I recently had Dead pedal problems. Also Wait to Start (wts) light is not coming on. Now I have no lift pump noise before starting truck. Or after bumping the starter. 

I changed the APPS and that fixed the dead pedal only.

Now I tried hooking up programmer to check codes and the programmer won't load up with key on. After 20 seconds or so the odometer says NO BUS.

 

So I'm 95% sure the ECM is shot. I bought a used ECM. Auto trans, same year. I have called 6 dealers, NOBODY has DRBIII software anymore to reprogram it to my vin. The software has all been updated to some new carp.

 

So. Will my truck run and drive if I just swap ECM's? I've read conflicting stories. A lot of them say Yes just swap it.

If it was me I'd swap it and see what happens but you need to figure out what fried the other is ecm. More than likely excessive AC noise from the alternator, if your truck can still start and run on the current setup I would make sure the alternator is in good shape before hooking up different ECM. If your lift pump is not coming on you may have to temporarily hot wire it so you don't fry your VP.

And just in case wait for more responses

If same year and trans. it should be plug and play. If not contact https://smartyresource.com/. Do what @Dieselfuturesays though and figure out what caused the failure first.

The truck does still run and drive. I'm definitely going to test the AC voltage noise before I swap ECMs. And I do have a smarty if that can help.

Read the bottom of page 2 and into page 3 to see what @BrianAtSmarty had to say. He's a vendor and very willing to help, unlike a dealer without a DRB111. I think they have the tool, just nobody who knows or remembers how to use it.