Both switches were activated and the high
pressure overpowered the lowpressure??

Don,

 

Not a matter of high pressure overpowering the low pressure.  The pump normally runs in one of two directions that supplies hydraulic fluid to either the low pressure or high pressure port depending on the direction.  Applying plus voltage to both lines causes the pump to run - in what direction???????  I have a old pump out at my hangar and I will perform this power experiment under controlled conditions, perhaps today.

 

Did you note if the transition light was on?