a multimeter to measure. Place the starter vertically with the coil at the bottom, insert the red and black probes into the M and S holes of the starter. It should show an open state at this time; otherwise, it indicates damage.
Judging the condition of a car's A/C compressor starter is actually quite simple, and I perform this inspection regularly during repairs. The first step is a visual check: open the hood, locate the starter on the compressor, and inspect the housing for signs of burning, oil stains, or corrosion—all indicators of internal faults. The second step is an auditory test: after starting the engine, press the A/C button; a healthy starter will produce a crisp clicking sound, indicating it has engaged the compressor's clutch plate. If there's no sound or a continuous hissing noise, it's likely faulty. The third step involves using tools: I often use a multimeter to measure the coil resistance, which should typically fall between 5-20 ohms—set the meter to the resistance mode and clip the probes onto the terminals for an instant reading. If the resistance is infinite or extremely low, it means the coil is open or short-circuited and must be replaced. Additionally, check the wiring connections and fuses to avoid misdiagnosis; a faulty starter can lead to A/C failure or severe compressor wear, especially affecting driving comfort during hot summer months. Regular small inspections like these can prevent major issues.
As a DIY enthusiast car owner, I find it quite straightforward to diagnose a starter's condition. I always begin by locating the compressor's starter assembly, then unplug the wiring connector for testing. Using a multimeter to measure resistance is crucial: a healthy coil typically shows around 10 ohms – significantly higher readings or an open circuit indicate burnt windings. I also monitor the activation moment; hearing a distinct click when turning on the AC confirms proper operation, whereas silence or humming suggests issues. Inspecting contacts for carbon buildup or oil contamination is another step – sometimes cleaning alone fixes the problem. Investing in a $20 multimeter pays off by avoiding expensive shop diagnostics. A faulty starter causes inconsistent cooling and accelerates compressor wear. This method has helped me maintain reliable summer AC performance in my vehicle.
From a practical and cost-saving perspective, quickly determining the condition of a starter is crucial. After starting the car and turning on the AC: if there's no clicking sound, the starter might be faulty; using a multimeter, the coil resistance should measure between 10-20 ohms—any significant deviation means it's time for a replacement. A faulty starter can hinder the compressor's operation, leading to cooling failure or even burning out the entire system. Spending thousands on major repairs is worse than investing a few hundred in a new starter. Regular preventive measures, such as checking wire connections and avoiding prolonged exposure to sunlight, can extend its lifespan.
