General information on towbar electrical socket of Fiat Punto

1-2 Although the following information depicts the installation and connection of a specific make of electrical socket, the procedures can be used as a general guide for all installations.
3 Prior to starting, read through the entire procedure to familiarise yourself with the work involved and ensure that all necessary tools and equipment are available.
4 Check that all rear lights are working correctly prior to installation, then ensure that all electrical circuits are switched off.

Materials

5 Unpack the installation kit and check that all the following parts are contained;
a) Pre-wired electrical socket.
b) Socket mounting plate.
c) Audible warning unit.
d) Cable snap connectors.

Socket installation on Fiat Punto

6 Remove the rear bumper.
7 If the towbar is not fitted with an electrical socket mounting plate, fit the plate supplied with the kit, using the existing towbar mounting bolts.
8 Where a mounting plate is incorporated in the towbar of Fiat Punto, locate the electrical socket on the mounting plate, insert the screws and secure with the retaining nuts (see illustrations).



Locate the electrical socket on the mounting plate and insert the retaining screws ...



... then secure the screws with the retaining nuts


9 From within the luggage compartment, extract the rubber grommet for the number plate wiring harness from the inner body panel.
10 Feed the Fiat Punto socket wiring loom up through the outer hole in the body rear panel, then through the inner hole and into the luggage compartment (see illustration overleaf)



Feed the socket wiring loom through the hole in the body rear panel into the luggage compartment


11 Suitably enlarge the hole in the rubber grommet using a sharp knife, or by careful use of a drill. Take care not to damage the number plate wiring harness insulation when enlarging the hole.
12 Feed the electrical socket wiring loom through the rubber grommet and into the left-hand side of the luggage compartment (see illustration). Refit the grommet to its location, then refit the rear bumper.

Wiring connections

Note: All Punto models have bulb failure monitoring. If a tow bar is wired without including a "smart" relay the failure warning light wilt be illuminated when the trailer is connected.



Insert the wiring loom through the rubber grommet


13 The electrical socket pin connections in Fiat Punto, wiring cable colours and vehicle connections are as follows:
Towbar electrical socket Cable colour Vehicle connection
Pin 1 Yellow Yellow of audible warning unit.
Pin 2 Blue Pear foglight wiring in vehicle harness.
Pin 3 White Earth connection.
Pin 4 Green Green of audible warning unit.
Pin 5 Brown Right-hand tail lights in vehicle wiring harness.
Pin 6 Red Stop-lights in vehicle wiring harness.
Pin 7 Black Left-hand tail lights in vehicle wiring harness.
14 The audible warning unit wiring cable colours and vehicle connections are as follows:
Wire Vehicle
colour connection
Orange Left-hand direction indicator in vehicle wiring harness.
Slate Right-hand direction indicator in vehicle wiring harness.
Black Earth connection.
Green To pin 4 of towbar electrical socket.
Yellow To pin 1 of towbar electrical socket.
15 Using a sharp knife, carefully cut off approximately 150 mm of the black cable sheath from the end of the electrical socket wiring loom of Fiat Punto (see illustrations). Take great care not to cut through the insulation of the wires inside.



Cut the socket wiring cable sheath approximately 150 mm from the end...



... then remove the cut portion from the loom


16 Strip off approximately 10 mm of insulation from the end of the audible warning unit and towbar socket yellow wires.
17 Connect the two yellow wires together using an in-line connector and crimp the connector securely using a crimping tool (see illustrations).



Connect the two yellow wires together using an in-line connector...



... and crimp the connector securely using a crimping tool


18 Repeat paragraphs 16 and 17 to conned the two green wires together.
19 Strip off the insulation from the end of the Fiat Punto towbar socket white (earth) wire, and the audible warning unit black (earth) wire. Join the two wires together using a tag connector and securely crimp the connector (see illustration).



Join the two earth wires together using a tag connector


20 Undo the nut securing the vehicle wiring junction box to the rear body panel on the left-hand side. Slide the tag connector with the two earth wires over the stud and secure with the retaining nut (see illustrations).



Slide the earth wire tag connector over the junction box mounting stud...



…and secure with the retaining nut


21 Remove the rear light cluster on the left-hand side.
22 Trace the vehicle wiring harness back from the rear light cluster to the lower left-hand corner of the luggage compartment. Peel back the outer covering of the harness sufficiently to attach the cable snap connectors to the relevant wires in the harness.
23 Using the wiring diagrams and with reference to the rear light cluster bulbholder and wiring connector, identify the supply wire for the left-hand rear direction indicator bulb.
24 Using a snap connector, connect the orange wire of the audible warning unit to the direction indicator supply wire of Fiat Punto (see illustration).



Connect the towbar socket and audible warning unit wiring to the vehicle harness using snap connectors


25 Continue this procedure to connect the towbar socket red and black wires to the left-hand stop-light and tail light supply wires respectively.
26 To connect the remaining wires from the Fiat Punto towbar socket and audible warning unit, remove the rear light cluster on the right-hand side.
27 Trace the vehicle wiring harness from the right-hand rear light cluster back towards the left-hand side of the car. Identify the relevant wires in the harness and make the connections using the same procedure as for the left-hand side wiring.
28 When all the connections have been made, attach the audible warning unit to the rear body panel (or a similar location) using foam adhesive pads or similar (see illustration).



Attach the audible warning unit to a suitable place on the rear body panel


29 Check that all connections have been securely made then neatly arrange the wiring. If necessary, use Insulation tape to bind the new wiring to the vehicle harness.
30 Refit the rear light clusters and check the operation of the Fiat Punto towbar socket and audible warning unit. The trailer direction Indicator lights should flash in unison with those on the car, and the audible warning unit should buzz. If the audible warning unit does not buzz, this indicates a bulb failure on the trailer.