Glowplug relay wires are toast - PeachParts Mercedes-Benz Forum

freesoul · #1 01-03-2009, 10:46 PM

I was using the guide from Dieselgiant to troubleshoot my problem which was the glowplugs didnt come on right away, and they would also come on intermittently when the vehicle was running.

I needed to go no farther than visual inspection- see pics below. I did test the resistance and on all but one it was around 8-10. One of them didnt even measure a reading.

So- my question is how involved is this repair?

jbach36 · #2 01-03-2009, 11:01 PM

HA!

Brian Carlton and I were just talking about this very thing, because I just did my glow plugs. Rather than a bunch of posts along the way, going through blindly since nobody has done a step by step from front to back, I am a big proponent of DIY articles for such common repairs.

I have just finished a rough draft of my changing glow plug DIY. Do you want me to send you a copy? Email me directly, and I'll send it to you.

Mine is for a 1991 300d,

jeff

Bio300TDTdriver · #3 01-03-2009, 11:03 PM

I hate to be the bearer of bad news, but that is probably the tip of the iceberg. Do a search for wiring harness. In the 90s MB used a biodegradable material that worked a little too well. You should check some of your other wires.

Jeremy5848 · #4 01-03-2009, 11:28 PM

Great photos! Poster child, alas! My wife's '96 is similarly afflicted although we have not had a lot of problems . . . yet.

Jeremy

freesoul · #5 01-04-2009, 12:11 PM

Quote:

Originally Posted by Bio300TDTdriver

I hate to be the bearer of bad news, but that is probably the tip of the iceberg. Do a search for wiring harness. In the 90s MB used a biodegradable material that worked a little too well. You should check some of your other wires.

crap! Is it possible to just replace this part of wiring or is it tied in to the whole harness? What are other places I can easily examine wiring without removing covering?

C Sean Watts · #6 01-04-2009, 12:42 PM

Quote:

Originally Posted by freesoul

crap! Is it possible to just replace this part of wiring or is it tied in to the whole harness? What are other places I can easily examine wiring without removing covering?

It will come back and haunt you. My cousin has a '95 C class gasser and he had the whole thing done (with labor) for $1600. He also had some other stuff done at the time and IIRC it was over 10 hours.

I think the whole (everything under the hood with correct connectors) harness was about half that.

freesoul · #7 01-04-2009, 12:59 PM

Please tell me that a new harness is made from better material and will not need to be replaced in another 13 years....

unkl300d · #8 01-04-2009, 04:33 PM

I bought my harness replacement from Fastlane (Phil) and he said it was upgraded to normal wire sheathing, not the bio crap.
my application 1995 C280

mobetta · #9 01-04-2009, 09:46 PM

I did not know that mercedes used that biodegradable wiring crap, too-

sounds like the same issues volvo had in the 80's. I avoid 82-87 bricks for that reason.

what are the bad years for mercedes?

lakerat · #10 01-07-2009, 09:01 PM

After looking at some of my wires in the engine bay it will be a miracle if the airbags work when I need them.

Jeremy5848 · #11 01-07-2009, 09:48 PM

Quote:

Originally Posted by mobetta

. . . what are the bad years for mercedes?

Early '90s up through at least 1996, or so I have heard. My '96 E300D (early W210) definitely has the problem although not as bad as some folks have had with theirs. AFAIK, the only problem with the early W124 cars (for example 1987 300D Turbo) is the wiring to the rear windows – and that is a stranded wire gauge problem, not an insulation problem. Don't know about c-class or s-class cars of that era.

Jeremy

freesoul · #12 02-10-2009, 10:52 AM

OK so I called Phil who has it for $430, the dealer $444, and a local shop $400. I want to make sure I am getting the right harness, the dealer gave me a part # 1244404032 for a 95 E300d- he said it was a preglow/something harness and there may be a separate harness for alternator.

Am I ordering the right one?? Also I may try to do this with a friends help, if I was to take it to a shop does anyone have an estimate on how many hours this would take?

funola · #13 02-10-2009, 11:41 AM

Holy crap! Do these biodegradable harnesses all fail or only some? Anyway to treat it so they don't fail? Was there a recall on it?

Jeremy5848 · #14 02-10-2009, 12:48 PM

Mercedes never did a recall. Some cars seem to see this problem more than others but all are at risk. Short of rewiring, be gentle any time you work with or work around the wiring.

TMAllison · #15 02-10-2009, 01:19 PM

Supposedly the harness was upgraded sometime during the 96 model run.

Order your harness using your VIN so you get the right one.

Mine was done on the 99 because of a different problem; was approx $600 at the dealer IIRC. Your's is much simpler.