This finally works.
Lights up 4 red leds when above 40C, green <=40
Bed and T0 heater are set to 4 leds each.

Make sure each if and elif M150 conmmend has a beginning space

; dameon.g
; Adafruit #1426 8 led neopixel
G4 P500 ; 500ms delay
if heat.heaters[0].current > 40     ; temp
 M150 R255 P10 S4 F1     ; set first 4 red
elif heat.heaters[0].current <= 40
 M150 U255 P10 S4 F1     ; set first 4 green
if  heat.heaters[1].current > 40    ; temp
 M150 R255 P10 S4 F0     ; set second 4 red, and done
elif heat.heaters[1].current <= 40
 M150 U255 P10 S4 F0     ; set second 4 green and done

This is in my config.g to make sure the NEOPixels are off

M150 R0 U0 B0 P5 S8 F0                                   ; shut off neopixel

@uca I dont't one. One way is when you home one, make sure the other isn't triggered. For example: in the homeall.g file: home x, move x away from the endstop so it's not triggered, home z. Just put a move away form the endstop for one, to use the other. You may have to connect them to both endstop connectors until the firmware can freely assign endstops.

@Roy Remove the bang, !, in front of the zprobe.in the M558.

@army61 One wire to the ground pin and the other to the signal pin. The 3.3v pin is not used.

Go to System and use the "upload system files button" in DWC2.

@TLAS For number 4. You could use this https://www.amazon.com/gp/product/B01HU7BX42 on the supplied wire connector.

Fan 1 defaults to thermostatic. Did you turn that off?

https://duet3d.dozuki.com/Wiki/Connecting_and_configuring_fans

To me, it looks like it is under extruding and the Z0 isn't close enough to the bed.

Update:

The pi4 was showing the low voltage lightning on the screen. Now powering from a 5vdc Meanwell.

@tetele Sounds like the bed is warping when it heats up. The bed mounts needs to be able to allow the bed to expand.

@jay_s_uk Dang computers. Removing the : fixed it.

@dc4Z M671 Returns: leadscrew coordinates are not configured
But I do have a M671 defined.

Error: This kinematics does not support auto-calibration

Cartesian printer. Duet Mini 5+ in standalone, with 1LC both have 3.3RC2. Z motors on drivers 2 & 3. Used the wiki to set it up.

Autolevel Macro:

if !move.axes[0].homed || !move.axes[1].homed || !move.axes[2].homed
 G28 ; home
G30 P0 X20 Y140 Z-99999 ; probe near a leadscrew, half way along Y axis
G30 P1 X270 Y140 Z-99999 S2 ; probe near a leadscrew and calibrate 2 motors

It runs fine then I get the error.

M671 in in the Custom settings section.

Config.g:

; Configuration file for Duet 3 Mini 5+ (firmware version 3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.2.3 on Sun May 16 2021 12:00:09 GMT-0400 (Eastern Daylight Time)

; General preferences
G90                                                       ; send absolute coordinates...
M83                                                       ; ...but relative extruder moves
M550 P"M-Max"                                             ; set printer name
M669 K0                                                   ; Cartesion mode

; Network
M552 S1                                                   ; enable network
M586 P0 S1                                                ; enable HTTP
M586 P1 S0                                                ; disable FTP
M586 P2 S0                                                ; disable Telnet

; Drives
M569 P0.0 S1                                              ; physical drive 0.0 goes forwards
M569 P0.1 S1                                              ; physical drive 0.1 goes forwards
M569 P0.2 S0                                              ; physical drive 0.2 goes backwards
M569 P0.3 S0
G4 S1
M569 P121.0 S0                                            ; physical drive 121.0 goes backwards
M584 X0.0 Y0.1 Z0.2:0.3 E121.0                                ; set drive mapping
M350 X16 Y16 Z16 E16 I1                                   ; configure microstepping with interpolation
M92 X88.10 Y88.10 Z2133.30 E836.00                        ; set steps per mm
M566 X600.00 Y600.00 Z60.00 E600.00                       ; set maximum instantaneous speed changes (mm/min)
M203 X15000.00 Y15000.00 Z180.00 E6000.00                 ; set maximum speeds (mm/min)
M201 X4000.00 Y4000.00 Z150.00 E750.00                    ; set accelerations (mm/s^2)
M906 X1000 Y1000 Z800 E1200 I30                           ; set motor currents (mA) and motor idle factor in per cent
M84 S30                                                   ; Set idle timeout

; Axis Limits
M208 X0 Y0 Z0 S1                                          ; set axis minima
M208 X300 Y280 Z200 S0                                    ; set axis maxima

; Endstops
M574 X1 S1 P"io5.in"                                      ; configure active-high endstop for low end on X via pin io5.in
M574 Y1 S1 P"io6.in"                                      ; configure active-high endstop for low end on Y via pin io6.in
M574 Z1 S2                                                ; configure Z-probe endstop for low end on Z

; Z-Probe
M950 S0 C"121.io0.out"                                    ; create servo pin 0 for BLTouch
M558 P9 C"^121.io0.in" H5 F120 T6000                      ; set Z probe type to bltouch and the dive height + speeds
G31 P500 X20 Y0 Z0                                        ; set Z probe trigger value, offset and trigger height
M557 X5:300 Y5:280 S40                                    ; define mesh grid

; Heaters
M308 S0 P"temp0" Y"thermistor" T100000 B4092              ; configure sensor 0 as thermistor on pin temp0
M950 H0 C"out0" T0                                        ; create bed heater output on out0 and map it to sensor 0
M307 H0 B0 S1.00                                          ; disable bang-bang mode for the bed heater and set PWM limit
M140 H0                                                   ; map heated bed to heater 0
M143 H0 S120                                              ; set temperature limit for heater 0 to 120C
M308 S1 P"121.temp0" Y"thermistor" T100000 B4725 C7.06e-8 ; configure sensor 1 as thermistor on pin 121.temp0
M950 H1 C"121.out0" T1                                    ; create nozzle heater output on 121.out0 and map it to sensor 1
M307 H1 B0 S1.00                                          ; disable bang-bang mode for heater  and set PWM limit
M143 H1 S300                                              ; set temperature limit for heater 1 to 300C

; Fans
M950 F0 C"121.out1" Q500                                  ; create fan 0 on pin 121.out1 and set its frequency
M106 P0 C"Parts" S0 H-1                                   ; set fan 0 name and value. Thermostatic control is turned off
M950 F1 C"121.out2" Q500                                  ; create fan 1 on pin 121.out2 and set its frequency
M106 P1 C"Hotend" S1 H1 T45                               ; set fan 1 name and value. Thermostatic control is turned on

; Tools
M563 P0 D0 H1 F0                                          ; define tool 0
G10 P0 X0 Y0 Z0                                           ; set tool 0 axis offsets
G10 P0 R0 S0                                              ; set initial tool 0 active and standby temperatures to 0C

; Custom settings
M950 F0 C"out1" Q500                                      ; create fan 0 (parts) on pin out1 and set its frequency
M376 H5                                                   ; taper bed compensation
;M572 D0 S0.05                                            ; pressure advance
M207 S1.5 F6000	R0 Z0.03                                  ; firmware retraction
M593 F23                                                  ; set dynamic acceleration
M671 X0:280 Y:0:0 S0.75		                                ; define the two Z leadscrew test-positions and max correction of 0.75
G10 P0 S0 R0                                              ; set T0 heater off
M150 R0 U0 B0 P5 S8 F0                                    ; shut off neopixel


; Miscellaneous
M575 P1 S1 B57600                                         ; enable support for PanelDue
M501                                                      ; load saved parameters from non-volatile memory
M911 S23 R24 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000"        ; set voltage thresholds and actions to run on power loss
T0                                                        ; select first tool

@tazla Use M119 to make sure the endstops are working as intended. It appears the board thinks you're already at the endstop.

@tazla Do you have them set as active high? M119 should only show them as stopped when the endstop is depressed.

My X & Y are NC and are set as:
M574 X1 S1 P"io5.in" ; configure active-high endstop for low end on X via pin io5.in
M574 Y1 S1 P"io6.in" ; configure active-high endstop for low end on Y via pin io6.in

@tazla How do have them wired? Using the NC connections helps with noise.

@lbi Yes for both.

@war4peace Run M98 P"config.g" to see if there are any errors. Mine got stuck connecting once, when a random gremlin decided one day to make my config.g zero bytes.

@ap742 The hotend would have to go outside the bed to allow the Z probe to reach X300. If you have room on the X axis, make the bed bigger in X, and the mesh bed size bigger. Test to make sure you didn't go to big.

@norwestie Without a config.g with the networking commands, networking won't be enabled