How to Fix Marine Air Conditioner Hi PS Error & Trigger Failure

marine ac trigger repair

Fixing a boat AC unit that shows a “Hi PS” error and shutdown due to a faulty water pump trigger [includes VIDEO]

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When you own a [nearly 20 year old] boat you never know what is going to go next. This time it was our marine air conditioner, but luckily it wasn’t a big problem.

The forward AC unit on our Sea Ray boat suddenly stopped running and there was a flashing “Hi PS” error on the control panel. We realized that the water pump was not going on and it was causing the air conditioner to heat up and shutdown of the forward AC unit. It was odd because when the AFT air conditioner would turn on the water pump, but when the forward air conditioner tried to go on by itself it wasn’t working.

We initially went through all the usual troubleshooting steps to determine the problem… like checking the filters and looking for any potential clogs… but then discovered that it actually a marine AC trigger mechanism.

The way it works is that there is one water pump for both the forward & AFT units on our boat and each one has a designated trigger mechanism that will start the water pump when either one of them comes on. But if the AC unit has a faulty trigger mechanism it won’t be able to turn on the water pump when the AC unit needs to run UNLESS the trigger unit for the 2nd AC unit turned on the water pump first.

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How to Replace the Marine Air Conditioner Trigger

Captain Brian explains how he determined the issue and shows the replacement step by step in this how-to video:

Where to Find AC Trigger

We did a simple search online for “Marine AC Trigger” and found several marine parts stores that sell it. Some units require a 115v trigger while other bigger units may require a 230v. We ended up buying a dual voltage trigger that automatically detects voltage required (and actually cost a bit less).

The repair took about 10 minutes and cost less than $100. Now, if we only knew what was coming next đŸ˜‰

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Diane Seltzer

View posts by Diane Seltzer
Diane is the founder of as well as the boating lifestyle site for kids Active in the boating industry, Diane has also led the marketing for multiple recreational boating businesses and startups.
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