4WD LIGHT FLASHING!!

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Joined
Apr 9, 2026
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1
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Location
Ontario, Canada
Hey guys, need some advice. My 4WD was working perfectly up until yesterday, engaged quick, no issues at all. I parked the truck last night with 4WD on, and this morning when I tried to switch it back, the 4WD light just keeps flashing.
I’ve tried messing with the lever and the switch, driving it around, neutral, etc., no luck. The only time the flashing stops is when I press the 4WD switch to change modes, it’ll stop for like 2 seconds, then starts flashing again.
Truck drives totally normal otherwise. Anyone run into this before or know what usually causes it? i dont know but I’m guessing the actuator’s seized. Do we have to take the whole transfer case apart to fix it, or can we just pull the actuator and swap in a new one?
 
Year and model would be helpful for giving advice on how to troubleshoot
 
Had a similar issue on an 80 series a couple years back. The flashing 4WD light usually points to the actuator motor on the front differential, not the transfer case. Check the vacuum line to the actuator first — they crack with age. If vacuum is fine, test actuator directly with 12V. Also inspect the rubber boot on the actuator for moisture damage.
 
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