RAM 1500 Van V8-5.9L VIN Z LDC (2001)
Ignition Off-Draw (IOD) Fuse: Description and Operation
IOD 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 # 1
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 # 1 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 30 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 30 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. Refer to Battery for the location of additional service information covering the battery.
