240 Liebherr- LTM 1200/1 Oil Pressure in the lower

The oil pressure indicator is showing no oil pressure in the lower of our LTM 1200/1, the oil filters are on top of the engine which we replaced with new filters and they are getting plenty of pressure to the filter, but the indicator remains the same. Any suggestions?

240 Liebherr- LTM 1200/1 Oil Pressure in the lower