91 wiring diagram

Does the A/C compressor engage ? Does the heater work ? Possible A/C compressor clutch if not turning on or A/C compressor clutch relay . Viewing a wiring diagram an testing the electrical circuits would be the way to find the problem .
The Trainer 40 When the compressor won compress

http://www.bbbind.com/free-tsb

either the fuses are blown or a relay is not working right..

you might want to recharge your air compresser or the heater coar thats my guess it worked on my truck

Main fuse panel is under the dash, drivers side.

The order is
ENGINE / STOP / POWER WINDOWS
\\\\\\\\\\\\\\\ / METER / HAZARD
HTD BLIGHT / CIGAR / TAIL
ROOM / DOOR LOCKS / AUDIO
\\\\\\\\\\\\\\\\\ / FOG LAMPS / AIR COND
\\\\\\\\\\\\\\\\\ / COOLING FAN / WIPER

If the fuse is good, it could be the fan relay is bad. It's in the engine compartment, behind the left headlight assembly, the connector to it has 4 wires, yellow, yellow & green stripe, black, green with red stripe.

Or a bad fan...not usually...good luck...

Yes if you go to the dealer they usually have no problem printing out the diagram you need.

here is a diagram, if u can't see it go to the link below.
http://autorepair.about.com/library/firing_orders/bl-fo-9225.htm

IT IS LOCATED IN THE POWER DISTRIBUTION BOX UNDER THE HOOD, IT SHOULD BE MARKED IT IS A 60 AMP MAXI FUSE.

6
Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 86-98 97-98 85-91 93-97 95-98 85-98 ECT Sensor (Engine Coolant Temperature)
defective circuit or unplugged / defective sensor
10
Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 86-98 97-98 85-91 93-97 95-98 85-98 IAT Sensor (Intake Air Temperature)
defective circuit or unplugged / defective sensor
16
Accord Civic CRV CRX Del Sol Odyssey Prelude
90-95 88-95 n/a 88-91 93-95 95 88-95 Fuel Injector System
defective circuit or unplugged / defective fuel injector

check your wiring for dirty connections or broken wires, you may have wires that are rubbed through or connectors that are not making full contact. you will need an ohm meter and check wires for continuity. a wiring diagram will be needed.

as long as it is the same motor you can change everything.

Any chain auto parts store will have aftermarket manuals from Haynes and/or Chilton for your Blazer and they are a good investment at <$20 US.
They contain all the information a shade-tree mechanic needs.