Codes 920, 921 and 999, No Bus?

Hi,

I'm not familiar with the tool you are using, but I assume green means there is a completed circuit. So, when you check, is the fuse removed and are you probing both sides (one at a time) of the connector in the box? Is the ignition key in the on position?

I ask because with the key on, there should already be power to the fuse, at least one side. The fuse bridges the power to the next other side of the fuse in the box to transfer power.

Let me know that and also, I am showing four possible engine code numbers for the 5.9L. Three of the four are diesel and one is a gas engine. I need to know what the 8th digit is in the VIN number on your truck so I can make sure to be reviewing the correct wiring schematics. See pic below.

Also, please confirm the codes you have. Are they P codes?

Let me know.

Take care,

Joe

See pic below.

Hi,

The idea that your DMM indicates green, does that mean it's completed the circuit? Also, there should be power at the fuse. You shouldn't need to go from the battery positive. If you test between the fuse and the battery ground, what do you find?

If you remove the fuse, test the battery negative to one side of the fuse holder at a time. One side should have power and the other won't with the fuse removed.

Also, if possible, scan the computer with a scan tool to get P codes.

Let me know.

Joe

Hi,

The fuse should have power at all times. There is a splice in the power supply near the power brake booster.

The power supply to that fuse comes direct from the battery. The only thing between the battery and the fuse is a wire splice. See pic below.

I need you to locate the red wire for that fuse and check if power is present at the wire. If there isn't, trace it back to the splice and check for power there.

Let me know what you find. Also, I am looking at the schematic for a Ram 1500 Van. Let me know if that isn't correct.

Take care,

Joe

See pics below.

Hi,

Don, I looked up the 3500 and it has the same schematic. That tells me there is an open in the power supply to the fuse or the fuse box is bad.

It is only a theory, but I suspect the problem is going to be at the wire splice I mentioned. Are you comfortable locating and checking it?

Let me know.

Joe

Hi,

I dug into it a little deeper. It is splice 111. It can be in one of two places based on if the vehicle has a factory trailer tow package or not.

See pics below and let me know if it helps.

Take care,

joe

See pics below.