I have a 2000 isuzu 5.7 liter box truck. When I turn on the ignition, i don't get any lights on dash, or blower motor. Fuel pump won't kick on.. i have check all the fuses.. any suggestions? Thanks!

Bad connection behind the fuse box

OK several things to check, is there power to the fuel pump, check as close to pump as you can? and did you check the ignition coil?

If you are at or near the 100,000 mile mark then your fuel pump may have failed. If you remove the fuel filler cap and listen carefully at the filler neck while someone turns the ignition key to "run" [don't actually crank the engine] you should be able to hear the fuel pump buzz for about a second and a half as the key is turned On. If you don't hear the pump buzz then odds are your pump is dead. Your pump may have actually failed making it appear as though you ran out of fuel. Not to uncommon. Hope this helps and good luck!

That sounds like a bad blower motor to me. Try this: Remove the lower panel from under the right side of the dash. Turn your blower motor on HIGH. Look up under the dash behind the glove box and find your blower motor housing. Take your fist and "thump" on the blower motor housing. If the blower starts blowing, replace your blower motor.

If the engine turns over it is not likely an ignition switch. Can you hear the fuel pump kick on? Is there spark at the distributor cap? My thought leans towards either a bum fuel pump or ignition amplifier (ignition module). If you would like a manual to aid in testing, let me know.

do you mean the truck won`t start and run or do you mean it won`t turn over with the key.if it won`t turn over with the key the you may have a starter problem.if you mean won`t start then it could be the fuel pump not working.with someone cranking the motor you should hear the fuel pump running with the gas cap off and listening at the filler neck.or hear it running listening under the truck at the gas tank.if you don`t hear it then you can hit the tack sharply with your hand or a rubber hammer,it hear the pump start to run then the fuel pump needs replacing.if not check the fuses under the dash and under the hood.if they are good then it may be the pump relay in the relay box under the hood and it should be marked on the box or lid.

Hope this helps your out. I know the diagram and locator is a bit blurry but hopefully it gets what you need.
Drivers kick panel:
Front wiper 20A - Front wiper system Cigar 15A- Cigarette lighter Audio 10A- Audio, remote control mirror Air Bag 10A -Air bag diagnostics Stop lights- 15A -Rear brake light, high mounted stop light ECU B+ 10A - Shift lock actuator, transaxle controle module, radio, engine control module Room 10A - Interior light, clock, ignition key reminder, rear cargo area light switch ABS 10A- Anti lock brake system control unit ECU IG1 10A - Transaxle control module, shift lock actuator, ABS control unit, DRL unit Meter 10A - Instrument panel, back-up switch, electronics time control module, inhibit switch Turn signal 10A- Hazard switch ,front and rear turn lights, turn indicator IGN1 20A - Ignition switch ABS 30A- ABS pump motor TNS 30A- Tail light, license plate light COOL/FAN 30A- Cooling fan Cond/Fan 20A- A/C condenser fan Starter 15A- Start signal , Fuel pump Blower 25A- Blower Motor SR/ACC 10A - Ignition switch Hazard 15A - Hazard and turn signal light D/Lock 25A- Door locks ABS 30A - Anti lock brake system control P/W RH 20A- Power window motor right hand P/W LH 20A- Power window motor left hand IGN2 25A- Ignition Switch
Engine compartment :
Head 25A- headlights IG 2 30A- Ignition switch IG coil 15A -Ignition coil, condenser,generator IC regulator, diagnostic connector. O2 down 10A- Rear O2 sensor O2 up 10A- Front O2 sensor Fuel pump 10A -Fuel pump unit Injector 10A -Fuel injector ,camshaft positioning sensor, purge solenoid valve, EVAP, IAC actuator, Mass Airflow sensor, EGR stepper motor. fuel pump relay coil, vehicle speed sensor. A/Con 10A - A/C compressor controls, cooling fan BTN 30A- Brake light , high mounted stop light. Tail light LH 10A- License plate light, tail light , rear combo light, instrument panel illumination Tail light RH 10A-License plate light, tail light , rear combo light, instrument panel illumination Head low 15A- Headlight Head Hi 15A-Headlight Horn 15A- Horn

Inside kick panel

first turn the ignition on but not all the way to start it. listen to see if you hear a whining noise. your trying to listen for your fuel pump. if you dont hear it then open the hood and locate your fuse box. inside the box there will be a label remember your looking for the fuel pump fuse. when you found the fuse pull it out and hold it to the light. inside the fuse you can see the contact. look to see if its one piece or you can see a burned spot on the fuse. start there then well move on to the next thing

the ignition switches are typical to fail

Click on link & scroll down to figure 5 & 6 . Click on picture for expanded view.

http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c1528007cb56