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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: jpatters13 on July 22, 2018, 11:33:15 am

Title: 1974 non-A/C C10 heater blower wiring
Post by: jpatters13 on July 22, 2018, 11:33:15 am

I am rebuilding a 1974 non-A/C C10.  I have a new 3-speed heater/vent control and a new blower motor and resistor.  See pics.  I replaced all of the wiring with an updated harness and accidentally threw out the connections to these items. Soooo, I just need to know which terminals get connected bwtween the blower motor, resistor and control.  Any help would be appreciated.

Title: Re: 1974 non-A/C C10 heater blower wiring
Post by: bd on July 22, 2018, 01:16:47 pm

1974 Factory Wiring Manual (http://www.73-87chevytrucks.com/techinfo/7387CKMans//Wiring/ST_352_74_1974_GM_Light_Truck_Wiring_CK_G_10_30_Only.pdf#page=2)

Also, plug the unused external vent hole in the motor housing.

Title: Re: 1974 non-A/C C10 heater blower wiring
Post by: jpatters13 on July 22, 2018, 05:03:22 pm

Thanks. Do you know which terminals on the fan switch get connected to which connectors on the resistor, though? The diagrams show three wires to each but not which ones get plugged to which prong.

Title: Re: 1974 non-A/C C10 heater blower wiring
Post by: bd on July 22, 2018, 10:11:05 pm

Look at the wire colors in the schematic.