This "bulb saving feature" was implemented as the bulbs of the SDP are not replaceable
The panel shuts down the power to save on the oil P and oil T warning bulbs when the related side of the hydraulic system pressure drops <200 psi for 5 minutes or more.
Of course the L or R hydraulic system can depressurize before one another. By switching the aux hyd pump to on you increase the hyd P in the R system, thereby activating the oil P and T bulbs. If then you switch the transfer pump to on, the same will happen to the left bulbs.
Hope everything is clear now
