I'm also pulling a P0237 code, but with all the other electrical funnies going on, I doubt the MAP sensor is actually bad.
This truck was running fine, then it got a 'Water in fuel" light. Shortly thereafter, the oil pressure gauge started dropping to zero, then coming back up. Check gauges came on as the oil pressure went stupid.
This happened once before, on trip my wife was taking. I ended up driving out in my '01 and reseating every connector under the hood I could find and reach, several times.
So far, I've cleaned the battery terminals, reseated all the bulkhead connectors, and every other connector I could reach. I cleared the codes using my reader, but the 'Water in Fuel' comes on as soon as I start the truck. (there is NO water in the fuel). This time, the problem doesn't seem to want to go away. Any ideas?
Oh, and one thing I HAVEN'T done, but should have, is check all the relays and fuses.

 

you need to check the wif sensor which is on the fuel filter. probably needs to be replaced.
"the WIF sensor is located on the side of the fuel filter housing" from my manual......

 

I'll check that tomorrow evening (can't do it tonight, working).
In the first post, I was unclear. ALL of the symptoms (CEL, Oil pressure zeroing, Check Gauges, etc.) return withing a few minutes of engine start, but the WIF shows up immediately.

 

Dodge didn't make this an easy troubleshoot. It could have been, but the FSM wiring section is less 'technician friendly' than I expected. No actual 'schematics'. Lots of pages to scan to put togeher a reasonably accurate picture. The K104 circuit was common to all the sensor errors I was getting. It turns out that I spent one heck of a lot of time trying to figure out why my K104 circuit (which is shown in the '99 FSM as 'B+' [+12vdc]) didn't have any 'B+' sort of voltage. I tracked it back to pin 11 of the ECM, where there was also NO B+. Hmmm. On a whim, I looked up some wiring diagrams elsehwere on the WWW, where, low and behold, the same circuit is shown as 'Sensor Ground'. That checked out with a meter, and I quickly found where the wires for the WIF had chafed together, shorting. The big clue was that I still had a WIF indication when the sensor was disconnected.
In case anybody cares: the WIF sensor has no active components. It's basically to wires sticking into the filter canister. Diesel fuel is a pretty good insulator, and water isn't. Aside from leaking, I don't think this particular sensor can go bad.
Anyhow, the '99 is back on the road despite less than perfect tech data.

 

Grider

As long as you did a less than perfect job of the repair, to go along with the less than perfect technical info.... its ALL good.

I frequently get to read service manuals for japanese machines, that have been translated into about 12 other languages, including swahili, before being translated to engrish. As it stands, I have a whole new appreciation for what common items can be called, as opposed to what they do.

Good job on finding the WIF wiring. Jobs like that can be a widowmaker.

 

I have to admit to being spoiled. The Tech Orders I've used for the last 30+ years working on electronics (USAF stuff) have been excellent, and highly standardized. That said, the FSM for the '99 is really good, with the exception of the wiring diagrams (or lack thereof).