Time to call in the experts - Page 2 - PeachParts Mercedes-Benz Forum

mtbguy · #16 09-20-2009, 09:31 PM

AHA- I didnt know that- it is indeed a late year model one made in November.
Is the engine harness the main problem or are all the other wires suspect also?

When I removed the harness the number five wire had a short depending on how you bent the wire, and there was a "hard spot" in all of the wires where they were brittle around the number three cylinder part of harness- it seemed to be old age/heat related. The number 1-4 cylinder wires were Ohming out around .3-.5 Ohms.

It took me about two hours today, but I purchased heavy duty copper strand wire that was ten gauge and made a new wire harness crimped and soldered onto the old end fittings. I ohm checked it and the new harness is Ohming out lower at around .1 Ohms and the wires are 10 gauge instead of factory which I think was 14 gauge (or possibly 12).

I also learned something today when at the auto parts stores in the area. It is almost impossible to find the 80 amp strip fuse for the glow plug relay, but I found a 80 amp fusible link for $2 at autozone that almost matched up with the holes. I bent it in about 1/4 inch with vice grips and it fits on the relay terminals fine. I plan on getting the real strip fuses from Buy MB parts this week, but this will work in a pinch if you just need to get the relay working again to get home and are stranded. It sticks up a bit so the snap on cover wont fit, but this is just to get me around for a day or two.

Now its time to reinstall the glow plug and put in my new custom harness. Wish me luck... Thanks everyone for your help so far!!!!!!!

Bio300TDTdriver · #17 09-20-2009, 09:42 PM

Quote:

Originally Posted by mtbguy

AHA- I didnt know that- it is indeed a late year model one made in November.
Is the engine harness the main problem or are all the other wires suspect also?

When I removed the harness the number five wire had a short depending on how you bent the wire, and there was a "hard spot" in all of the wires where they were brittle around the number three cylinder part of harness- it seemed to be old age/heat related. The number 1-4 cylinder wires were Ohming out around .3-.5 Ohms.

It took me about two hours today, but I purchased heavy duty copper strand wire that was ten gauge and made a new wire harness crimped and soldered onto the old end fittings. I ohm checked it and the new harness is Ohming out lower at around .1 Ohms and the wires are 10 gauge instead of factory which I think was 14 gauge (or possibly 12).

I also learned something today when at the auto parts stores in the area. It is almost impossible to find the 80 amp strip fuse for the glow plug relay, but I found a 80 amp fusible link for $2 at autozone that almost matched up with the holes. I bent it in about 1/4 inch with vice grips and it fits on the relay terminals fine. I plan on getting the real strip fuses from Buy MB parts this week, but this will work in a pinch if you just need to get the relay working again to get home and are stranded. It sticks up a bit so the snap on cover wont fit, but this is just to get me around for a day or two.

Now its time to reinstall the glow plug and put in my new custom harness. Wish me luck... Thanks everyone for your help so far!!!!!!!

After it works with the new wires, try it with the old relay. You won't need a fuse if the old relay is still OK.

mtbguy · #18 09-21-2009, 12:10 PM

Whew! I installed the new harness (without removing intake) man that was a houdini act needing three arms pain in the rump. Lots of needle nose pliers, magnets, screwdrivers and such to guide wires into place. It felt like I was doing surgery on someone via remote control. I think I should have just removed intake again- it would have taken less time. New harness is in and working- the glow plug system and light works like its supposed to again and the glow plug cycle seems faster- I think the new large diameter wires are helping it heat up quickly.

I now have a brand new relay and the old one(which still works fine). I think i will keep the old one (circuit breaker type) in until it dies someday and have the fused one as a spare.

Thanks to everyone for your help with this- especially Kingdoc, Diesel 911,Bio300 for the diagnostic wire tool I made that finally cracked the code!

I the new harness lives as long as the original did I will be happy. I should be ready for cold starts this winter now with a fresh harness and five new glow plugs.

compress ignite · #19 09-21-2009, 07:28 PM

I "think" the wiring harness problem was limited to the engine harness.

Cr from Texas · #20 09-21-2009, 07:32 PM

Quote:

Originally Posted by mtbguy

Whew! I installed the new harness (without removing intake) man that was a houdini act needing three arms pain in the rump. Lots of needle nose pliers, magnets, screwdrivers and such to guide wires into place. It felt like I was doing surgery on someone via remote control. I think I should have just removed intake again- it would have taken less time. New harness is in and working- the glow plug system and light works like its supposed to again and the glow plug cycle seems faster- I think the new large diameter wires are helping it heat up quickly.

I now have a brand new relay and the old one(which still works fine). I think i will keep the old one (circuit breaker type) in until it dies someday and have the fused one as a spare.

Thanks to everyone for your help with this- especially Kingdoc, Diesel 911,Bio300 for the diagnostic wire tool I made that finally cracked the code!

I the new harness lives as long as the original did I will be happy. I should be ready for cold starts this winter now with a fresh harness and five new glow plugs.

So, will you let the kids play in the car again?

I wonder what made if fail - did the kids also have the keys?