Good morning, this vehicle broke down because the diesel electric pump inside the tank no longer worked (seized). The fuel tank was also cleaned. After 10 days, the customer has broken down again. We found that the correct 12-volt power supply is not arriving in the diesel pump connector, but varies from 11 to 10 volts and you can hear when it faults that the pump is suffering. It returns to its normal noise when the correct voltage arrives. We have already replaced the starter battery because it was no longer holding a charge and also the pump control relay, but nothing. I wanted to know if there is any part a connection that could possibly be overheated to check.
Thank you.