Well, then the ignition ON-OFF-ON-OFF-ON will display any stored codes on
your odometer.  Some people have trouble with this.  So, first, a couple of
definitions.  'ON' is the position of the ignition switch when the dash
lights come on, and it's one position away from actually starting the engine
(cranking it over).  'OFF' is one position back from 'ON'.

So, the first thing you do, is turn the ignition switch to 'ON'.  Then,
fairly rapidly, you cycle the key back to OFF, then forward to ON, then back
to OFF, then forward once more to 'ON', and leave it there.  This should be
done within 2 seconds or so.

After you finish cycling the ignition, watch your odometer.  If there are no
codes displayed, it will just read 'pDone'.  If there are codes, they will
(usually) be displayed with Pxxxx, where 'xxxx' is a four-digit code.  There
are other letters that are possible besides the 'P', but that's rare.

Write down each of the codes, then find any of the myriad of web sites that
describe the meaning of those codes (I usually just do a Google search for
"OBD-II Pxxxx").

Codes that start with '0' or '1' are standardized (for the most part) across
manufacturers.  Codes that begin with '2' are manufacturer-specific, so keep
that in mind during your searches.  Obviously, the best source of info. on
the meaning of any of the codes is the specific Factory Service Manual for
your year/make/model vehicle.

Now - the above is the standard OBD-II diagnostic codes.  Your truck also
has a separate diagnostic capability for any instrument-cluster-related
problems.  In the 3rd gen Rams, the IC is really the brains behind any of
the systems within the cab...  lights, ABS, locks, windows, etc.  You can
run an instrument cluster diagnostic by holding down the trip reset button
on the cluster, turning the key to ON, and releasing the trip reset button.
The IC will go through several self-tests, then (possible) display one or
more 'C-codes', in the form of "XX nn", where XX is a two-digit alphanumeric
code, and nn is the number of ignition cycles that have occurred since the
problem was noted.

Since I can't find a location online where all of these are listed, here are
the various codes:

01 Airbag warning indicator output circuit shorted. Refer to the appropriate
diagnostic information.
02 Airbag warning indicator output circuit open. Refer to the appropriate
diagnostic information.
03 ABS indicator output circuit shorted. Refer to the appropriate diagnostic
information.
04 ABS indicator output circuit open. Refer to the appropriate diagnostic
information.
05 MIL indicator output circuit shorted. Refer to the appropriate diagnostic
information.
06 MIL indicator output circuit open. Refer to the appropriate diagnostic
information.
07 Wait to start indicator circuit shorted. Refer to the appropriate
diagnostic information.
08 Wait to start indicator circuit open. Refer to the appropriate diagnostic
information.
0B BTSI output circuit shorted or open. Refer to the appropriate diagnostic
information.
22 Headlamp switch input circuit shorted. Refer to the appropriate
diagnostic information.
23 Headlamp switch input circuit open. Refer to the appropriate diagnostic
information.
24 Turn hazard switch input circuit shorted. Refer to the appropriate
diagnostic information.
25 Turn hazard swiitch inpot circuit open. Refer to the appropriate
diagnostic information.
27 Courtesy/dome output circuit shorted or open. Refer to the appropriate
diagnostic information.
28 Glovebox/map lamp output circuit shorted or open. Refer to the
appropriate diagnostic information.
29 Cargo lamp output circuit shorted or open. Refer to the appropriate
diagnostic information.
40 Wiper switch input circuit shorted. Refer to the appropriate diagnostic
information.
41 Wiper switch input circuit open. Refer to the appropriate diagnostic
information.
42 Wash/beam input circuit shorted. Refer to the appropriate diagnostic
information.
60 Passenger door lock switch input circuit shorted. Refer to the
appropriate diagnostic information.
61 Passenger door lock switch input circuit open. Refer to the appropriate
diagnostic information.
62 Passenger door lock switch input circuit stuck. Refer to the appropriate
diagnostic information.
63 Driver door lock switch input circuit shorted. Refer to the appropriate
diagnostic information.
64 Driver door lock switch input circuit open. Refer to the appropriate
diagnostic information.
65 Driver door lock switch input circuit stuck. Refer to the appropriate
diagnostic information.
66 All door lock output circuit shorted to ground or voltage. Refer to the
appropriate diagnostic information.
67 All door unlock output circuit shorted to ground or voltage. Refer to the
appropriate diagnostic information.
68 Driver door unlock output circuit shorted to ground or voltage. Refer to
the appropriate diagnostic information. 6C Driver cylinder lock switch input
circuit shorted. Refer to the appropriate diagnostic information.
6E Driver cylinder lock switch input circuit stuck. Refer to the appropriate
diagnostic information.
80 Incorrect odometer value found. Refer to the appropriate diagnostic
information.
81 Remote radio switch input circuit high. Refer to the appropriate
diagnostic information.
82 Remote radio switch stuck. Refer to the appropriate diagnostic
information.
A0 Internal module FLASH memory checksum failure. Refer to the appropriate
diagnostic information.
A1 Internal module bootloader failure. Refer to the appropriate diagnostic
information.
A3 Battery voltage open. Refer to the appropriate diagnostic information.
A5 TCCM messages not received. Refer to the appropriate diagnostic
information.
A7 VIN checksum error. Refer to the appropriate diagnostic information.
A8 VIN previously stored. Refer to the appropriate diagnostic information.
A9 PCI bus internal failure. Refer to the appropriate diagnostic
information.
AA PCM messages not received. Refer to the appropriate diagnostic
information.
AB TCM messages not received. Refer to the appropriate diagnostic
information.
AC ABS messages not received. Refer to the appropriate diagnostic
information.
AD FCM messages not received. Refer to the appropriate diagnostic
information.
AE ACM messages not received. Refer to the appropriate diagnostic
information.
AF SKIM messages not received. Refer to the appropriate diagnostic
information.
B0 RKE fob batteries low. Refer to the appropriate diagnostic information.
B1 RKE module communication link. Refer to the appropriate diagnostic
information.
00 Done All Diagnostic Trouble Codes (DTC) have been displayed.

Suddenly, without warning, SteveB exclaimed (9/29/2008 2:38 AM):

Why, thank you :)

jmc