Glow plug relay (part 2)

Thanks for all the help and advice on the glow plug relay post. I managed to source a replacement from Mercedes, not cheap but hopefully do the trick.

Question is - before I put it in, is there other things I should look out for which might cause the relay fuse to blow again? Wiring, earthing etc? I have new battery and glow plugs....

Problem before was that the relay was staying live and draining the battery, had some great advice re: fixing with soldering but wasn't super confident in doing so. Any diagrams or photos of wiring locations would be great!

Thanks again

1998 2.3 208D

There is a scanned copy of a Peter Russek manual saved on the DIY Sprinter website... http://www.diysprinter.co.uk/refere...10_307_308_310_408_410D_service_manual_EN.pdf

Try looking at the wiring diagrams but they may be too generic to help.

Keith.

Bobbycrabb said:

...

Problem before was that the relay was staying live and draining the battery, had some great advice re: fixing with soldering but wasn't super confident in doing so. Any diagrams or photos of wiring locations would be great!

Thanks again

1998 2.3 208D

Click to expand...

The relay may not have been "staying alive" as in the coil being powered. There is some history of the GP relay contacts sticking together which keeps the GP's energized. The GP's use quite a bit of power. Did the battery drain fairly quickly?

You own a T1N. Your questions for your model should be posted in the T1N section. It may help others in the future if you provide the MB GP module part number that they supplied you.

vic

Bobbycrabb said:

Thanks for all the help and advice on the glow plug relay post. I managed to source a replacement from Mercedes, not cheap but hopefully do the trick.

Question is - before I put it in, is there other things I should look out for which might cause the relay fuse to blow again? Wiring, earthing etc? I have new battery and glow plugs....

Problem before was that the relay was staying live and draining the battery, had some great advice re: fixing with soldering but wasn't super confident in doing so. Any diagrams or photos of wiring locations would be great!

Thanks again

1998 2.3 208D

Click to expand...

I would not recommend replacing expensive components unless and until proper diagnosis has determined that the glow plug relay is the Cause of your Complaint. If there is an electrical problem elsewhere that is causing the glow plug relay to remain energized, then replacing the glow plug relay would be the last thing you'd want to do.

Before installing the new module test all your glow plugs for a short circuit to ground. The new module should hopefully have self-resetting solid state relay design, but best to avoid any chances.

Midwestdrifter said:

Before installing the new module test all your glow plugs for a short circuit to ground. The new module should hopefully have self-resetting solid state relay design, but best to avoid any chances.

Click to expand...

And that's just one part of the circuits that are involved.

The glow plug module is wired straight back to the ECM via the small two-pin plug, and gets its commands over the black/red Glow Plug Control wire. It is not a simple on/off interface, it is a communication link, so needs a good connection - what doesn’t?
Chances are this link is fine, and your old module relay had welded closed as described above, but it’s more thorough to check the control wire for a ground fault (though this should throw an ECM code) with the ECM harness unplugged.

You stated you’ve got new glow plugs, but harness damage is possible so testing the six pin plug for shorts between pins is also a good idea. Either disconnect the wires at the plug ends, or measure resistance pin to pin and look for a low outlier.

-dave