Problems logging data from thermocouple multiplexer to SD data logger

Please no lectures I work at a university and am trying to build an arduino based data acquisition module to process monitor some solar water heaters for R&D purposes. The other option is to deploy very expensive national instrument equipment.

My problem is that the MULTIPLEXER which reads multiple thermocouples, prints expected temperature values to the serial monitor, however when writing then to an SD card all values are 0.00.