Dodge Repair: 02 ram 1500: multiple electrical problems


Question
QUESTION: Need help! I have a 2002 dodge ram 1500 5.9 slt and my dash has the airbag, abs,p0500, brake light, service 4wd, no speedo or odometer, my heat dont work coarse the buttons for the ac or defrost dont light up so dont work only blows cold in the defrost windshield position.
I have replaced the abs sensor on rear diff, speed sensor on tranny, ignition switch,airbag clock spring, and checked the plugs behind battery looks fine and checked the fuses and relays dont look bad but dont know how to properly check em.
Been tryin to figure it out for the last month or so. An since this has gone down my truck has just randomly shut off while driving 3 times but turns back on an be fine..if you have suggestions anythin is appreciated! Theres no wires pinched or damaged around tranny either.

ANSWER: Hi Cailin,
I need to better understand the situation:
When you say " my dash has the airbag, abs,p0500, brake light, service 4wd, no speedo or odometer, my heat dont work coarse the buttons for the ac or defrost dont light up so dont work only blows cold in the defrost windshield position" would you please re-phrase that so I can understand exactly what warnings are showing on the instrument cluster to be a problem now and also what specific gauges and control knobs are not working. Is the P-0500 still showing up when you do the fault code test is the speedo still not working?
To be sure what are the 'fresh' current fault codes please disconnect the battery and then drive a bit and then check for new fault codes.
Did all the these problems begin together, all at once, or did they come on serially at different times?
When the engine shut off 3 times, were you driving at a steady speed, accelerating, or slowing down?
Perhaps we can see a pattern which will focus out attention on what the causes might be.
Roland  

---------- FOLLOW-UP ----------

QUESTION: My airbag light, brake light, abs light, service 4wd light, check engine light (which is p0500 thats fresh and has always shown that code since this happened).
Came on all at once.
Speedo and odometer is still not working.
For example if i press on the ac button it doesnt engage. My mirror heater doesnt work, vent selector switch doesnt work, tempature selector doesnt work. So right now its only blowing cold air in the windshield defrost postion.
For the truck shutting off 3 times (it was on different trips not in 1 day just randomly done it. 2 times- Its when slowing down when i approach a corner and 1 time when turning off to the side of the road.

Answer
Hi Cailin,
I searched through the wiring diagrams of each of those systems and have found one fuse which is involved in powering 6 of the problem areas, namely a 30 amp fuse in position 3 of main power box in the engine compartment. So begin by checking out that fuse to see if it is blown. Let me know what happens if it is blown and you then replace it.
Thanks for the rating/nomination which you are welcome to do again.
Roland