Hello TDSI,
There are two K148 which you have discovered located on the top mezzanine and the lower mezzanine. In order to determine what mezzanine the relay that needs to be replaced is on you will have to locate the BANK, Column, and Row the relay is located on. Please take a look at NI Switches Help located in Windows Start>>(All Programs)>>National Instruments>> NI Switch>>Documentation>>NI Switch readme. Under the Device Section specific to the PXI-2532 (screen shot below) please confirm the location of the faulty relay by looking in the topology you are currently using.
For example lets say I am using a 1 wire 4x128 topology and there is a dead relay in Bank 0 (B0), Row 0 (R0), Column0 (C0) of this configuration.
Then I would go to the PXI/PXIe-2532 Relay Replacement page and find B0R0C0 which corresponds to K144 on the bottom Mezzanine.
Please post back if you have follow up questions.
Best Regards,
Izzy O.
Applications Engineer
National Instruments
www.ni.com/support