Illustration from a solid state "relay" product

{{:ssr:dc-dc-ssr.jpg?400|}}

Power is going in at 'plus' and leaving at 'minus', at the "out" terminals of the Solid State Relay.


And here is a simplified schematic of the internals of a DC-DC SSR


{{:ssr:internal-dc-dc-ssr.jpg?600|}}


Notice the diode inside the MOSFET symbol?  It goes from - to + 

The diode is a natural effect of the way a MOSFET is made, and not something that is put there as an extra ting.


So I would say, try again, but this time with power going from + to - on the SSR's 


Sources: [[https://electronics.huimultd.com/Blog/How_to_wire_SSR/|How_to_wire_SSR - Point 4.1]] 

**After thoughts:** 

Since we are trying to make +24V available to the "-" out of the SSR, then the SSR must internally have a High-Side driver chip, that triggers the MOSFET Gate, as Gate voltage must be some 10V-15 higher than the "-" out side of the mosfet (the Vgs voltage).

See also this image of a High-Side driver: 

{{:ssr:high-side_switching.jpg?600|}}


Most likely the SSR will have an internal High-Side driver chip included in its belly. 

Sources2: [[https://www.infineon.com/cms/en/product/power/gate-driver-ics/high-side-drivers/|Infineon.com High-Side drivers]]