Need Help!
 

OK so I've been having this problem for a while now it comes and goes but I'm finally getting fed up with it. When the truck is cold and I first go start it up the lights will dim then brighten and repeat this until it warms up to where it will stop. The voltage also jumps up and down on the gauge it will fluctuate from about 11volts when the lights are dim to 13 volts when the light are bright. I also have problems with the overdrive not working sometimes. The speedo will drop to zero and stop working and the voltage gauge drops down to 11 volts. Then when it kicks back in the wait to start light will flash and then it will start working again.

No personal experience with Dodges but there a many articles on the regulator on these and their problems
First point would be to go through all the connections and that includes all ground points. Pull them apart and clean all contact surfaces.
Alternator to battery, battery to main supply/fuse box.

As a temporary measure, you can disable the grid heater (if your climate allows). Its the pair of ring terminals of about #12 wire coming off the battery lug.

U2slow is right about the grid heaters doing all this, as they cycle they draw all the voltage out of the system. During this time the ECM may experience low voltage and shut off then restart causing the wait to start light and speedo to come back on.
Its normal to see the fluctuation in cold weather.... but it should not be excessive 11 volts is too low. load check both batteries and have your alternator checked. My bet is you have a weak battery or bad ground etc.

K I'll try the grid heater before it gets to cold. I know its not the batteries because I just put in 2 new ones last winter.

Any updates?

Out of curiosity have you load tested the batteries?

With the cold starts I can tell you my second gen does the same thing. It's just the grid heater running through its cycles. If it's dropping your voltage that much though you may have a battery or alternator issue.