2012 E350 - Fuel filler door won't lock shut

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Mar 14, 2023 | 12:42 PM

gunbunny

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2012 E350

2012 E350 - Fuel filler door won't lock shut

Wife refilled the gas in her E350, then when she went to close the fuel filler door, it wouldn't lock shut. Some further investigation seems to indicate that the switch that activates the lock solenoid has failed. Did some searching but can't find the part number or any directions on how to replace it.

Can anyone point me in the right direction?

Mar 14, 2023 | 02:57 PM

konigstiger

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From: North Scottsdale, AZ

'71 Pinto

Read thread in its entirety: https://mbworld.org/forums/e-class-w...-latching.html

Attached Files

install tank recess.pdf (551.5 KB, 245 views)

Last edited by konigstiger; Mar 14, 2023 at 03:00 PM.

Mar 14, 2023 | 04:55 PM

gunbunny

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2012 E350

Quote:

Originally Posted by konigstiger

Read thread in its entirety: https://mbworld.org/forums/e-class-w...-latching.html

Read the thread and checked that. The gas cap cord was snipped off by the previous owner, so rotating the little stubby bit that's left doesn't do anything.

The problem isn't that it won't close. The problem is it won't stay closed.

Normal operation is this: The plunger switch at the 7 o'clock position is supposed to trigger the gas cap lock solenoid. The solenoid causes the latching rod to go in and out; when extended it goes through a flange on the filler door with a hole in it, thus locking it shut. Depressing the plunger switch with the filler door shut is supposed to cause the solenoid to retract the latching rod and the door opens.

My problem is that the plunger doesn't do anything. Locking or unlocking the doors activates the solenoid, but the plunger switch does nothing. (So when I lock the doors, the solenoid fires and the latching rod extends. Unlocking the doors, the solenoid retracts the latching rod.)

EDIT: I'm a dolt. I looked at it again. Apparently while there is only a little nubbin on the gas cap, there remained about 2" of tether on the filler door. And that 2" wound up on the gas cap rest on the filler door, thus popping it open. Apparently the plunger isn't a switch after all. I stand corrected and eat my slice of humble pie.

Last edited by gunbunny; Mar 14, 2023 at 06:00 PM. Reason: I'm a dolt

Mar 14, 2023 | 06:12 PM

pierrejoliat

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From: Pepper Pike Ohio

24 GLS580 '23 E450 4matic 12 E350 4Matic

Happens to all of us, welcome to the forum.

Mar 14, 2023 | 06:51 PM

CaliBenzDriver

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From: Silicon Valley

W212 MY'14 M276-3.5NA @75kMi

Cap... recap

For other future readers, the fuel door can fail to close for 3 distinct reasons -

In order of likeliness for ya :

cap cord gets in the way
ejector does not stay down
motorized latch is jammed in/out

Repair cost range from free to around $500. Warranty may sometimes be applied or not.
🤞

Content research courtesy of @konigstiger - Follow thread link for complete parts view in particular the $10 spring actuated ejector pin.

Last edited by CaliBenzDriver; Mar 14, 2023 at 08:32 PM.

Mar 14, 2023 | 10:57 PM

Quint22

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Joined: Jun 2022

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From: WA State, USA

2014 Cummins, 2014 E250 Bluetec

Quote:

Originally Posted by CaliBenzDriver

For other future readers, the fuel door can fail to close for 3 distinct reasons -

In order of likeliness for ya :

cap cord gets in the way
ejector does not stay down
motorized latch is jammed in/out

Or number 4, ya have auto lock enabled and it locks while filling up the vehicle so ya cant get the door shut/latched until ya unlock the vehicle. My car got me once lol.