Good Day: Below is a link to Technical manuals for your generator. Several members have tried to point you to the probable issue. Step 1: Click on the link, and down load everything for your MEP-1030 generator. You will find what you need in TM 9-6115-749-24&P Work Package 0009, Pages 0009-4 and 5.
MEP-1030/1031 AMMPS 5KW 6115-01-561-7329 (3rd generation generator) TM 9-6115-749-10 (operation) TM 9-6115-749-24&P (Parts)
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It points you to the three connectors behind connecting the DCS to the gen set. Specifically P3 as a member has tried to say check. If power is applied to your DCS and chassis ground (including the ground strap behind the DCS, and the DCS does not respond, you may have a failed DCS. If no power is applied the issue is in RP201 which is a relay panel inside below the DCS where you open the door and it it on the right side on the floor, and these fail all the time due to water intrusion. Battery power from the main DC breaker is applied to this guy and it breakers and fuses power to everything. P5 is suspect and I had pushed back pins in this guy which is a hard one to find, and ours at the training area acted like yours. Let us know what you find. Best to check before spending lots of money.