ECU Loom Install Guide
Most
1.6 16v, 1.8T & 2.0 Petrol engines requires the additional ECU loom which
we can supply
The
ECU-Bulkhead loom wiring is as follows:
Fitting
the additional wires into the bulkhead connector plug
Once unplugged
from the captive female socket in the bulkhead connection box, the black plug
will look like this, with perhaps only 2 wires already installed:
Using a thumb or a
screwdriver, push firmly on the end of the purple locking clip to slide it
across into the released position, as shown below.
Take the 4
terminated wires of the supplementary wiring loom and insert into the following
sockets as shown, ensuring that the receptacles are correctly oriented as per
the pre-existing connections. Each terminal should 'click' home when fully
inserted.
Once assembled,
push back the locking clip to secure the terminals.
The connections
are shown below for reference, and the wires that may already exist are listed
for reference :
1 - Blue (OE colour Blue&Grey)
2 - Red (OE colour Red&Yellow)
3 - Black (OE colour Black&White)
4 - Red &
Black
5 - White &
Yellow
6 - (none)
7 - (none)
8 - (none)
9 - White
10 - (none)
Feed the
supplementary loom out from the bulkhead connection box and alongside the main
vehicle wiring up to the ECU. On my vehicle, the bulkhead connection box
offered a spare outlet with a blank rubber grommet through which I fed the new
loom.
On newer models
there may not be this option as the bulkhead connection box uses a bolted down
black plastic cover in place of the hinged lid. If this is the case on your
vehicle, then drill an additional 10.0 mm diameter hole through the
plastic cover next to the main loom exit grommet and make use of the sleeved
grommet supplied with the new loom.
Fitting the additional wires into the ECU plug
The un-terminated
ends of each of these 4 wires go to the larger of the two ECU connectors. The
ECU is mounted under the middle of the windscreen, and is accessed via the
engine bay once the scuttle panel is removed. Note that the vehicle battery
must be disconnected before commencing this stage of the installation
To release the ECU
plug from the ECU, reach behind the incoming loom to the plug and slide across
the black 'T' shaped locking clip away from the connector towards the offside
of the car. Once this has been released the plug can be pulled away from the
ECU.
To remove the
wires from the ECU connector, snip the cable tie and unclip the cover. Pull out
the long pink retaining clip from the side of the connector, and pull upwards
on the triangular separating piece that is between the two banks of
connections.
It should now be
possible to pull the two connector blocks, black and white, out of the housing.
Each wire goes into the connector through the red rubber seal, then is crimped into barbed sections of the connector
pin.
Before fitting
the new loom to the ECU plug, trim the length of the free wire ends so that the
sleeving of the loom will cover the cables up to the
ECU plug cover and leaves no coloured wires visible.
Note at this point
that the ECU pin connection numbers for the CC loom are different between the
different models. For 1.8T engines, the
connections to be made are as follows
ECU Connections
|
LOOM COLOUR |
OEM COLOUR |
1.8T |
|
BLACK |
BLACK/WHITE |
T121/38 |
|
RED |
RED/YELLOW |
T121/57 |
|
BLUE |
BLUE/GREY |
T121/75 |
|
WHITE |
WHITE |
T121/76 |
To insert the new
connections, push the wire through the rubber seal and place it alongside the
relevant pin. Next, use a medium sized flat screwdriver blade to push the new
wire into the barbs of the connector pin.
Once the wire is
pushed down, bend around the two retaining tabs at the top of the pin to hold
the wire in place using a small flat bladed screwdriver.
Re assemble the
connector and fit a new cable tie to hold the cover to the looms. Use
additional cable ties to secure the CC loom to the existing wiring loom where
necessary.
TIP - Now is a
good time to recondition your wiper motor linkage before you refit the motor
assembly to the car - the spindles that locate each wiper arm often seize up on
Golf based models.
Refit the cover to
the bulkhead connection box, refit the wiper motor and don’t forget to
reconnect the wiring plug to the motor if you removed the motor completely.
Refit the scuttle panel cover (easier if the pollen filter cover is fitted
separately), and then the windscreen wiper arms.
Before
reconnecting the battery, turn the ignition switch to the on position to avoid
any voltage spikes upsetting the airbag system. With the battery connected and
ignition switched on, slide the cruise control switch to on and you should see
the cruise control light illuminate on the instrument panel. Test drive and
enjoy!
