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Surfgate relay module rebuild on 2016 A20


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Surfgate relay module on a 2016 A20 can be replaced/rebuilt with off the shelf parts.

For over a year, my 2016 A20 surfgate system had been misbehaving. At the end of surfing left, the starboard surfgate would occasionally not return in. Situation degraded and quit deploying out most attempts. Port gate continued to work perfect. Calibrate would run both sides in; service mode would only push the port gate out. Surfgate relay module was bad, so I fixed it.


  • Enjoying DIY maintenance, I decided to get out the multimeter and test wires; by the time I finished testing, the relay module was fully dysfunctional.
  • If you find yourself in this situation, then take your boat to your marine service center for repair.
  • If you enjoy DIY repair tasks, I still recommend take your boat to a marine service center for repair.
  • If you choose to ignore the above advice and repair the relay module DIY, then the following information may assist.
  • After doing this repair, my surfgate system has been working flawlessly on both sides 3 weekends in a row!

Overview of relay module:

  • The relay module contains 4 relays sealed in epoxy keeping them from being individually serviced.
  • Connections include 5 wires to a connector toward the control module, 2 wires to a connector toward the port actuator, 2 wires to a connector toward the starboard actuator, and 2 wires toward 12 volt power & ground.
  • Each actuator has a smaller 2 wire connector for sensing gate position; these go to the control module, not the relay module; wires closed indicates gate is in and open indicates gate is out.
  • The relays are activated individually for movement of starboard out, starboard in, port in, port out.
  • Calibrate mode simultaneously activates starboard in and port in relays; service mode simultaneously activates starboard out and port out relays; under normal operation, only one relay activates at a time.

Needed parts, tools, skills, and such:

  • Plan on at least 4 hours total time whereby it is consumed 30 minutes to remove module and harness, 2 hours to splice wires, 1 hour to double-check everything, and 30 minutes to reinstall.
  • Need 4 of waterproof high current sealed relays. Example is 80/60 amp waterproof relay and harness kit with 12 gauge wires from Amazon. Do not use the lower 40/30 amp as this came from factory and I suspect load capacity was marginal.
  • Need 4 of diodes for relay release voltage shunting. Example is 1000 volt 10 amp axial diode from Amazon. These are higher capacity than needed for this purpose, but cost only a few cents more for exceptional durability.
  • Phillips screwdriver to remove the relay module.
  • Adjustable wrench to remove power & ground wires.
  • Diagonal cut pliers or other suitable tool for cutting wire ties and 10 gauge wires.
  • Soldering gun or other means to join wires. Getting a good connection between wires is the most time consuming part of this project; reliability is the goal. I have less luck with crimp connections or wire nuts in a marine environment, so I tend to avoid them or solder in addition to the crimp.
  • Silicone self-fusing tape and/or heat-shrink tubing over each wire joint. I used both and electrical tape to make splice joints water resistant.
  • Experience with wire splicing and taping is needed to ensure solid safe connections.
  • Do not attempt this project without knowing how to make good safe connections between wires!

Steps to rebuild relay module:

#1 – Take photos of the relay module, wires, and all connections for reference.

#2 – Shut off the battery switch.

#3 – Remove the relay module and its wiring harness from the boat and move it to less cramped work area. Three cables have connectors (port actuator, starboard actuator, control module) and the power/ground have lugs with nuts holding in place. Tie a small rope to the power wires before pulling out from under the floor; rope should be left in place in the boat and then used to pull the power wires back through into place when reinstalling.

#4 – Confirm the following 11 wires on the relay module before proceeding.

Lug end:
  Red, 10 gauge, power.
  Black, 10 gauge, ground.

2-pin connector:
  Red/Green, 12 gauge, port actuator.
  Red/Blue, 12 gauge, port actuator.

2-pin connector:
  Orange/Blue, 12 gauge, starboard actuator.
  Orange/Green, 12 gauge, starboard actuator.

8-position connector having 5 wires:
  Purple, 16 gauge, relay power.
  Red/Green, 16 gauge, port out.
  Red/White, 16 gauge, port in.
  Orange/Black, 16 gauge, starboard in.
  Orange/White, 16 gauge, starboard out.

#5 – Confirm the 4 new relays have the following harness wire colors:

  White – coil pin 85
  Black – coil pin 86
  Blue – common pin 30
  Red – normally closed pin 87a
  Yellow – normally open pin 87

#6 – Label the 4 new relays “SO”, “SI”, “PI”, and “PO”. The letters represent Starboard, Port, In, and Out.

#7 – Cut all 11 wires on the relay module an inch from the module. Set the module aside not to be used again. All harness wires will be used in the following steps.

#8 – Connect total of 4 diodes, one to each of the relay coil white & black wires as follows. Don't tape these up until after step 10 because additional wires will be added.

  Banded end of diode --- White wire
  Other end of diode --- Black wire

#9 – Connect all 4 relay White wires to the harness single Purple wire.

#10 – Finish the coil side of the relay connections with these 4 additions. Tape all completed connections when this step is finished.

  SO-Black --- Orange/White
  SI-Black --- Orange/Black
  PI-Black --- Red/White
  PO-Black --- Red/Green

#11 – Connect all 5 of these wires together for power:

  SO-Yellow --- SI-Yellow --- PI-Yellow --- PO-Yellow --- Red.

#12 – Connect all 5 of these wires together for ground:

  SO-Red --- SI-Red --- PI-Red --- PO-Red --- Black

#13 – Make each of the following 4 connections for the actuator side of the relay connections.

  SO-Blue --- Orange/Green
  SI-Blue --- Orange/Blue
  PI-Blue --- Red/Blue
  PO-Blue --- Red/Green

#14 – Tape all connections for electrical and water protection.

#15 – Install the rebuilt relay assembly into the boat restoring all plugin connectors and power connections. Add wire ties & coverings as needed to keep the installation tidy and protected.

#16 – Go through the Surfgate Calibrate and Service items before starting the boat to confirm gate operation.

First time deploying each side should be done without surfing to ensure proper operation. The port and starboard actuator connectors could be inadvertently swapped causing issue for the control module. If this happened, swap the actuator connectors back to their original side.

Surfs Up!

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Having the new relay module ready to swap in immediately will make the task go quickly!  Mine has 330 hours. I suppose if my rebuild lasts to 660 hours I’ll be quite happy. 

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5 hours ago, Stevo said:


i am replacing my 2017 relay module tomorrow because of your same problems (300hr mark). i am lucky enough to still be under warranty tho.

Are you building it @Stevo or getting a factory module?

@atLakeSantee I'm trying to draw out your explanation in the form of a relay diagram, and I'm getting a little hung up.   

it sounds like it's pretty close to this one, except that the inputs aren't reversed (both going to pin 86, rather than having one relay normally open and one normally closed)


can you or someone else (maybe @justgary??) esplain how the relay box is working and what the diodes are doing?

I've always wanted to pull a trigger signal from the SG Out pulse to run a momentary sg horn on my not-so-equipped axis.  


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16 minutes ago, shawndoggy said:

Are you building it @Stevo or getting a factory module?

@atLakeSantee I'm trying to draw out your explanation in the form of a relay diagram, and I'm getting a little hung up.   

it sounds like it's pretty close to this one, except that the inputs aren't reversed (both going to pin 86, rather than having one relay normally open and one normally closed)


can you or someone else (maybe @justgary??) esplain how the relay box is working and what the diodes are doing?

I've always wanted to pull a trigger signal from the SG Out pulse to run a momentary sg horn on my not-so-equipped axis.  


Factory replacement part, i already swapped out an actuator, but that didn’t solve the problem, so the relay module was the next logical replacement.

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@Stevo, if you hear both actuators run when doing both Calibrate (move gates in) and Service (move gates out), but one does not physically move out for Service or in for Calibrate, then actuator would likely be bad.  If you hear an actuator during only one of Calibrate or Service, then most likely the relay module.  If you don't hear it trying for either Calibrate or Service, then could be either the relay module or the actuator; swap actuator connectors left/right then do Calibrate and Service again; if opposite is now dead, then bad relay module most likely; if same side dead, then bad actuator.

@shawndoggy, your diagram is a simplified version of what's going on.  Certainly the relay module is twice that having a relay pair for each actuator.  It's missing the diodes and the inconsistency of 85/86 is messy.  Without the diode across 85-86, the relay won't last long due to some physics going on there; for more info on this lookup Flyback_diode on Wikipedia.  These diodes cannot help with your horn idea; although, that would be an easy project if you don't mind the horn sounding for the few seconds it takes for the gate to deploy outward; sounding for only a quick beep gets a little more complex.

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@atLakeSantee was the current relay module built your way with four five pin Bosch relays and the four diodes, or was it a custom module and you just figured out a way to make it work?

I think I understand the back feed prevention on the diodes… the diodes are just going on the trigger wire for each relay so that the relay won’t back feed the input to the SG controller module, right?

my idea for the sg horn was to use a programmable relay like the PAC TR7 Pro (which is now unfortunately discontinued)  but if I understand your description correctly I might just be able to pull the trigger signal from pin 30 of the PO and SO relays and run those to trigger another relay to a moped horn.  Suppose I could even put the horn on a flasher relay to pulse?

im pretty thick in the head and some pics would really help!

Edited by shawndoggy
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Initially I would get a surf gate error on the port side gate (surf right ) on the screen. It was intermittent and would often retract eventually. It progressively got to the the point where it would happen every time. This went on for about a year, dealer said they couldn’t “replicate “ the problem and therefore didn’t fix anything, when I dropped it off for other minor warranty repairs.

about a month ago the service mode , calibration, re-boot “hack” didn’t work and  we had to put in service mode to get to the launch and load on the trailer. Once I got back home I had to use the bleeder valve on the actuator to get the gate to retract manually.

orderd up a new actuator, swapped it out, and about 30 min into surfing the same error popped up on screen.  it did eventually retract, using service mode and calibration. So that’s how I ended up pointing the finger to the relay module.

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@shawndoggy, my boat had the factory relay module which was about 4"x6"x1.5" black plastic rectangle dish shape half filled with epoxy.  Extending out of the epoxy fill was the 11 wires plus the tops of 4 standard 5-pin Bosch-style relays.  I do not know if diodes were embedded in the epoxy; however, due to the physics of how the coil of the Bosch relays work, they MUST be accompanied by a voltage spike protector of some sort; diodes work great for this purpose, so I decided to add one for each knowing a diode can peacefully exist even if the system was built with spike protector located in the control module (less likely) or the relay module (more likely).  Each diode is in parallel (not in series) with the relay coil such that it is not shorting the 12 volts to ground.

For gate horn timer, Amazon sells a few different relay timer boards that would work similar to the TR7-PRO; most have built-in LED display so can be programmed without a computer.  Tapping in to pin 30 of the PO and SO relays should work great as you suggest.  Your two new wires could have a diode in each to merge into one wire going to your timer or directly to the horn.  The horn ground could connect to any ground wire; does not need to go back to the actuator wires.

Trying to include links or photos here; not sure if this is going to work...   Original module.    Completed rebuild.


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