Tech Tip: Acura MDX A/C blows hot air

Oct. 3, 2024

Customer brought their 2017 Acura in because their A/C stopped working suddenly.

Related To: ALLDATA

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A customer brought their 2017 Acura MDX off at the shop because their air conditioning (A/C) stopped working. It was working perfectly one day and stopped the next day. Everything else seemed to work fine.

Case details

The technician pulled the vehicle into the shop and observed that the A/C compressor clutch would not engage, and the A/C cooling fan did not operate.

The first thing he did was to verify A/C fuse #17 in the underhood fuse box was good. It was okay so he recovered the refrigerant to find it was slightly low. He recharged the system to the correct amount, but the clutch would still not engage.

Next, he removed the compressor clutch relay to test it and found it was good, so he checked for power and grounds at relay socket. There was 12volts and a good ground, but the relay didn’t click when it was inserted into the socket (with engine running and A/C commanded ON).

When he applied 12V to the A/C compressor clutch relay socket, the clutch engaged, but no pressure split was seen on the gauges. He realized then that the A/C fan wasn’t running so he shut off the engine and checked the main fan fuse. The fuse looked good but there was no voltage at either side of the fuse connector. The problem had to be upstream.

After looking at a wiring diagram in ALLDATA he discovered there was a fuse that powered up the A/C main fan fuse. It was located on the positive battery cable. He checked that fuse, and it was blown.

Confirmed repair

The technician replaced positive battery cable assembly, and the A/C worked like new. Fixed!

About the Author

ALLDATA Tech-Assist Team

The ALLDATA Tech-Assist Diagnostic team is a group of top-notch ASE Master Technicians who have devoted numerous years to the automotive industry as independent shop and dealership technicians, shop owners and a many of them have also been automotive instructors.

Each team member is passionate about helping technicians of all skill levels get vehicles diagnosed and repaired quickly and correctly the first time. Because they help diagnose such a large number of vehicles every day, they are a wealth of experience-based diagnostic knowledge.