I changed the battery, and the van staarted just fine. I put it in drive and te instrument panel went dead (even the turn signals. Any idea what this could be?

then starter motor is dead, and is silent, and will not crank the engine at all(I GUESS)
correct?
starter dead is just 6 causes posted her 1000 times and 1million times if you googled why is my starter dead
again just for your causes.
yous said jump starts fail but no words at all is the starter motor dead silent.
I can push start my car but it has a manual transmission.
all IP cluster freeze when engine dies and goes to self test mode , glows lamps.
scan the PCM now and it tells you what failed with DTC error as you crank any dead engine.

causes
battery cables lugs loose or rusty cleanm em.
1:battery is bad, charger it up first or replace it if charging fails or load test fails (those are TOOLS)
2: fuse blown. to IGN switch (check all fuses if savvy)
3: IMMO lamp not unhappy, bad key, lost 2nd spare key? oops. but cuts spark and confuses many.
4: keyswitch bad ST pin failing and BAD.
5: PRNDL switch bad (a/t box) shift tO N=neutral and turn key to ST crank position, cured?
6: starter relay bad.
7: starter motor dead and bad.
8: all wires connecting all this up above bad (we use a volt meter) to find all these.

THE STARTER MOTOR CAN BE HOT-WIRED TESTED IN-SITU, AND TESTED KEYS IN POCKET SAFE.
POSTED VAST TIMES THIS) OR ASK HOW. OR GET THE CAR SERVICED, BY FOLKS THAT KNOW HOW.
SKILLS AND TOOLS BOTH. YOU DO NOT HAVE.

TURNS OVER(EEKS)
50% OF POSTERS MEANS STARTER IS DEAD."NOT TURN OVER"
50% OF POSTERS USE THE WORD FOR ENGINE RUNS OR NOT. (CRAZY NO?) THIS USELESS PHRASE?
BEST IS SAY CRANK AND AVOID THE SILLY WORDS TURNS OVER.

CRANKS AND WILL NOT START (50 CAUSES)
OR WILL NOT CRANK (SURE IT CANT START)AND 6 CAUSES, BUT MINE PUSH STARTS ANY DAY.

IF THE STARTER MOTOR IS SILENT SAY SO
OR SAY IT CLICKS ONLY OR CHATTERS ONLY.
THE DEAF HELPERS CAN NOT HEAR YOUR STARTER , EVER. UNLESS VIDEO OF IT POSTED WOW..

It sounds like an alternator related issue. Once the battery drops below 12 volts it will do lots of silly things with gauges and thats why when you change it all works fine. Check that with engine running with a volt meter you have 13.8 to 14.2 volts across the battery, if not you may have an alternator issue

Well, the fuse(s) or relay(s) exist SOMEWHERE in the vehicle. If you don't have an owner's manual, search online for "location of fuses for xx year, model."

More then like it's the instrument cluster . .Plus you probably have no idea of how complex these are . Has microprocessor inside with logic programmed in . Taking it to a qualified repair shop an having it diagnosed would be your best bet . Hooking up factory scan tool to see if the instrument cluster will communicate with the tool , an checking for DTC'S - diagnostic trouble code's .Messing with thing's you have no clue about will only make it worst . YES , changing the PCM would need to be programmed ,dealer only .

Check your alternator. My van did something similar. I was driving down the road and all of the sudden my windows, a/c, radio, door locks, speedometer, everything electrical went down. We stopped and tried to crank it and it wouldn't. Then finally it cranked up went another mile before the fuel pump quit working too. It was the alternator. I had to have someone come jump me off and follow me to the parts store and then home for it to be fixed.

Checked Every fuse in the fuse box (no small task).This includes #4 - Power point Instrument Panel, #14 - Day time running lamps (auto lamps doesn't work nor does auto lock), #27 - ignition switch run feed, #35 - Instrument Cluster, #41 - Instrument Cluster, #42 - Delayed Accessory, #45 - Ignition switch run/start feed, #102 - Door locks body security module, #103 - Ignition switch, #110 - Ignition switch, & #116 - Ignition switch. But I also check all other ones as well, they all register OK. AC panel & radio work. Turn signals work. Mileage does not work, trip computer does. So, basically, everything works except auto head-lights, auto locks, and the dash cluster (no MPH, RPM, mileage display, Fuel, Temp, Tran Temp, and Oil Pressure).

It seems that the bulbs went out or the ribbon cable that runs behind the instrument panel burned out check on a junkyard for a replacement instrument panel and replace it, verify that the truck you pull out the instrument cluster is the same year and the same model.

Sounds like PCM fault. You need to get the truck scanned by a professional. what area are you located?
I run TMC auto (314) 537-1814

alternator.
the vehicle was running off the battery.
if the battery was bad,the truck would run fine off the alternator.
get an avr test done/

You better have the alterntor checked, you said the battery was putting out 12v. was that with the car running or off? If it was running, it should have pushing between 14 and 15 volts, if it wasn't with it running, replace alternator.