1997 FIAT PUNTO electrical system wires

3*2 Cooling, heating and ventilation systems
1 General information and precautions
Genera/ Information The engine cooling/cabin heating system is ol pressurised type, comprising a coolant pump driven by the camshaft timing belt (petrol engine models) or auxiliary drlvebelt (diesel engine models), a crossllow radiator, a coolant expansion tank, an electric cooling fan, a thermostat, heater matrix, and all associated hoses and switches. The system functions as follows: Ihe coolant pump circulates cold water around the cylinder block and head passages, and through the Inlet manifold, heater matrix and throttle body to the thermostat housing. When the engine Is cold, the thermostat remains closed and prevents coolant from circulating through the radiator. When the coolant reaches a predetermined temperature, the thermostat opens, and the coolant passes through the top hose to the radiator. As the coolant circulates through the radiator, it is cooled by the in-rush of air when the car is in forward motion. The airllow is supplemented by the action of the electric cooling fan. when necessary, As the temperature of the coolant in the radiator drops, it flows to the bottom of the radiator by convection, and passes out through the bottom hose to the coolant pump - the cycle is then repeatod, When the engine is at normal operating temperature, the coolant expands, and some of It is displaced into the expansion tank. Coolant collects In the tank, and ts returned to Ihe radiator when the system cools. On petrol engine models, the expansion tank is integrated into the side of the radiator. On diesel engine models, and certain petrol engine models with air conditioning, the tank is a separate unit, mounted on the right hand side of the engine compartment. On turbo diesel engine models, the coolant is also passed through a supplementary engine oil cooler, to assist In controlling the engine lubricant temperature. Tho electric cooling fan mounted in front of the radiator is controlled by a thermostatic switch. At a predetermined coolant temperature, the swilch/sensor actuates the tan lo provide additional airflow through the radiator, The switch cuts the electrical supply to the Ion when the coolant temperature has dropped below a preset threshold (see Specifications).
Precautions

A


Warning: Do not attempt to remove the expansion tank pressure cap, or to disturb any part of the cooling system, whlio the engine is hot, as then is a high risk of scalding, tf the expansion tank pressure cap must be removed before the
engine and radiator have fulty cooled (even though this is not recommended?, the pressure in the cooling system must first be relieved. Cover the cap with a thick layer of cloth, to avoid scalding, and slowly unscrew the pressuro cap until a hissing sound Is heard. When the hissing stops, indicating that the pressure has reduced, slowly unscrew the pressure cap until it can be removed; If more hissing sounds are heard, wait until they have stopped before unscrewing the cap completely. At all times, keep your face well away from the pressure cap opening, and protect your hands.

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Warning: Do not allow antifreeze to come into contact with your skin, or with the painted surfaces of the vehicle. Rinse off spills immediately, with plenty of water. Never leave antifreeze lying around in an open container, or In a puddle In the driveway or on the garage floor. Children and pets are attracted by its sweet smell, but antifreeze can be fatal tf ingested.

A


Warning: If the engine is hot, the electric cooling fan may start rotating even if the engine and ignition are switched off. Be careful to keep your hands, hair, and any loose clothing well clear when working In the engine compartment.
2 Cooling system hoses - f&> disconnection and renewal ^
1 The number, routing and pattern of hoses will vary according to model, but the same basic procedure applies. Before commencing work, make sure that the new hoses are to hand, along wilh new hose clips if needed, it is good practice to renew the hose clips at the same time as the hoses. 2 Drain the cooling system, as described in Chapter 1A or 18, saving the coolant if it is fit for re-use. Apply a little penetrating oil onto the hose clips if they are corroded. 3 Release the hose clips from the hose concerned. Three types of clip are used; worm-drive. spring and 'sardine-can'. The worm-drive clip is released by turning its screw anti-clockwise. The spring clip Is released by squeezing Its tags together with pliers, at the same time working the cbp away from the hose stub. The sardine-can clips are not re-usable, and are best cut off with snips or side cutters. 4 Unclip any wires, cables or other hoses which may be attached to the hose being removed. Make notes for reference when reassembling If necessary. 5 Release the hose from its stubs with a twisting motion. Be careful not to damage the stubs on deltcate components such as the radiator, or thermostat housings. If the hose Is stuck fast, the best course is often to cut it off using a sharp knife, but again be careful not to damage the stubs.
6 Before fitting the new hose, smear the stubs with washing-up liquid or a suitable rubber lubricant to aid fitting. Do not use oil or grease, which may attack the rubber. 7 Fit the hose clips over the ends of the hose, then fit the hose over its stubs. Work the hose Into position. When satisfied, locate and tighten the hose dips. 6 Refill the cooling system as described In Chapter 1A or 1B. Run the engine, and chock that there are no leaks. 9 Recheck the tightness of Ihe hose clips on any new hoses after a few hundred miles. 10 Top-up the coolant level if necessary.
3 Radiator -
removal,
inspection and refitting
Removal Note: If leakage is the reason for removing
the
radiator, bear In mind that minor leaks can often be cured using proprietary radiator sealing compound, with the radiator in situ. 1 Disconnect the battery negative terminal (refer to Disconnecting the battery In the Reference Section of this manual). On diesel engine models, unbolt the relay bracket from the side of the battery tray. 2 Drain the cooling system as described In Chapter 1A or 1B. 3 On 1242 cc (16-valve) petrol engine models, remove the air cleaner and Inlet ducts as desenbed In Chapter 4B, 4 Slacken the clips and disconnect Ihe (op and bottom coolant hoses from the radiator. In addition on diesel engine models, and petrol engine models with a remotely-sited expansion tank, disconnect the expansion tank coolant hose from the right hand side ol the radiator (see Illustrations), 5 Unscrew the fixings and lift the plastic trim panel from above the front bumper Unscrew the bolt(s) securing tho radiator to the upper body panel (see Illustration). Note that the radiator and cooling fan assembly share the same upper mounting bolt. 6 Unbolt the cooling fan(e) and shroud assembly from Ihe rear ot the radiator, as described in Section 5.
3.4a Slacken the clip and disconnect the radiator bottom hose

5C«2 Preheating system - diesel models
2.3 No 4 glow plug showing the main supply lead end the interconnecting strap 2.5 Removing a glow plug
2 Glow plugs -removal, Inspection and refitting
Removal Caution: If the preheating system has just been energised, or If tho engine has been running, the glow plugs will be very hot
1 Disconnect the battery negative terminal (refer to Disconnecting the battery in the Reference Section of this manual), 2 Remove Ihe air Inlet ducting from the front of the engine with reference to Chapter 4C, Section 2. 3 Unscrew the nut from the relevant glow plug lerminai(s). and recover the washer(s). Note that tho main supply cable is connected to Number 4 cylinder glow plug and an interconnecting strap lis fitted between the four plugs (see Illustration). 4 Where applicable, carefully move any obstructing pipes or wires lo one side to enable access to the relevant glow plug(s). 5 Unscrew the glow plug(s) and remove from the cylinder head (see illustration).
Inspection 8 Inspect each glow plug for physical damage. Burnt or eroded glow plug tips can bo caused by a bad Injector spray pattern. Have the Injectors checked if this sort of damage is found. 7 If Ihe glow plugs are In good physical condition, check them electrically using a 12 volt test lamp or continuity tester as described in the previous Section. 8 The glow plugs can be energised by applying 12 volts to them to verity that they heat up evenly and In the required time. Observe the following precautions. a) Support the glow plug by clamping it carefully in a vice or selNocking pliers. Remember it will become red-hot. b) Make sura that the power supply or test lead incorporates a fuse or overload trip to protect against damage from a short-circuit. c) After testing, allow the glow plug to cool for several minutes before attempting to handle it. 9 A glow plug In good condition will start to glow red at the tip after drawing current for 5 seconds or so. Any plug which takes much longer to start glowing, or which starts
glowing in the middle instead of at the lip, « defective. Refitting 10 Refit by reversing the removal operations. Apply a smear of copper-based anti-seize compound to the plug threads and tighten Ihe glow plugs to Ihe specified torque. Do not overtighten, as this can damage the glow plug element.
3 Preheating system control unit -removal
and
refitting I
Removal 1 Disconnect the battery negative terminal (refer to Disconnecting the baffery In Ihe Reference Section of this manual). 2 Unscrew the screws and remove the relay cover located at the left-hand end of the engine. 3 Disconnect the wiring then remove the control unit from the bracket. Refitting 4 Refitting is a reversal of removal.

12*2 Body electrical systems
3 Electrical problems usually stem from simple causes, such as loose or corroded connections, a faulty earth connection, a blown fuse, a melted lusible link, or a fautty relay {refer to Section 3 for details of testing relays). Visually inspect the condition of all (uses, wires and connections in a problem circuit before testing the components. Use the wiring diagrams lo determine which terminal connections will need to be checked, in order to pinpoint the trouble-spot. 4 The basic tools required for electrical fault-finding include a circuit tester or voltmeter (a 12-volt bulb with a set of lest leads can also be used for certain tests}; a self-powered test light (sometimes known as a continuity tester); an ohmmeter (to measure resistance): a battery and set of tesi leads: and a lumper wire, preferably with u circuit breaker or fuse incorporated, which can be used to bypass susoect wires or electrical components. Before attempting to locate a problem with tost instruments, use the wiring diagram to determine where to make the connections. 5 To find the source of an intermittent wiring fault (usually due to a poor or dirty connection, or damaged wiring Insulation), a wiggle test can be performed on the wiring. This involves wiggling the wiring by hand, to see if tha fault occurs as the wiring Is moved. It should be possible to narrow down the source of the fault to a particular section of wiring. This method of testing can be used in conjunction with any of the tests descnbed in the following sub-Sections. 6 Apart from problems due to poor connections, two basic types of fault can occur in an electrical circuit - open-circuit, or short-circuit. 7 Open-circuit faults are caused by a break somewhere in the circuit, which prevents current from flowing. An open-circuit fault will prevent a component from working, but will not cause the relevant circuit fuse to blow 8 Short-circuit faults are caused by a shod somewhere in the circuit, which allows Die current flowing In the circuit to escape along an alternative route, usually to earth. Short-circuit faults are normally caused by a breakdown in wiring insulation, which allows a feed wire to touch either another wire, or an earthed component such as the bodysheli. A short-circuit fault will normally cause the relevant circuit fuse to blow.
Finding an open-circuit 9 To check for an opon-circuit, connect one lead of a circuit tester or voltmoter to either the negative battery terminal or a known good earth. 10 Connect the other lead to a connector in the circuit being tested, preferably nearest to the batter/ or luse. 11 Switch on the circuit, bearing In mind that some circuits are live only when tho ignition switch is moved to a particular position. 12 If voltage is present (Indicated either by
3.2 Main fuse box, located on the driver's side of the facie the toster bulb lighting or a voltmeter reading, as applicable), this means that tho section of Ihe circuit between the relevant connector and the battery is problem-free. 13 Continue to check the remainder ot the circuit in the same fashion. 14 When a point is reached at which no voltage Is present, the problem must lie between that point and the previous test point with voltage. Most problems can be traced to a broken, corroded or loose connection.
Finding a short-circuit 15 To check for a short-circuit, first disconnect the load(s) from the circuit (loads are the components which draw current from a circuit, such as bulbs, motors, heating elements, etc). 16 Remove the relevant luse Irom the circuit, and connect a circuit tester or voltmeter to the luse connections. 17 Switch on the circuit, beanng in mind that some circuits are live only when the ignition switch is moved to a particular position. 18 If voltage is present (indicated either by the tester bulb lighting or a voltmeter reading, as applicable), this means that there Is a short-circuit. 19 If no voltage is present, but the fuse still blows with the load(s) connected, this indicates an internal fault in the load(s).
Finding an earth fault 20 The battery negative terminal Is connected to 'earth' - the metal of the engine/transmission and the car body - and
I
IK
J 3.3 To gain access to the fuses, remove the screw and pull the stowage bin away from the facia
most systems are wired so that they only receive a positive feed, the current returning via the metal of Ihe car body. This means that the component mounting and the body form part of that circuit. Loose or corroded mountings can therefore cause a range of electrical faults, ranging from total failure ot a circuit, to a puzzling partial fault. In particular, lights may shine dimly (especially when another circuit sharing the same earth port In operation), motors (eg wiper motors v Ihe radiator cooling fan motor) may run slowly, and Ihe operation of one circuit may have an apparently-unrelated effect on another. Ncie that on many vehicles, earth straps axe uses between certain components, such as the engine/transmission and the body, usually whore there is no metal-to-metal contact between components, due to flexible rubber mountings, etc. 21 To check whether a component $ properly earthed, disconnect Ihe battery, and connect one lead of an ohmmeter to a kwwi good earth point. Connect the other lead to the wire or earth connection being tested. Tha resistance reading should be zero; if not. check the connection as follows. 22 If an earth connection Is thought to be faulty, dismantle the connection, and clean pack to bare metal both the bodysheli and ite wire terminal or the component earth connection mating surface. Be careful to remove all traces of dirt and corrosion, then use a knife to trim away any palm, so thai a clean metal-to-metal joint Is mads. On reassemoly, tighten the joint fasteners securely: if a wire terminal Is being refitted, use serrated washers between tho terminal and the bodysheli. to ensure a clean and secure connection. When the connection is remade, prevent the onset ot corrosion in the future by applying a coat of petroleum idly
or
stlicone-based grease, or by spraying on (a: regular intervals} a proprietary ignition eoater, or a water-aispersant lubneant.
3 Fuses and relays -general information
Fuses 1 Fuses are designod to break a circuit when a predetermined current is reached, in order to protect the components and wiring wttioh could be damaged by excessive current How. Any excessive current flow will be due to a fault in the circuit, usually a short-circuit (see Section 2). 2 The main fuses are located in the fusefcox on the driver's side of the facia (see illustration). 3 To gain access to the fuses, remove tne screw and pull the stowage bin moulding away from the facia (see illustration). 4 Additional fuses and circuit-breakers are located In the engine compartment, and in an