New to 4WD maintenance. 4WD light turns off, but stays engaged, 2005 Ranger.

[Sternwheeler]

To be clear - I engage 4H, and the truck seems to remain in 4H, but the 4WD light turns off a moment after engaging. Is there a sensor that "reports" when the transfer case has completed its shift? If so, perhaps that is my problem?

Thanks everyone. Just got this truck and with only a few minor issues. I can handle the rest, but this stuff is not in my wheelhouse (yet).

Sternwheeler

 

[RonD]

Welcome to the forum

Not really a sensor, its a contact wheel with 6 "arms"/contacts

Shift motor seen here, disassembled: https://www.explorerforum.com/forums/index.php?threads/how-to-rebuild-4x4-shift-motor.123542/

When you select 4H on the dash switch the 4x4 Module(behind radio in 2005) looks at the contact wheel to see "where" the shift motor/transfer case is now, 2WD or 4L
If 2WD then 4x4 module powers shift motor to turn counter clockwise until Contact wheel shows 4H contact

It THEN turns on the 4H light, dash switch doesn't turn on the light, contact wheel in correct position does, so there should always be a delay between selection and light coming on, or going off, shift motor has to move into position first

Contact wheel seen in picture 5, "arms" in picture 6, the "arms" are adjustable, meaning you can turn the top part with the, arms attached, so it lines up better with contact wheel in it 3 positions, 2H, 4H and 4L


FYI, if 4WD lights Flash it means 4x4 Module has activated shift motor but Contacts are not changing, so it stops the voltage and flashes the lights
This is often a blown shift motor fuse in the engine fuse box

 

[Sternwheeler]

Thank you so much! This looks very helpful. I’m bookmarking this.

 

[adsm08]

It is also possible for the transfer case to get bound and appear to have completed the shift, but still be partially in 4x4. That is usually caused by stress binding parts inside the case. Stopping, putting the trans in neutral, and then backing up a few feet after shifting back to 2wd will usually take the stress off and allow the pieces to finish moving.

 

[Rangerx2]

This is what seems to occur with my F-150 when I take it out of 4wd. I apply the same aforementioned trick and it comes back in to 2wd just fine and all the components stay happy. If I don't do this the truck stays in 4wd when it doesn't need to be; then T-case, front axle, and front hubs start getting angry with me. This 2012 F-150 I have now is the first 4x4 I've owned so I asked a lot of dumb rookie questions too.