I have a 95 that I am trying to resurrect. 12v with P7100, as you all know. My heater grid wasn't working, and I went looking for a fuse.
I went into the power center under the hood and found some odd things, but no heater grid fuse.
I realized that the PCM controlled the "wait to start" light and grid, and I put a PCM in and now it works. (I had removed the PCM for Dad's truck and my replacement junkyard PCM has not arrived yet)
I still have questions about odd stuff I noticed in the power center though.

Among the odd things, per the label under the cover:
30 amp engine control fuse
20 amp fuel pump fuse
fuel pump relay
auto shutdown relay
Since my 12v does not use any of these, I wonder why these sockets have fuses and relays in them. Are they just unused and Dodge had extra fuses and relays so they decided to put them in there?

Answers to any of these questions will be appreciated.

Thanks,
Chris

 

The grids run off a fusible link wire that comes straight off the battery positive.
Often battery corrosion will eat the wire causing problems.
Other common problem is the two small wires on the grid relays almost under the battery come loose. They are just pushed on to studs, squeezing them a little tighter with pliers and reinstalling fixes the problem.

More than you ever wanted to know> Ram Diesel Manifold Heater Problems

 

I realized my missing PCM was the problem and have amended my post.

Thanks,
Chris

 

Not sure about the fuel pump relay or fuse, but your truck does use the ASD relay, PCM brings it in to control other functions, without it your truck doesn't know it is running ( cruise, AC, charge, etc.)

If i get a chance later, i will pop the hood and look at mine.