Error message "PreArm: RELAY_PIN=54, set SERVO13_FUNCTION=-1"

I want to operate 2 relays on AUXOUT5 and AUXOUT6 with TX-Channel 7 and 8.
I set RC7_OPTION to 28 Relay On/Off) and RC8_OPTION to 34 (Relay2 On/Off). After setting RELAY_PIN to 54 (AUXOUT5) I get the Error message in the Data screen: “PreArm: RELAY_PIN=54, set SERVO13_FUNCTION=-1”, arming is not possible and GPS is switched off.
Why Servo 13, I don’t understand the logical connection. SERVO13_FUNCTION is 0, switching it to -1 does not change anything.

Servo outputs 1-14 map to servo 1-8 and the aux channels1-6 = servo 9-14 so when you want to use them for GPIO you have to set them to -1 so its not used for pwm.

I wrote: “switching it to -1 does not change anything”. But I did not reboot the pixhawk. After rebooting it works correctly. Thank you!

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same here, setting to -1 doesn’t solve issue, relay still doesn’t work…

And I can’t save -1 value… it changes to 0 after writing parameter…

post a log so we can check your settings.

1 01.01.1980 2-00-00.bin (208 KB)

hmm, looks like android version of mission planner doesn’t support to set -1, same with QGroundControl
with PC by connection by wire helped =)

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good, is it working now?