Dodge A/C Compressor Failure, DIY Diagnosis & Fix

I encountered a similar issue with my 2013 Dodge 500 last summer. Having some experience with car repairs, I initially thought it was just a refrigerant leak, but it turned out to be more complex. The symptoms matched yours exactly, no A/C operation and the compressor refusing to engage. The workshop diagnosed it as an undervoltage problem affecting the pressure switch and relay system in the air conditioning circuit. The electrical issue was causing the safety systems to prevent the compressor from engaging. The fix involved: Testing the voltage across the system, Replacing the faulty pressure switch, Checking the belt tensioner, Recharging the A/C system Total repair cost was 240€, which included parts and labor. The HVAC system has worked flawlessly since the repair. Before suggesting more specific solutions, could you provide: The exact engine variant in your Dodge, Whether youve noticed any other electrical issues, If the A/C worked intermittently before failing completely, Current mileage on the vehicle This information would help determine if youre dealing with the same underlying issue I experienced.

Thanks for the detailed response. My car has 142866 KM on the odometer. After reading your experience, Im now wondering if my A/C compressor issue might also be related to the pressure sensor system rather than just the relay switch. The symptoms started suddenly, no intermittent issues beforehand. No other electrical problems noted, and my last service was just 2 months ago where they did a general inspection but didnt check the HVAC system specifically. A voltage test sounds like a logical next step before replacing any parts. Did your repair shop test the relay switch connection points separately from the pressure sensor during diagnosis?

Thanks for the additional details. Yes, in my case, the shop did separate testing of both the relay switch and pressure switch components. The voltage testing revealed the pressure switch was sending incorrect signals, which made the system think there was a pressure problem when there wasnt. Your symptoms being sudden rather than intermittent actually matches my experience too. Its a common characteristic of pressure switch failures in these Dodge models, they tend to fail completely rather than gradually. The A/C compressor often gets blamed initially, but the root cause is usually in the control circuit. The voltage testing showed: Normal readings at the AC relay, Inconsistent voltage at the pressure switch, Proper power supply to the compressor clutch Since your mileage is close to what mine was when this happened, and given the identical symptoms, Id strongly suggest having both the pressure switch and AC relay tested before replacing the compressor. In my case, the pressure switch replacement restored proper operation of the HVAC system without needing more extensive repairs. One tip from my experience: make sure they check the refrigerant pressure while testing these components, as low refrigerant can trigger similar symptoms through the safety cutoff system.

Thank you for explaining your diagnosis steps. The separate testing of relay switch and pressure switch connection points makes sense for pinpointing the exact issue. Based on your experience, I'll have my mechanic focus on testing both components thoroughly. Your point about checking refrigerant pressure during component testing is especially helpful since it could save unnecessary parts replacement. I made an appointment for tomorrow to have them perform voltage testing across the air conditioning system, with specific attention to the AC relay and pressure switch readings. They'll also check the refrigerant levels like you suggested. The sudden failure of my system does seem to match the pattern you described with pressure switch issues in these models. Very helpful to know that the pressure switch was the culprit in your case rather than the A/C compressor. That could save me significant repair costs if I have the same underlying problem. I'll update once I get the test results back from the shop.