At your local auto parts store just ask for the parts book
Can't give you a diagram but the blower speed resistor is under the hood, on the passenger side firewall not far from the blower motor in plain sight.
Blower motor resistors are generally found nearby the blower motor.
Blown fuse, bad fan speed control switch, bad blower motor resistor pack, bad blower motor, or loose or disconnected wiring.
A wiring diagram can be found at this website: http://www.abcccodes.com/95-isuzu-npr-wiring-diagram/ for the Isuzu NPR. The diagram can be downloaded as a PDF file.
3si.org
for the ECM, sorry i left that part out
sounds like a defective blower module
The blower motor is located in the passengers compartment near the right side of the HVAC module...............
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diagram of 95 Chrysler Concorde motor vacum hose
usually on or near the top of the blower motor behind glove box area