I am working on a 1992 400sel, the battery light is on while running, I have checked for charging at the battery and the alternator, both only show battery voltage. I have battery voltage on the main wire on the alternator, but nothing on the smaller wire that comes from the ignition switch with KOEO. I have had the alternator tested and it tests good, the battery also tests good. I have one fuse that is bad but it is for the seats, it is another problem for another day. I am trying to trace the problem down on the smaller wire to see if it is a bad ignition switch or possibly a broken wire or a bad connection somewhere. Can somebody pass on some information to help me trace it down or at least point me in the direction I need to be looking.
Not Charging, Good Battery and Alternator
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1972 220 D, 1974 450SL, 1995 E300D 2002 S430, 1976 300D, 1986 SDL, 1982 SD
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Change the relevant fuse anyway. Not the seat fuse, but the one that would be involved in charging circuit. Not sure how to track it back to a short. But the fuse trick works for me
I have been doing some more checking on this car, the schematic is helping by the way, thank you, I have found several wires where the insulation on the has become brittle and has cracked and fallen away, one of these is to the alternator, several go to the starter so I am thinking that is where my problem is. Is this a problem with the harness on these cars that is causing them to do this or could it be due to the fact that the car has sat for awhile before it came to me to be worked on? Also if it is a problem with the harness on these cars is it better to replace the entire harness in the engine bay or just splice in what needs replaced? the wires do not appear to have gotten hot, there is no melting anywhere and no discoloration of the wire itself. I have found pieces of the insulation where it has just cracked and fallen off.
1972 220 D, 1974 450SL, 1995 E300D 2002 S430, 1976 300D, 1986 SDL, 1982 SD
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2,728 Posts
YOu have encountered the self destructing wiring harness. It was mandated by some eco idiots in the 90's. Best solution is to find a local fellow to weave you a loom. Failing that, you can order a new one. Mid 90's, Mercedes figured out that the wires were a bad idea and made a better set of wires.
1992 600 SEL x 3, 1998 E430, 2002 E320T 4matic, 1971 300SEL 3.5 project plus 4 more W108, etc
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765 Posts
Yes, it certainly sounds like the lower engine harness. It is the easiest one to rebuild and you should be able to do it yourself as I did my 600 harness with no real access issues and being you have a lil bit more room with a V8.
Probably looks like the image below under the sheath. I do recomend carefully measuring the entire harness before dismantleing it. Second image is the scetch under the rebuilt harness for inspiration. Third image illustrates where it fastens to the firewall an the passenger side. You will have to unfasten a heat shield to see it.
Probably looks like the image below under the sheath. I do recomend carefully measuring the entire harness before dismantleing it. Second image is the scetch under the rebuilt harness for inspiration. Third image illustrates where it fastens to the firewall an the passenger side. You will have to unfasten a heat shield to see it.
Attachments
Can anybody give me the part numbers for the upper and lower engine harness, I found a number for an upper harness (A1405409505) elsewhere in this forum but want to make sure it is the correct one. I am finding that the 400 did not come with a 5.0 standard engine, yet the tag under the hood shows this as being a 5.0, can anybody tell me the reasoning as to why this car has a 5.0 instead of the 4.2? Is it due to the fact that it is an SEL model and not just an SE?
Paul, sign up at http://epc.startekinfo.com/epc/login.jsp
It's free in the US if you enter a credit card number to verify yourself. Once you have an account you can enter your VIN and be sure to get the correct part number for your car.
It's free in the US if you enter a credit card number to verify yourself. Once you have an account you can enter your VIN and be sure to get the correct part number for your car.
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