Alternator Fuse Link in PDC (power distribution center)

[Iron Duke II]

I'm scratching my head for what caused a blown fuse link Fuse Link #12 in PDC (power distribution center). No work performed near the alternator lately, nothing is loose. Not sure if it is 120 or 140 amp. Will look for a new one in the morning. Maybe this one. https://www.oreillyauto.com/detail/...uck-1996-dodge-ram-2500?q=120+amp+fuses&pos=3

 

[SAndreasen]

Have you done anything with the batteries or battery cables ? I shorted mine out and popped it the other day changing a steering shaft

 

[Iron Duke II]

I took the cables off myself three weeks ago to clean the terminals.

I did take the truck into my local family run repair shop to replace the heater core, replace the ac evaporator, move the boost/egt/trans gauges to the A pillar, and replace dash top. The shop had it for two weeks. When I went to pick it up yesterday, I did the walk-around, popped the hood, got in and started it. Noticed the dash voltage gauge only registered about 12 volts at idle and with any amount of throttle applied. I took it for short test drive and only got about 5 blocks away before the GEN light came on. When I returned to the shop I had the mechanic that did the work check the charging system and scan the pcm. He said it looked to be the alternator. Went into the shop owner and said I would take it home and check the alternator further and would be back, I found an issue they may have inadvertently caused. I had spare tested alternator on hand, so I swapped it out at home (4 miles away) last night. Put in the the spare alternator, same low voltage issue. I had completely forgotten about the 120 amp fuse in the PDC, should have checked it first. Anyway, I have since noticed the egt gauge is acting erratic and the brake controller not showing power. I'm thinking a loose ground or ground fault from behind the dash or A pillar install. Going to parts sore to see if they have the fuse this morning.

Probably should have tried to tackle this work myself.

 

[petersonj]

Probably should have tried to tackle this work myself.

At least when you tackle it yourself, you know what you are getting.

I am not sure how a '96 is wired, but the 24v second generation has a 140 amp fuse in the same location in the fuse panel. It is the heavy charge wire directly from the alternator that connects to it. The fuse is there not to protect the alternator, but to stop the current flow from the batteries should a short circuit to ground occur between the alternator and the batteries.

It is my guess that whoever was working on your truck while in the shop shorted that circuit unintentionally and the fuse blew. No one was aware the fuse had blown.

If your alternator is wired in this fashion, then neither alternator will work until the fuse is in place. The original alternator is probably fine.

- John

 

[Iron Duke II]

O'Reilly Auto Parts had the 120 amp fuse. The alternator/charging system is operational now. Still have to check out the egt gauge and brake controller.

 

[BigPapa]

I popped that fuse on mine while replacing the thermostat. I didn't disconnect the batteries and a wrench touched the wire on the back of the alternator. I heard it pop.

What brand and type are the gauges? I had Auto Meter and my pyrometer would take spells of the needle flipping around everywhere. Auto Meter said to run a ground from the gauge to the block.

My brake controller, a Takonsha, doesn't show anything unless there is a trailer hooked up. Also, there are PAL fuses in the PDC for the trailer brakes.

 

[Iron Duke II]

They are Banks gauges that the previous owner had installed on top of the dash in the late 90's. The pyrometer that was relocated to the A pillar is now not registering temp until the ignition is turn off. It flips up upon ignition and immediately falls to zero will the truck is running. To clarify, when the engine is running the gauge reads 0, and when I shut it off it reads 300 degrees.

My brake controller light has always been on will the truck ignition switch was engaged. Not now.