1998 GMC Savana PCM and Fues box

I have a 5.7L GMC Unique Conversion GMC1500 SAVAN My power control module (PCM) was recently replaced due to corrosion and continues to corrode after one month of installation. The PCM is on the other side of the engine compartment away from the battery. The brake fluid reservoir is directly above the PCM but is completely dry. Yesterday I pull my fuel relay because I wanted to test my fuel pump amperage and with no leads connected and no fuel relay my vehicle was able to run I thought it was weird so I allowed it to idle for about 5 min and I accelerated the vehicle and it continued to run. It obviously there is something wrong but this is above my experience level. Can you provide me some info of what it might be?