power supply board

Guys im troubleshooting an oil cooler unit and isolated to the power supply board for the control board.
it has a 10vac circuit going through a signal relay. i have 10vac input but have 7vac on both positive and negative at the output. im wondering if this is caused by the relay if something is going on with the traces on the board. obviously not a plc question but any help would be great thanks

If you have access to the board internals then measure the voltage drop through the fuse and the relay contact.

several things to look at.
loose terminals
bad solder joints at the terminals, i have had that happen, look for bad solder connections/cold solder joints
fuse going bad, replace. yes, they can go bad and still work.
relay contacts are arcing and have gotten pitted, carbon deposits
james