Misbehaving Garmin Autopilot

[Jon magowan]

I have a Bavaria 33 cruiser, about 10 years old. I acquired it some months ago. It is fitted with a Garmin Autopilot (GHP 12, GHC 10, Lewmar electric drive motor).

When it works, it’s brilliant and does exactly what I need. Unfortunately it doesn’t always work and, as I often sail by myself, I need a reliable system.

When it doesn’t work, the indications are that the system has engaged normally, however the autopilot is not actually doing anything and the boat is simply drifting out of control. I have recalibrated the system at least twice. It hasn’t helped.

I’m wondering if anybody has seen something similar with this setup, or if anybody can suggest where I might begin to diagnose this problem.

As always, many thanks in advance.

 

[PaulRainbow]

I have a Bavaria 33 cruiser, about 10 years old. I acquired it some months ago. It is fitted with a Garmin Autopilot (GHP 12, GHC 10, Lewmar electric drive motor).

When it works, it’s brilliant and does exactly what I need. Unfortunately it doesn’t always work and, as I often sail by myself, I need a reliable system.

When it doesn’t work, the indications are that the system has engaged normally, however the autopilot is not actually doing anything and the boat is simply drifting out of control. I have recalibrated the system at least twice. It hasn’t helped.

I’m wondering if anybody has seen something similar with this setup, or if anybody can suggest where I might begin to diagnose this problem.

As always, many thanks in advance.

Sounds like the drive, possibly the clutch. Usual first step would be to clean/check all terminals. Might have to send it back for repair.

 

[Tranona]

Issues with Lewmar motors covered extensively on the Bavaria forum
bavariayacht.org/forum/index.php?action=search2

 

[Jon magowan]

Thanks guys. Seems that it’s the drive unit rather than the electronics then ?
Thats a good place to start.

 

[Fr J Hackett]

Very easy to check.

 

[Jon magowan]

Sorry Fr J Hackett. You assume too much !!
Please spell it out for me…….

 

[Fr J Hackett]

Simply applying 12 volts to the disconnected autopilot should confirm if it's working or not if it is then you work backwards.

 

[Jon magowan]

Thank you !

 

[PaulRainbow]

Thank you !

Not exactly what you need to do.

There are 4 wires, 2 for the clutch and 2 for the motor. If you simply apply 12v to the motor it should spin, reverse the polarity and it spins the other way. Problem is, apart from a whirring noise, nothing will happen. You need to engage the clutch first, by applying 12v to it, then supply power to the motor, then the rudder should turn back and forth. Don't try to exceed the rudder travel.

If, with power to both, the motor spins but the rudder does not move, that indicates it is the clutch.

Try the test as close to the motor as you can. if it works, try the tests from the cable at the ECU, if it works from there it could be the ECU. Test for power at the clutch and motor terminals on the ECU.

 

[roaringgirl]

You don't even need to do that, just turn on the autopilot while the boat is moored/anchored, then make adjustments to the magnetic course to steer, if the motor whirrs to turn the rudder, but the rudder angle doesn't change, you know that the clutch isn't engaging. If that's the case then put a multitester across the clutch terminals with the autopilot off, watch what happens when you turn it on.

 

[Jon magowan]

Thanks guys. That all makes sense. I’m glad I came on here. I hadn’t considered the drive motor/clutch. I assumed it must be the electronics. That seems very unlikely now, having listened to you guys.