Mechanics

ELECTRIC ACTUATOR ON 93 FRONT AXLE DOES NOT ENGAGE IN 4WD

1993 GMC Sierra • 280,000 miles

I just recently lost 4wd on my 93 Gmc 4x4. I checked it out and adjusted linkage etc, checked wiring for breaks as best I could, found no power to electric actuator on front axle. Checked fuse-ok. The transfer case does engage when I manually select 4wd as the front drive shaft locks in.I am wondering if one of 2 sensors I see on the transfer case transfer power to the front axle when I select 4wd is faulty and how would I check them?
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Vacero
October 9, 2011.



Yes, power comes from a relay. I have attached a wiring schematic for the transfer case. It should help. Let me know if you have questions.