Door modules - Just-Auto.com

Chapter 1 Introduction Page 1
Chapter 1 Introduction
What is a door module?
A door module typically consists of a rubber-sealed carrier made from plastic
or metal. Aluminium and magnesium are also being considered by
manufacturers to reduce the weight of the carrier still further. A variety of door
components are then fitted onto the carrier, forming a ‘cassette’, such as the
window lift mechanism, locks, electric motor to operate the wing mirror, wiring
harness, various switches, loud speaker and a cable that connects the latch to
the inner release handle. The carrier plate is then tested and sealed to the
outer door.
The level of componentry however, can vary immensely from one trim level to
the next. Manufacturers typically carry 90 different part numbers for each of
the four doors. Whereas one model may offer a manual latch with central
locking, another may include an electric latch with super-locking. There are five
different types of latch offered for the Golf, for example. There are more than
200 front door module combinations alone, ranging from all-manual to allelectronic.
While the majority of door modules use a steel carrier, plastic solutions are
becoming increasingly popular. Over the past few years, there have been a
number of arguments ‘for’ and ‘against’ the use of plastic over steel carriers.
Delphi’s Superplug, for example, was a well-publicised effort to use a plastic
carrier. Klaus Caspers, programme manager for Delphi’s door modules, said:
“The technological advancement in new resins and manufacturing processes
for plastic carriers has evolved to the point where plastic is being more
favourably received as an alternative to steel. With the volatility of steel prices
in the market, OEMs are searching for alternative materials, and plastics is one
material that is being considered more favourably. More OEMs are considering
plastics and are not as quick to dismiss it as an alternative material to steel.”
The trend in both Europe and the US is toward increasing complexity of the
door componentry, adding more electronic functions and, in some cases, the
glass itself. VW and Porsche are arguably furthest down that route. Developed
by Brose, the door modules for the VW Touareg and Porsche Cayenne show
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