i have a 00 express 4.3 liter it cranks but will not run, i can hear the fuel pump run when the ignition is turned on that seems ok.But also the blower motor stays running constantly with the ignition turned off. Any help would be appreciated.

also when i connect a scanner for a code it says no communication

Check all the fuses, got spark, fuel pressure, will starting fluid sprayed in the intake kick it over, all basic diagnostic steps. Any work done prior to this, did it die while driving, or just not start, lots of info missing as you can see.

fuses all good, ill check for spark and pressure, i didnt know if it was a common electrical problem with these vans

Also your security light isn't coming showing a problem with a key switch.