Same fix for Brent
No, Brent. The voltage drop is a function of resistance and current. The motor draws more current when engaged than when in standby. So if you have resistance in your wires or connections, when you attempt to draw more current, you'll get more voltage loss.And 12.4 volts at the control unit is not "good" if you have 13.6 at the battery! The control unit draws very little current, so dropping over a volt with miniscule current draw means you have substantial resistance between the battery and the autopilot. The motor draws a lot more current, so there's a lot more drop. Now, if you disconnect the autopilot and just measure the voltage at the wires, you'll get a good voltage. Does that mean the control unit is the culprit? No. It means that now you are drawing no current, so you have what's known as "open circuit voltage". No current, no voltage drop. You get the voltage of the source (13.6 or so). Put anything across the wires, though, that draws current, and your voltage drops. That shows resistance in the lines. If you had good wires and connections, the drop would probably be unmeasurable.Trust me on this one - I used to be an electrical engineering professor. This sounds like you have a bad wiring run / connection problem. Did you use marine-grade wire and connectors when you installed it? Check all the splices and connections - you have a bad run somewhere. Describe your wiring run. And remember, check the ground return as well. The jumper cable test I described earlier will prove it.