I have read that the lower harness is not necessary to replace because it does not get as hot as the upper harness. Heat and humidity are what causes the bio-material made wire insulation to excelerate decomposition.

The top of the engine and near the MAF get hot as does the inside of the throttle actuator case. Humidity can include external and condensate.

I have read about the interior harness, but also not typical to replace.

I have read about the battery cable/harness being replaced, but I am not sure what that means.

I won't ever believe someone telling me not to worry about the lower engine harness. My upper was shedding plastic like raindrops. Connectors became "dust" when I pulled on them. The dealer said same thing, usually the upper harness. The best way is to go underneath and check the feed at the alternator and the oil sender, easy to inspect. Mine were brittle and had exposed wiring. The plastic wiring cover is crap but not overly expensive to replace and its not hard to change. Just takes your time and good lift equipment to get underneath. Steve

Most likely the battery cable is ok. It's the smaller wires that have bad insulation. A few dollars for wire and a little soldering and you can DIY as I did. But you have to do some connections from under car. You don't need a lift, just a couple of jack stands under the front. Connector [photo 3] uses pin connections to wire. De-solder and reuse them.

Photos 2 & 3 at end of thread are of cable through grommet at oil filter and connector [to its right when facing engine].

Oil level = Brown/Black [left side, front, bottom of block]
Oil Pressure = Brown/Green [left side, below oil filter]
Solenoid = Purple/White [on starter]

PS Good to disconnect battery when messing with B Harness.

PPS Replacing the positive battery cable is a PIA because it runs from driver side to passenger side and is covered by all the plastic mouldings. But if you're going to do this cable you might as well R&R the windshield wiper assembly to clean & lube and do same to climate control fan motor. And replacing the thin plastic vac tubing is also a good idea. Been there, done that.

Bob,

The link did not work for me. I get a message "We're sorry The file you were looking for was not found on our server Please try using our search engine above" from the peachparts website.


Thanks,
Jim

I just went into limp mode recently due to my ETA. The wires are show, so I send it off to BBA for rewiring. I took a picture of the wires, you can see how bad it is.

__________________
93 Toyota Corolla 177K
95 S 500 coupe 82K
92 400E 180K (SOLD)
94 E 420 150, blown gaskets (SOLD)
http://www.kanio.net/mercedes_signature.jpg

Photo of Connector [re-solder pins to wires] for Oil sensor & Solenoid] the lid is open in the pik to see connections.

try here

http://www.peachparts.com/shopforum/attachment.php?attachmentid=32684&d=1144886223

System won't allow me to reload a photo of harness behind oil filter, but it really isn't hard to find.