"RED" Reserve Warning Light

[Walt Marsh]

I am restoring a late U.S. Model 1971 280SL to factory specs.
Vehicle equipped with AC, Automatic Transmission, Power Steering, etc.

Already connected wiring harness to main fuse panel with assistance form the U.S. 280SL Color Wiring Diagram, Headlight Switch Diagrams, etc.  located on this site.
Wired instruments, and they're ostensibily operating with proper power and dimmer control through Reostat.
Checked functionality and noticed the "red" reserve warning light in center Instrument cluster not operating properly.
Gas tank empty (i.e. Bone Dry) - removed and inspected sending unit/float mechanism in tank; it works fine.
However, still no red "Reserve" warning light on instrument cluster.
All other lights on cluster operational.

In full disclosure, Palo Alto Speed-O-Meter recently restored all my instruments to show quality specifications.
Initially I thought perhaps a bulb burned out.
So I removed center instrument cluster and checked bulbs with bypass tester - all bulbs work fine.

Anyone got any experience with this particular problem???


Walter

[Walt Marsh]

Hello Pagoda Group Members,

I have resolved the issue with my Reserve Warning light.
After pulling out the Sending unit and taking it apart I noticed the ground wire which makes contact with the two points at bottom was shorted out.
Fixed it by soldering similar gauge copper wire in its place and verified proper operation by turning sending unit upside down and right side up simulating full and empty tank scenarios.

Walter

[Shvegel]

Nice job!  Saved yourself $300 to boot.

[jeblack123]

I have the opposite problem in that may reserve fuel light remains on constantly. An thoughts.

James

[Walt Marsh]

Hello Jeblack123,

Clearly, something interfering with your sending unit float or contacts.
When I took mine apart I noticed it had a small amount of dirt deposits inside the float tube in addition to the ground wire was shorted out.
Depending on your vehicles condition you may have bunch of dirt/corrosion build-up from your gas tank.
I suggest removing, inspecting, and cleaning if necessary.
It can be simply done by removing it from your gas tank through your trunk.

Walter