Sounds like either a bad battery or maybe charging system problem.
When the battery is close to dead or at least low enough on the power scale not to start the truck there is a point where the battery has enough power to energize the relays with the key on but not enough to keep them on and everything else reacts making you think there is a problem with the lighting or the dash lighting.
Get the battery charged and check things out, then if it is still happening Buggman’s approach is a good one to get started, grounding is one of the most missed diagnosed problem in a vehicle’s electrical system.
Remember the engine portion of the electrical system can draw 14.8 volts to run at its peak, anything less will cause poor starting, poor running, and poor gas milage.
Also, thinking... have the battery load tested and also the alternator to make sure it can handle the charging task. Some Shops can actually tell you if there is just leakage current causing you problems or not.
If there is a leakage problem, you will need to trace down the component causing it and fix it or put a switch in line to shut off the component when you leave the vehicle for a long time.
Another thing to consider is if the starter is weak and the connections are poor, this too can be a major problem when starting. To start a vehicle the battery has to put out all of the amperage it has in reserve, very high amperage and far more than most people thing it can even put out. This type of draw and poor connections will drain a battery almost instantly and appear to have been a bad battery.
4x4, 5sp, Std Cab, Stepside, E4 Red
4” Lift - Coil-Overs, 6” SkyJacker Leafs - No Blocks (Mistake)
31 Spline FX4 Rear Axle, 4.56s and OX Locker, Hurst Shifter w/Optional Stick and "Made by Grev" alignment adapter
Last edited by Scrambler82; 07-23-2013 at 06:57 AM.