American Offshore Fishing

Simrad Autopilot issue


Jun 26, 2015
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The Simrad AP22 on my 330 is displaying an error message of "compass data missing". According to the manual on page 115, there are 3 things to check - only one compass is connected, so I've checked the connections on the junction box - Not sure what the Interface Menu is. The third is replace compass PCB or interface PCB. Where are these located - I'm assuming in the junction box, but I don't know. Anyone else come across this issue? How else to troubleshoot?

This error was displayed upon purchase of the boat as a known issue, so I don't know the history nor when it last worked. I did also do a reset and dockside calibration which still gave the compass error.

Capt Bill

GreatGrady Captain
Mar 23, 2005
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First State
Grady White Model
As you probably have surmised, if the power & nmea connections to the heading sensor and J3000x are solid, then either the sensor is bad or the interface circuitry of the J3000z AP computer went bad.

Don't know if this is any help, but I just a week ago pulled my Simrad AP11 control head, fluxgate compass and J3000x course computer, and they all work as they should. I only replaced the AP since the linear rudder position senso,r went out, and although I could have simply replaced it for less the $300, I decided to upgrade to a complete new AP system with features I didn't have, but wanted. (Trolling patterns for instance).

The J3000x and heading sensor are the same for an AP11 and an AP22 installation. The difference is just the control head, so if you are interested in the system I just removed, send me a PM.

As I said, unless it's a bad connection or damaged cable, my heading sensor and course computer will more likely than not, solve your problem, and give you a spare.