Chapter 1 Routine maintenance and servicing
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Chapter 1 Routine maintenance and servicing

Chapter 1 Routine maintenance and servicing Chapter 1 Routine maintenance and servicing

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11.07.2015 Views

1595Ford Fiesta Remake12•4 Body electrical systemswiring diagrams are included at the end of thismanual.2 Before attempting to diagnose an electricalfault, first study the appropriate wiringdiagram, to obtain a complete understandingof the components included in the particularcircuit concerned. The possible sources of afault can be narrowed down by noting if othercomponents related to the circuit areoperating properly. If several components orcircuits fail at one time, the problem is likely tobe related to a shared fuse or earthconnection.3 Electrical problems usually stem fromsimple causes, such as loose or corrodedconnections, a faulty earth connection, ablown fuse, a melted fusible link, or a faultyrelay (refer to Section 3 for details of testingrelays). Visually inspect the condition of allfuses, wires and connections in a problemcircuit before testing the components. Usethe wiring diagrams to determine whichterminal connections will need to be checkedin order to pinpoint the trouble-spot.4 The basic tools required for electrical faultfindinginclude a circuit tester or voltmeter (a12-volt bulb with a set of test leads can alsobe used for certain tests); an ohmmeter (tomeasure resistance and check for continuity);a battery and set of test leads; and a jumperwire, preferably with a circuit breaker or fuseincorporated, which can be used to bypasssuspect wires or electrical components.Before attempting to locate a problem withtest instruments, use the wiring diagram todetermine where to make the connections.Warning: Under nocircumstances may livemeasuring instruments such asohmmeters, voltmeters or a bulband test leads be used to test any of theair bag circuitry or components. Anytesting in these areas must be left to aFord dealer as there is a danger ofactivating the system if the correctprocedures are not followed.5 To find the source of an intermittent wiringfault (usually due to a poor or dirtyconnection, or damaged wiring insulation), a“wiggle” test can be performed on the wiring.This involves wiggling the wiring by hand tosee if the fault occurs as the wiring is moved.It should be possible to narrow down thesource of the fault to a particular section ofwiring. This method of testing can be used inconjunction with any of the tests described inthe following sub-Sections.6 Apart from problems due to poorconnections, two basic types of fault canoccur in an electrical circuit - open-circuit, orshort-circuit.7 Open-circuit faults are caused by a breaksomewhere in the circuit, which preventscurrent from flowing. An open-circuit fault willprevent a component from working.8 Short-circuit faults are caused by a “short”somewhere in the circuit, which allows thecurrent flowing in the circuit to “escape” alongan alternative route, usually to earth. Shortcircuitfaults are normally caused by abreakdown in wiring insulation, which allows afeed wire to touch either another wire, or anearthed component such as the bodyshell. Ashort-circuit fault will normally cause therelevant circuit fuse to blow.Finding an open-circuit9 To check for an open-circuit, connect onelead of a circuit tester or the negative lead of avoltmeter either to the battery negativeterminal or to a known good earth.10 Connect the other lead to a connector inthe circuit being tested, preferably nearest tothe battery or fuse. At this point, batteryvoltage should be present, unless the leadfrom the battery or the fuse itself is faulty(bearing in mind that some circuits are liveonly when the ignition switch is moved to aparticular position).11 Switch on the circuit, then connect thetester lead to the connector nearest the circuitswitch on the component side.12 If voltage is present (indicated either bythe tester bulb lighting or a voltmeter reading,as applicable), this means that the section ofthe circuit between the relevant connectorand the switch is problem-free.13 Continue to check the remainder of thecircuit in the same fashion.14 When a point is reached at which novoltage is present, the problem must liebetween that point and the previous test pointwith voltage. Most problems can be traced toa broken, corroded or loose connection.Finding a short-circuit15 To check for a short-circuit, firstdisconnect the load(s) from the circuit (loadsare the components which draw current froma circuit, such as bulbs, motors, heatingelements, etc).16 Remove the relevant fuse from the circuit,and connect a circuit tester or voltmeter to thefuse connections.17 Switch on the circuit, bearing in mind thatsome circuits are live only when the ignitionswitch is moved to a particular position.18 If voltage is present (indicated either bythe tester bulb lighting or a voltmeter reading,as applicable), this means that there is ashort-circuit.19 If no voltage is present during this test,but the fuse still blows with the load(s)reconnected, this indicates an internal fault inthe load(s).Finding an earth fault20 The battery negative terminal isconnected to “earth” - the metal of theengine/transmission and the vehicle body -and many systems are wired so that they onlyreceive a positive feed, the current returningvia the metal of the car body. This means thatthe component mounting and the body formpart of that circuit. Loose or corrodedmountings can therefore cause a range ofelectrical faults, ranging from total failure of acircuit, to a puzzling partial failure. Inparticular, lights may shine dimly (especiallywhen another circuit sharing the same earthpoint is in operation), motors (eg wipermotors or the radiator cooling fan motor) mayrun slowly, and the operation of one circuitmay have an apparently-unrelated effect onanother. Note that on many vehicles, earthstraps are used between certaincomponents, such as the engine/transmission and the body, usually wherethere is no metal-to-metal contact betweencomponents, due to flexible rubbermountings, etc.21 To check whether a component isproperly earthed, disconnect the battery (referto Chapter 5A, Section 1) and connect onelead of an ohmmeter to a known good earthpoint. Connect the other lead to the wire orearth connection being tested. The resistancereading should be zero; if not, check theconnection as follows.22 If an earth connection is thought to befaulty, dismantle the connection, and cleanboth the bodyshell and the wire terminal (orthe component earth connection matingsurface) back to bare metal. Be careful toremove all traces of dirt and corrosion, thenuse a knife to trim away any paint, so that aclean metal-to-metal joint is made. Onreassembly, tighten the joint fastenerssecurely; if a wire terminal is being refitted,use serrated washers between the terminaland the bodyshell, to ensure a clean andsecure connection. When the connection isremade, prevent the onset of corrosion in thefuture by applying a coat of petroleum jelly orsilicone-based grease, or by spraying on (atregular intervals) a proprietary ignition sealeror a water-dispersant lubricant.3 Fuses and relays -general informationNote: It is important to note that the ignitionswitch and the appropriate electrical circuitmust always be switched off before any of thefuses (or relays) are removed and renewed.1 The main fuse and relay board is locatedbelow the facia panel to the right of thesteering wheel. The fuses can be inspectedand if necessary renewed, by removing thehinged access cover. The remainingadditional fuses and relays (depending onmodel) may be accessed by removing the twofuse board retaining screws, releasing theretaining lugs on either side of the main fuseplate and withdrawing the fuse/relay boarddownwards into the driver’s footwell. Eachfuse location is numbered - refer to the fusechart in the Specifications at the start of thisChapter to check which circuits are protectedby each fuse. Plastic tweezers are attached to

Body electrical systems 12•53.1a Method of fuse/relay board retentionA Retaining screws C SupportB Retaining lugs3.1b Withdrawing the fuse/relay boarddownwards into the driver’s footwellthe inside face of the cover to remove and fitthe fuses (see illustrations).2 To remove a fuse, use the tweezersprovided to pull it out of the holder. Slide thefuse sideways from the tweezers. The wirewithin the fuse is clearly visible, and it will bebroken if the fuse is blown.3 Always renew a fuse with one of anidentical rating. Never renew a fuse more thanonce without tracing the source of the trouble.The fuse rating is stamped on top of the fuse.4 With the exception of the indicator flasherrelay, the remainder of the relays are fitted tothe reverse side of the main fuse/relay board.Access is as described in paragraph 1.5 The various relays can be removed fromtheir respective locations on the fuse board bycarefully pulling them from the sockets.6 The direction indicator flasher relay isattached to the multi-function switch unit onthe steering column. Access to the relay ismade by undoing the retaining screws andremoving the steering column shrouds. Therelay can then be withdrawn from the switch.7 If a system controlled by a relay becomesinoperative and the relay is suspect, listen tothe relay as the circuit is operated. If the relayis functioning, it should be possible to hear itclick as it is energised. If the relay provessatisfactory, the fault lies with thecomponents or wiring of the system. If therelay is not being energised, then it is notreceiving a main supply voltage or a switchingvoltage, or the relay is faulty.4 Switches -removal and refitting2Ignition switch (loom plate andlock barrel)1 Disconnect the battery negative (earth) lead(refer to Chapter 5A, Section 1).2 Remove the manual choke control knob,where fitted, by depressing the lug securing it,and pulling it from its shaft. The lug is foundon the side of the control knob shank.3 Remove the lower steering column shroudby undoing its four retaining screws, thendetach the choke warning light switch/pullcontrol assembly from the lower shroud byunscrewing its retaining collar (bayonet-typefixing), using a suitable tool to locate in thecollar recesses.4 Remove the two screws securing the uppersteering column shroud from above, and thetwo screws securing it from below, the latteraccessible only with the lower shroudremoved.5 Disconnect the ignition switch wiring multiplugconnector. Insert a thin-bladedscrewdriver into the lock tab aperture, releasethe locking tab and remove the loom platefrom its location on the left-hand side of thesteering column.6 Where applicable, undo the single screwand withdraw the Passive Anti-Theft System(PATS) transceiver from the ignitionswitch/steering lock barrel.7 Insert the key and turn the ignition switch toposition ”I”. Depress the lock barrel plungerthrough the steering column lock housing. Asthe lock barrel plunger is depressed, pullon the ignition key to remove the lock barrel(see illustration).8 Refitting is a reversal of the removalprocedure. When relocating the switch to thesteering lock, the barrel driveshaft must align4.7 Withdraw the lock barrel afterdepressing its plunger through theaperture in the steering column lockhousing (arrowed)3.1c Component layout on the fuse/relayboard. See Specifications for relayidentificationwith the switch shaft as it is pushed intoposition. Check the switch for satisfactoryoperation on completion.Steering column multi-functionswitch9 Carry out the operations described inparagraphs 1 to 4 above.10 Disconnect the wiring multi-plugs fromthe multi-function switch assembly, thenremove the single screw securing the switchassembly to the steering column lockhousing. This retaining screw is locateddirectly forward of the hazard warning lightswitch. Remove the switch assembly.11 Refitting is a reversal of the removalprocedure.Facia centre panel switches(below heater controls)12 These switches individually control thefront and rear foglights, heated windscreenand heated rear window element. Wherethese features are not fitted to the vehicle,blanking plates are installed instead ofswitches.13 Disconnect the battery negative (earth)lead (refer to Chapter 5A, Section 1).14 Remove the radio/cassette player asdescribed in Section 22.15 Remove the ashtray, then undo the threescrews from the base of the centre panel.Withdraw the centre panel, disconnecting thecigarette lighter connections as it iswithdrawn.16 Push the required switch/switches outfrom behind, disconnect the multi-plug andremove the switch.17 Refitting is a reversal of the removalprocedure.Centre console switches18 The switches mounted on the centreconsole control the electrically operated121595Ford Fiesta Remake

Body electrical systems 12•53.1a Method of fuse/relay board retentionA Retaining screws C SupportB Retaining lugs3.1b Withdrawing the fuse/relay boarddownwards into the driver’s footwellthe inside face of the cover to remove <strong>and</strong> fitthe fuses (see illustrations).2 To remove a fuse, use the tweezersprovided to pull it out of the holder. Slide thefuse sideways from the tweezers. The wirewithin the fuse is clearly visible, <strong>and</strong> it will bebroken if the fuse is blown.3 Always renew a fuse with one of anidentical rating. Never renew a fuse more thanonce without tracing the source of the trouble.The fuse rating is stamped on top of the fuse.4 With the exception of the indicator flasherrelay, the remainder of the relays are fitted tothe reverse side of the main fuse/relay board.Access is as described in paragraph 1.5 The various relays can be removed fromtheir respective locations on the fuse board bycarefully pulling them from the sockets.6 The direction indicator flasher relay isattached to the multi-function switch unit onthe steering column. Access to the relay ismade by undoing the retaining screws <strong>and</strong>removing the steering column shrouds. Therelay can then be withdrawn from the switch.7 If a system controlled by a relay becomesinoperative <strong>and</strong> the relay is suspect, listen tothe relay as the circuit is operated. If the relayis functioning, it should be possible to hear itclick as it is energised. If the relay provessatisfactory, the fault lies with thecomponents or wiring of the system. If therelay is not being energised, then it is notreceiving a main supply voltage or a switchingvoltage, or the relay is faulty.4 Switches -removal <strong>and</strong> refitting2Ignition switch (loom plate <strong>and</strong>lock barrel)1 Disconnect the battery negative (earth) lead(refer to <strong>Chapter</strong> 5A, Section 1).2 Remove the manual choke control knob,where fitted, by depressing the lug securing it,<strong>and</strong> pulling it from its shaft. The lug is foundon the side of the control knob shank.3 Remove the lower steering column shroudby undoing its four retaining screws, thendetach the choke warning light switch/pullcontrol assembly from the lower shroud byunscrewing its retaining collar (bayonet-typefixing), using a suitable tool to locate in thecollar recesses.4 Remove the two screws securing the uppersteering column shroud from above, <strong>and</strong> thetwo screws securing it from below, the latteraccessible only with the lower shroudremoved.5 Disconnect the ignition switch wiring multiplugconnector. Insert a thin-bladedscrewdriver into the lock tab aperture, releasethe locking tab <strong>and</strong> remove the loom platefrom its location on the left-h<strong>and</strong> side of thesteering column.6 Where applicable, undo the single screw<strong>and</strong> withdraw the Passive Anti-Theft System(PATS) transceiver from the ignitionswitch/steering lock barrel.7 Insert the key <strong>and</strong> turn the ignition switch toposition ”I”. Depress the lock barrel plungerthrough the steering column lock housing. Asthe lock barrel plunger is depressed, pullon the ignition key to remove the lock barrel(see illustration).8 Refitting is a reversal of the removalprocedure. When relocating the switch to thesteering lock, the barrel driveshaft must align4.7 Withdraw the lock barrel afterdepressing its plunger through theaperture in the steering column lockhousing (arrowed)3.1c Component layout on the fuse/relayboard. See Specifications for relayidentificationwith the switch shaft as it is pushed intoposition. Check the switch for satisfactoryoperation on completion.Steering column multi-functionswitch9 Carry out the operations described inparagraphs 1 to 4 above.10 Disconnect the wiring multi-plugs fromthe multi-function switch assembly, thenremove the single screw securing the switchassembly to the steering column lockhousing. This retaining screw is locateddirectly forward of the hazard warning lightswitch. Remove the switch assembly.11 Refitting is a reversal of the removalprocedure.Facia centre panel switches(below heater controls)12 These switches individually control thefront <strong>and</strong> rear foglights, heated windscreen<strong>and</strong> heated rear window element. Wherethese features are not fitted to the vehicle,blanking plates are installed instead ofswitches.13 Disconnect the battery negative (earth)lead (refer to <strong>Chapter</strong> 5A, Section 1).14 Remove the radio/cassette player asdescribed in Section 22.15 Remove the ashtray, then undo the threescrews from the base of the centre panel.Withdraw the centre panel, disconnecting thecigarette lighter connections as it iswithdrawn.16 Push the required switch/switches outfrom behind, disconnect the multi-plug <strong>and</strong>remove the switch.17 Refitting is a reversal of the removalprocedure.Centre console switches18 The switches mounted on the centreconsole control the electrically operated121595Ford Fiesta Remake

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