I have 1995 dodge Dakota code 21 - 1995 Dodge Dakota

SOURCE: engine diagnostic codes

12..Battery was disconnected within the last 50 key-on cycles (Resets after 50)

They dont list the others may want to recount the flashes..

SOURCE: engine diagnostic codes

I don't have a dodge ram but the codes for the dodge vehicles where pretty much the same. For my intrepid the codes read for the following numbers

12 - Problem with battery connection (This usually happens if you disconnect the battery)
21 - Problem with the oxygen sensor circuit
52 - Oxygen Sensor signal input indicates rich mixture during engine operation.

It sounds like you may need to change an oxygen sensor. Hope this helps.

SOURCE: brake problem with a 1995 dodge dakota

have you checked the power booster and the master cylinder> what about the wheel cylinders> have you looked at them to see if theres a leak somewhere?

SOURCE: Fuse placement for the cigarette lighter in a 1995 Dodge Dakota

Fuse #7 15 Amp LT Blue

SOURCE: 1995 dodge dakota computer error code 12,back up

This code only means that you have disconnected the power to the PCM.
This code will stay until 50 key turns have been completed from the last time you disconnected the battery.
Your check engine light should not be on if this is your only code.
If this helps and one give some feed back
Hope this helped FixYa.