RAM 2500 Van V8-5.2L Prop VIN 2 (2000)
Ignition Off-Draw (IOD) Fuse: Description and Operation
Ignition-Off Draw Fuse
All vehicles are equipped with an Ignition-Off Draw (IOD) fuse that is removed from its cavity within the relay and fuse block when the vehicle is
shipped from the factory. Dealer personnel are to remove the IOD fuse from the storage location and install it into relay and fuse block cavity 4 as part of
the preparation procedures performed just prior to new vehicle delivery.
The driver side instrument panel end cap also serves as a snap-fit fuse access panel that can be removed to provide service access to the fuses in the relay
and fuse block. A finger recess is molded into the end cap for easy removal. A fuse layout map is molded onto the instrument panel side of the end cap to
ensure proper fuse identification. The IOD fuse is a 15 ampere mini blade-type fuse and, when removed, it is stored in an empty fuse holder molded into
the instrument panel side of the end cap.
The term ignition-off draw identifies a normal condition where power is being drained from the battery with the ignition switch in the OFF position. The
IOD fuse feeds the memory and sleep mode functions for some of the electronic modules in the vehicle as well as various other accessories that require
battery current when the ignition switch is in the OFF position, including the clock. The only reason the IOD fuse is disconnected is to reduce the normal
IOD of the vehicle electrical system during new vehicle transportation and pre-delivery storage to reduce battery depletion, while still allowing vehicle
operation so that the vehicle can be loaded, unloaded and moved as needed by both vehicle transportation company and dealer personnel.
The IOD fuse is removed from relay and fuse block fuse cavity 4 when the vehicle is shipped from the assembly plant. Dealer personnel must install the
IOD fuse when the vehicle is being prepared for delivery in order to restore full electrical system operation. Once the vehicle is prepared for delivery, the
IOD function of this fuse becomes transparent and the fuse that has been assigned the IOD designation becomes only another Fused B(+) circuit fuse.
The IOD fuse serves no useful purpose to the dealer technician in the service or diagnosis of any vehicle system or condition, other than the same
purpose as that of any other standard circuit protection device.
The IOD fuse can be used by the vehicle owner as a convenient means of reducing battery depletion when a vehicle is to be stored for periods not to
exceed about thirty days. However, it must be remembered that disconnecting the IOD fuse will not eliminate IOD, but only reduce this normal
condition. If a vehicle will be stored for more than about thirty days, the battery negative cable should be disconnected to eliminate normal IOD; and, the
battery should be tested and recharged at regular intervals during the vehicle storage period to prevent the battery from becoming discharged or
damaged.
