Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help

Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

LinkBack Thread Tools Display Modes
Old 05-08-2004, 09:15 PM
fj bertrand's Avatar
Registered User
Join Date: Oct 2002
Location: North Central PA
Posts: 441
reserve light, fuel gage connected??

Is the reserve light on the fuel level system in the 240d, 300d etc
independant of the gage level pointer?

When my fuel gage is at or below the last hatch mark, the reserve light doesn't come on. When I fill up I can only fill up to about 2 gals of listed capacity. So, what I am thinking is that the gage and the reserve are not connected. what says the learned members of the group??

71 220D 169K wrecked
83 240D 118K sweet 4 speed
91 350SDL (one of the 60% good engines) 156K
84 300d (loaner to my sister) 189K
79 300SD (partswagen)
86 420SEL partswagen
70 220d (partswagen)
68 280s GASSER!!! under construction now
85 300sd 310K miles winter beater car retired
93 300d 2.5 turbo 168K wife's car
83 280SL euro 5 speed 155K
69 250S newest project 54K
Reply With Quote
Old 05-08-2004, 09:50 PM
sixto's Avatar
smoke gets in your eyes
Join Date: Jun 2000
Location: Eastern TN
Posts: 20,833
There are separate sensors as I understand it, but in the same assembly. The warning triangle should come on when you turn the key to glow.

95 S420
87 300SDL
Reply With Quote
Old 05-09-2004, 01:21 AM
Registered User
Join Date: Mar 2003
Location: Chimacum, WA
Posts: 80
Perils of an empty tank.

The gauge and the warning light senders are part of the same assembly and share a common ground connection. If you've never seen the warning light, it's possible that some part of its circuit is faulty.

You might consider refueling a little earlier, unless you enjoy hiking to the diesel pump and the subsequent bleeding procedure.


'84 Euro 300D, new (used) sender assembly
'85 300D
Reply With Quote
Old 05-09-2004, 02:03 AM
Registered User
Join Date: Apr 2004
Posts: 27
I just repaired the sending unit in my 74 240D. There was a copper ground wire inside of the sending unit that was part of the fuel warning light circuit. This wire was broken and prevented my reserve indicator from ever working. Additionally, there was a short circuit under an insulating fibre washer.

Reply With Quote
Old 05-09-2004, 04:42 AM
wolf_walker's Avatar
Zen And The Art Of Diesel
Join Date: Dec 2003
Location: Oklahoma City
Posts: 2,050
I pulled mine and cleaned it awhile back. The reserve light circuit is tied to the float. When the float reaches the bottem of it's travel, the light circuit is completed and it comes on. I checked the OHM reading on all the lines and they were in spec, gauge still off a little. I just adjusted the needle to point to exactly empty when the flat was at the bottem of it's travel. Works reasonably well, old car's fuel gauges are seldom precisly accurate. Light comes on every 450 miles or so, I put in 16 gallons, and repeat.
One more Radar Lover gone...
1982 VW Caddy diesel 406K 1.9L AAZ
1994 E320 195K
Reply With Quote
Old 01-27-2011, 06:25 PM
Join Date: Jul 2009
Location: Buffalo, New York
Posts: 142
Wow, 450 miles on 16 gallons!
Reply With Quote
Old 01-27-2011, 06:31 PM
Join Date: Jan 2011
Location: Colorado
Posts: 474
800 miles is possible if you maintain only 45mph on the highway.
Attached Thumbnails
reserve light, fuel gage connected??-picture-2.jpg  
Reply With Quote
Old 01-27-2011, 08:55 PM
Biodiesel300TD's Avatar
Join Date: Dec 2004
Location: Albany, OR
Posts: 4,845
The light comes on when the float inside the fuel level sender hits the bottom. It's possible that there is gunk built up on the bottom of your level sender keeping it from grounding and turning the light on.
'04 Jetta TDI Wagon
'82 300TD ~ Winnie ~ Sold
'77 300D ~ Sold
Reply With Quote
Old 01-28-2011, 10:02 AM
Oldwolf's Avatar
Join Date: Apr 2009
Location: Raleigh, NC
Posts: 1,017
Testing Reserve Warning Contact

The FSM details the procedure needed to test the warning light.

Test Warning Light

1993 W124 300D 2.5L Turbo, OM602.962
2000 Chevrolet Cavalier, 2.4L DOHC
2002 Ford Explorer, 4.0L SOHC
2005 Toyota Prius, 1.5L
Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 09:50 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page