Mercedes-Benz ML320. Manual — part 509

Overview of authorized reworking on wiring harnesses

into the body



Lines get pinched in clamps
or trim parts

Fatigue



Lines routed or secured
incorrectly



Excessive stress



Open circuit in wiring

Corrosion



Due to contact with acids or
aggressive fluids (e.g. brake
fluid, antiseize, coolant
additives, fuels, lubricants),
water penetration due to
defective seals, use of high
pressure cleaner



Wiring harness covered in
paint after paint repair



Hardening of insulation due
to contact with an
incompatible agent (e.g.
solvent)



Line open circuit, contact
pairing not longer conductive
(transition resistances)



Insulation and wires
damaged



Lines or connections to
contacts



High line resistance



Components with sharp
edges



Corrosion

Assembly fault



Use of incorrect tools, e.g.
wrong crimper or wrong
release tool



Damaged contacts or lines
through use of unsuitable test
tools (e.g. probes)



Lines pinched or screwed in



Loose contacts in plug
connections



Wrong contacts crimped



Undesirable transition
resistances



Open circuit in wiring, short-
circuit



Insulation damaged

Type of fault

Remedial action

Faulty contact part

Contact part



missing



wrong part



deformed



Install new contact part

Contact part not engaged properly



Latch contact part, then check, and replace if
necessary

Not all individual wires are crimped



Cut off contact part and install new part

Insulation also crimped



Cut off contact part and install new part

Conductor not far enough in contact part



Cut off contact part and install new part

2004 Mercedes-Benz ML350

1998-2005 GENINFO Overall vehicle - 163 Chassis

me

NOTES REGARDING PLUG CONNECTIONS - AH00.19-P-1000-06A

Contact part not tin-plated



Cut off contact part and install new part

Sleeve



oxidized



wrong part



Cut off contact part and install new part

Not soldered properly/dry solder joint



Resolder contact part and replace if necessary

Plug-in area full of solder



Cut off contact part and install new part

Fault with housing

Screw connections loose



Tighten screw connections using an adjusted
torque wrench, replace if necessary

Screw connections



wrong part



damaged



Install new screw connections (cable
connectors)

Coupling housing or plug housing damaged



Install new coupling or housing



Check contact and replace if necessary

Coupling housing or connector housing not closed
properly



Close coupling or housing properly

Cap screw in handle recess



missing



loose



Tighten cap screw, replace if necessary

Cable fault

Insulating tubing damaged



Rewrap with PVC tape

Insulation damaged



Cut through affected line at damaged area and
repair using Raychem repair method

Insulation pulled up



Cut through affected line at damaged area and
repair using Raychem repair method

Wrapping defective



Rewrap

Splashes of solder on cable



Carefully remove splashes of solder using a
suitable tool without sharp edges.

Grommet



missing



wrong part



installed incorrectly



damaged



Pull on new grommet, or install correctly

2004 Mercedes-Benz ML350

1998-2005 GENINFO Overall vehicle - 163 Chassis

me

Model 124, 126, 129, 140, 163, 164, 168, 169, 170, 171, 199, 202, 203, 208, 209, 210, 211, 215, 216, 219, 220,
221, 230, 240, 245, 251, 414, 461, 463

Terminology of plug connections:

The coupling and the plug form a plug connection. The female contact and the contact pin form the contact pair.

Illustrated: SLK family, coding A (with circular conductor)

Fig. 11: Identifying Plug Connections - SLK Family, Coding A (With Circular Conductor)

Plugs and couplings

The plugs and couplings are grouped into families in the same way as the contact groups (e.g. SLK, JPT). The
type and shape of the receptacle chambers in the housing is the major differentiating characteristic. Different
contact families may be installed in the same housing. In addition, different codings (e.g. A, B, C) may exist
within the same plug/coupling family.

Codings are special profiles or teeth on the housings of the coupling and the plug, which may be marked in
different colors (e.g. black, white, violet).

These ensure that connector pairings can only be made with the same codings.



Safety and restraint systems (airbag, emergency tensioning retractor, roll bar) have yellow, orange, or red
plug connections for easy identification.

Part number assignments

The housings are assigned according to the part numbers on the housings. On housings made up of several
components, the number on the external housing is critical. (When ordering, all the individual part numbers
must be ascertained.)

This method of identification by means of part numbers can be used when referring to the literature.

Contacts

2004 Mercedes-Benz ML350

1998-2005 GENINFO Overall vehicle - 163 Chassis

me

A distinction is made between the contact pin and the female contact. Each contact pin and each female contact
can be clearly assigned to one group or "family" (e.g. SLK, JPT). Within these families distinctions are made
according to the cable cross section and whether there is single-strand insulation for watertight connections. The
contacts are also distinguished by their coating (tin, gold or silver).

The contacts are fastened to the cables by means of crimping. ?

Crimp connections

These are used to attach the female contacts or contact pins to the cable. Each contact type must be crimped
with the aid of specifically assigned die sets using a pair of pliers. Determining factors: contact family, size of
cable cross section, with or without single-strand insulation.

Only lines up to 4 mm shall be crimped.

Unpinning

This requires a release tool appropriate to the contact family in order to remove female contacts and contact pins
from plugs and couplings.

On some plugs and couplings the housings must first be disassembled and unlocked (secondary release)
according to the instructions before the actual unpinning.

Contact materials

The contacts used in the interior of the vehicle are primarily tin/tin combinations. Those used on the exterior
and in the splash zone are generally silver/silver. Safety systems (particularly the airbag) are equipped with
gold/gold contacts.

Only "identical" contact pairings are permitted for repair work.

NOTES ON SOFT SOLDERING - AH00.19-P-1000-07A

Model 124, 126, 129, 140, 163, 164, 168, 169, 170, 171, 199, 202, 203, 208, 209, 210, 211, 215, 216, 219, 220,
221, 230, 240, 245, 251, 414, 461, 463

General information

Soft-soldering is a process for creating an inseparable join between two or more metal parts using additional
metals (e.g. soldering tin). The solder melting temperature lies below the melting temperature of the metals to
be joined and is lower than 450°C.

The connection is created by wetting the joint locations with hot liquid solder, without melting the parts to be
joined.

The joining procedure is assisted by using a flux, which releases surface oxides on the parts to be joined,
eliminating and preventing surface films (e.g. greases).

2004 Mercedes-Benz ML350

1998-2005 GENINFO Overall vehicle - 163 Chassis

me