2021 f550 4x4 not working

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Nov 15, 2022 | 05:46 PM

sswanner

Thread Starter

2nd Gear

Joined: Nov 2022

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2021 f550 4x4 not working

Truck has been sitting since last week of August. Went to use 4x4 yesterday and right away it says check 4x4. Locked hubs in manually, but no change 4x4 not engaging. Checked all fuses related to 4x4. Vacuum lines seem ok, figured if it was a vacuum issue manually locking the hubs would engage 4x4 but not certain. Found no dtc’s.

has anyone experienced this issue before?

Nov 15, 2022 | 06:06 PM

406f150

Laughing Gas

Joined: Jul 2017

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Have you verified the shift motor on the transfer case is working and shifting it? A varmint may have chewed the wires off to it.

Nov 15, 2022 | 06:12 PM

sswanner

Thread Starter

2nd Gear

Joined: Nov 2022

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Yes, I checked wiring over under there and even unplugged and plugged back in. All looks ok.

Nov 15, 2022 | 06:36 PM

DSLTRK60

Fleet Mechanic

Joined: Apr 2015

Posts: 1,641

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From: Phelan CA

Quote:

Originally Posted by sswanner

Yes, I checked wiring over under there and even unplugged and plugged back in. All looks ok.

Put a meter on the transfer case connector to see if voltage is present when 4x4 is engaged. You will have to find the color wire for the 4x4 high command input into the motor via a service manual.