Sounds like you're describing the House fuse box. It should have fuses for your furnace, water heater, interior lights, thermostat, water pump, etc.
There should also be a chassis fuse box. You didn't identify what chassis you have, but a front engine Ford or GM, (Workhorse) usually has one under the dash or under the hood. Under the hood it often is in a black plastic box with a lid, containing fuses and relays. Often the turn signal blinker is also there, sound might help track it down.
Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI