Author Topic: Fuel Pump HIDDEN FUSE discovered from wiring diagram 73 280se D-Jet  (Read 88 times)

beytan

  • Newbie
  • Posts: 1
  • 280se W116 D-Jet owner
  • Location: Hampshire UK
Hi All, This is my first post so I hope it is useful.

I recently had an issue with my fuel pump not priming after pulling out my instrument cluster and having a stray brown lead (earth?) touch the keys whilst ignition on. It sparked and blew instrument panel fuse which is an 8amp. I only had 16 and 25 amp fuses so decided to remove the cigar lighter fuse (which was oddly 8amp yet showed 25amp on the fuse sheet) so my instrument panel came back to life as I have been trying to fix a unresponsive temp gauge.

Anyway... The fuel pump wouldn't prime so I changed all the relays as this had not been dome since i bought the car but still no fuel pump?

I luckily had the engineers manual set for the 114/116/107 and looked at the wiring diagram only to find that the fuel pump is fused by the same cigar lighter fuse!

Here is the interesting part. The fuse panel card asks for a 25amp fuse for the cigar lighter but does not list the fuel pump anywhere.

The wiring diagram shows an 8amp fuse for the fuel pump using the same cigar lighter fuse (no. 6 )

Mercedes have actually made an error by doing this as we all know that problems with incorrect fuse amperage's can cause all sorts of issues.

So.. I now have 8amp where the fusebox card tells me there should be a 25amp and won't be smoking any cigars soon. all is good with the car and I will continue to post when I fins anomalies like this.

Hope this is useful. :)
Beytan