Quickly fix a combo of dead dome light, radio, and mirror motors
If you own a second generation Ram truck, you might find yourself in the cross hairs of a mysterious fuse called the “Ignition Off Draw” or IOD. On trucks like the 1998.5 to 2001 Ram 3500 5.9 liter Cummins Turbo Diesel, one tell tale sign you have an IOD fuse issue is that your electric mirrors, radio, and dome lights are all not working. This post covers exploring and troubleshooting issues related to an IOD fuse.
First, the IOD fuse is a 10amp fuse placed in position #12 on the fuse panel that is located on the far left side of dashboard on the interior of the truck. This panel is accessible when you open the driver’s side door. The first oddity you will notice is that this fuse is protected by a “black box” like cover. You will want to start by opening it. Here is how you do that:
Time needed: 5 minutes.
Removal of 2000 Dodge Ram IOD Fuse Cover
- Pull the fuse and black cover out
Use the fuse removal tool to pull back the fuse and the black cover just like you would pull any fuse. It will not come out completely. The black box extends to a little bit beyond the length of the 10am fuse it covers.
- Open the black cover door
The black cover top is held in place by a very small plastic latch that is not visible as it sits on the engine side of the cover. Use the fuse tool to open it from the engine to the drivers seat like opening a door. Grip the top of the black box and rotate it toward the driver’s seat.
- Remove the IOD fuse
Once the black cover door is unlatched, you can remove the 10amp IOD fuse by pulling it toward you with the fuse removal tool.
Once your fuse is removed, inspect it and replace it with a new 10amp fuse. Close the latch on the black cover and push the fuse back into place. You can then turn on your ignition and inspect your electronics in the following order:
- Inspect the dome lights and verify they are working
- Turn on your radio and verify it has power
- Place the mirror adjustment knob to the passenger side mirror and confirm the motor works
- Place the mirror adjustment knob to the driver side mirror and confirm the motor works
If any of the steps above blow the IOD fuse, you will know where the troubleshooting needs to begin.
Pinched Mirror Power Cable
One classic source of an IOD fuse problem is in the electric mirrors. Many second generation RAM owners chose to upgrade their mirrors to more modern ones. When you do this, there is a trick to routing the electric motor cable through a designated channel in the mirror frame. If you fail to do this, when you tighten the mirror it will crimp the power wires into the metal frame of the mirror and cause a short. If after replacing the IOD fuse the mirror motor works for a couple of seconds and re-blows the fuse, you likely have this issue. You can view this YouTube video to see how to route your wires.
One of the desired traits of second generation Ram trucks is that they are simple to troubleshoot, fix, and maintain. One of the exceptions is the IOD fuse. It isn’t documented in the owner’s manual, its black box cover is tricky to open, and the correlation of mirror motors, dome lights, and radio lead the average person to think the problem is much worse than it appears.