Mechanics

CHEVY BLOWER MOTOR QUIT

1997 Chevrolet Truck

Air Conditioning problem
1997 Chevy Truck V8 Four Wheel Drive Automatic 200000 miles

Blower motor stopped working (heater-a/c) bought new one (autozone) and replaced. Didnt work. Hooked 12 volt battery charger to old and new b.M. And they worked. Returned new b.M. And purchased blower motor resistor and replaced. Didnt work. Checked voltage 14.00v all settings. Checked voltage from battery charger 12.00v and hooked up directly to b.M. And it worked. Checked ground ok. Whats the problem? Im lost
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Driller753
September 27, 2009.



I'd check the circuits at the high blower relay, go from there. 5.7L engine, not sure of litre size?

JDL
Sep 27, 2009.
I checked the continuity of the high blower relay(h.B.R) from contacts 85 and 86. The connector siide voltage from 87 and 87b to 86.13.5v. Pulled and checked fuse for h.B.R and voltage 12v. Everything good until underhood fuse/relay 50amp blower fuse good but no voltage. A/c relay good. Why am I not getting any voltage across slot? Its a 350 so 5.0 or 5.7 not sure.

Tiny
Driller753
Sep 27, 2009.


http://www.2carpros.com/forum/automotive_pictures/170934_97_chevy_truck_blower_1.jpg



Orange wire is voltage for the coil side of relay, comes from the hvac control module. Black is ground. Purple carries voltage to blower motor. Dark blue is voltage for the lower speeds, comes from resistor. Red is voltage for high speed comes from 50 amp fuse, should be hot all the time. When the relay is not energized there is continuity for the lower speeds. When relay is energized only continuity for high speed.

JDL
Sep 28, 2009.