1. Part 1: Vehicle Information
Studentname(s):
EfrainGonzalezandJustinSerr
Vehicle year,make,model:
1994 Ford Ranger
Customer’s name &repairordernumber:
DenisTaylor
Customer’sconcern(s):
Headlampswitchisnotworking properlyandneedstobe replaced.Youhave toplaywithit a lotin orderto get the
headlightstoturnon andoff.The headlights,taillights,anddashlightwill notall turnonat the same time.
Part 2: Documentation
Documentthe stepsyoutookto diagnose andrepairthe vehicle—inthe orderthatyoudidthem. Write every
step—evenif you made mistakesand nowwishyouwouldhave done itdifferently. Beginwhenyoupickedupthe
keys,endwhenyoureturnedthem. BEDETAILED & INCLUDE PHOTOGRAPHS!
1. We pickedupthe keys to the 1994 Ford Rangerfromthe office at Austin106 at BYU-Idaho.We drove it to
the Agriculture Engineeringbuildingandparked itinside the lab.
2. We startedbyplayingwiththe headlampswitchtoverifythe customer’sconcern.

2. 3. We confirmedthatthe headlights,taillights,anddashlightwere notall turningonat the same time. The
taillightswouldnotturnon at the same time as the headlights,sometimesthe dashlightwouldturnonat
the same as the taillights,andthe dash lightwouldnotturnon at the same time asthe headlights.
4. We turnedthe headlightsonand noticedthatthe right headlightbulbwasnotworkingandonlythe left
headlightbulbwaslightingup.
5. We turnedthe switchtoturn on the highbeamlightsonand noticedthatthe highbeamlightswere not
working.
6. As we were doingavisual inspection,we noticedthatthe batteryhadsome corrosiononthe terminals.
7. We wentonline ontoProDemandtolookupa wiringdiagramfor the headlampscircuitand alsoto see if we
couldfindanyTSB’s on thiskindof problem.
8. We putour vehicle’sinformationintoProDemandandstartedtolookup wiringdiagramstofindone forthe
headlamps.
9. We found a wiringdiagramforthe headlampscircuitandprintedit.
10. We lookedforTSB’son problemswiththe headlampswitchonProDemandandGoogle butwere notable to
findany.
11. We studiedthe wiringdiagramforthe headlampscircuitandstartedtoformulate aplanto diagnose the
circuit.
12. Our planwas to visuallyinspectthe headlightbulbthatwasnotlightingup,checkthe powerand ground
cablesforthe bulb,andworkour wayup the diagram.

3. 13. We pulledoutourmultimeter,setittomeasure voltage drop,connectedourleadstothe batteryterminals,
and checkedforthe battery’s state of charge.The multimeterread12.36 volts.We deemedthe state of
charge as close enoughto75 percent.
14. We thenpulledthe headlightbulbthatwasnot lightingupoutto checkit forvoltage dropand,as soonas
we pulleditout,itlitup.
15. We were confusedbythe bulb’sintermittentproblembutproceededtocheckitforvoltage drop.
16. The wiringdiagramfor the headlampscircuitindicatedthatthe wire forpowerwasredwitha black tracer
and the wire forgroundwas black.
17. We stucka T-pininthe back of the of the bulb’sterminals,alongthe powerandgroundwires,tocheckfor
voltage drop.
18. We setour multimeterto measure voltage dropandconnectedourleadstothe T-pinsback-probingthe
bulb’sterminals.The multimeterread11.56 volts.We determinedthatitwasdroppingmostof the volts.
19. We tookthe leadoff the T-pinalongthe ground wire andconnecteditto the battery’snegative terminalto
measure voltage droponthe groundside of the circuit.The multimeterread4 millivolts,whichequalsoutto
.004 volts.
20. We tookthe leadoff the T-pinalongthe powerwire andconnecteditto the T-pinalongthe ground wire,
and we tookthe leadon the battery’snegative terminal andputiton the positive terminal tomeasure
voltage dropon the powerside of the circuit.The multimeterread577 millivolts,whichequalsoutto.577
volts.
21. We determinedthatthere wasresistance inboththe powerandgroundwiresbutnothingoutof the
ordinarybutwe decidedtoservice the batteryandmake sure thatthe corrosionon it wasnot creatingany
resistance.
22. We pulledthe batteryout,cleanedthe terminals,cables,andthe batteryitself.Whenwe pulledthe battery
out,we noticedthat there wasa huge pile of batteryacidunderneaththe battery.We cleaneditoutandput
the batteryback in.We sprayedthe terminalswithachemical thatpreventscorrosionandhooked
everythingbackup.

4. 23. We wentbackto the lightbulbthatkeptturningoff andon. Aswe were workingaroundthe bulbwe
noticedthatit wasgettingextremelyhot.Itwouldinstantlymeltourglovesassoonaswe made contact
withit.
24. We noticedthatthe bulbwasmeltingitsconnectorandthat it was most likelybecause the blubwas
creatingtoo muchresistance.
25. We determinedthatthe bulbwasnotsupposedtobe gettingthat hotand that itneededtobe replaced.

5. 26. We wentonline onto MitchellManagerandordereda new setof high/low beamheadlightbulbsfromNapa
AutoParts for a 1994 Ford Ranger2.3 L.
27. We receivedthe bulbsfromNapaAutoPartsandrecordedthe invoice onMitchell Manager. We put the
invoice withourname andrepairordernumberinthe invoice box.
28. We tookbothheadlightbulbsoutand replacedthemwiththe new setof bulbs.
29. Aftertakingthemout,we noticedthatthe leftheadlightbulbwasdifferentthanthe rightheadlightbulband
determinedthatthatwas the cause for the highbeamlightsnotworking.

6. 30. We usedthe switchtoturn the headlightson,andthe highbeamlightson,and we confirmedthatreplacing
the bulbswasthe correct repairforthat problem.
31. We calledthe customer,DennisTaylor,toupdate himonhow the repairon hisvehicle wasgoing. He
mentionedthe problemwiththe taillightsonce more.He saidthatthe switchwouldonlyallow youtoeither
have the taillightsonorthe headlightsonbutnot bothon at the same time.
32. We playedwiththe switchonce more andconfirmedthatthe problemwasstill there.
33. We decidedtodoa batterysystemtestand a handheldtestto getthat checkedoff our labsheet.
34. The batteryfailedbothtests sowe inspectedthe batterymore closely.
35. We noticedthatthe batterywas leakingfromthe bottom.

7. 36. We proceededtomake aplan to diagnose the headlampswitch.
37. We wentonline ontoProDemandtofindawiringdiagramforthe headlampswitchcircuit.
38. We made a secondplan usingthe headlampswitchwiringdiagram.
39. Basedoff the problems,we decidedtostartat the switchitself andmove ourwaytowardswherever the
switchpointedus,powerorground.
40. We wentbackto ProDemandandprintedoff the removal stepsforthe headlampswitch.
41. We thenproceededbypullingthe dashapartand removingthe switchasinstructed.
42. At thistime classwasoverso we wentto pull the truck outand it wouldn’tstartevenwiththe assistance of
the boosterpack.
43. So we pushedthe truckout and decidedtolookmore into itduringthe nextlab.
44. We decidedwe were goingtofinishfixingthe taillightsandthenfindoutwhyitwouldn’tstart.

8. 45. Nowthat we had the headlampswitchoutwe testeditwhile inthe onposition, where all the lightsshould
have beenworkingtogether.First, we testedthe powerforthe taillightswhichwere notworking.Nopower
was cominginon the taillightside.
46. Next,we checkedthe powerandgroundforthe headlightportionof the switch,we foundthatthere was
powergettingtothe headlightportion.
47. We decidedtouse jumperwirestogofromthe poweronthe headlightside tothe taillightside tosee if they
wouldturnon. Theydidturn onwhenwe usedthe jumperwires.
48. We determinedthatthe problemwas notinthe switchand wason the powerside sowe decidedtogo the
fuse next.
49. We checkedthe fuse anditwas blown.
50. We replacedthe fuse andthe taillightsworked.
51. We thenplayedwiththe wiresandthe switchtosee if we couldgetthe fuse to blow againand we could
not.
52. While workingonthe switchwe noticedthe turnsignals wouldnotworkaswell.Notall the bulbswere
lightingproperly.Butwhenwe turnedon the hazards,all the bulbslitupperfectly.
53. We checkedthe fusessince we were alreadythere andbecause we wonderedif theywere related.
54. The fuse for the turn signalswasnotgettingpowerandwasnot blown.
55. But classwas almostoverso we decidedtowaitonthe turn signalsandsee if we couldget the truck to start.
56. We talkedaboutourcollectionof smallerproblemsand how the truckwould notstart and decidedwe
wouldstartby pullingthe batteryoutagainbutthistime we would replaceditwithaboosterpack to see if
all the componentswouldworkanybetterand see if the truck would start.

9. 57. The truck startedright up andthe blinkers anddashlightsworkedperfectly.
58. We determinedthatthe batterywasnotworkingproperlyandwasmost likelysacrificingcertainelectrical
componentsbecause itwasnotproducingthe correct amountof voltage.
59. We decidedtoreplace the battery.
60. We calledthe customer,DennisTaylor,tomake sure he wasokaywithus purchasinga new battery.He
approvedthe purchase.
61. We calledNapaAutoPartsand ordereda new batteryfora 1994 FordRanger 2.3 L.
62. Whenwe got the battery,we returnedthe core and turnedinour invoice withourname andrepairorder
numberintothe invoice box.
63. We replacedthe oldbatterywiththe new one andtested all the electrical componentstomake sure the
replacingthe batterywasthe correct repair.
64. Everythingworkedthe wayitshould.All the problemsdisappeared.
65. We putthe headlampswitchbackinandput the dash back together.

10. 66. Thenwe took the truck for a shorttest drive tosee if the fuse wouldblow againanditdidnot.
67. We thencalled the customer, DenisTaylor, tolethimknow where we were atandthat hisvehicle was
ready.
68. We confirmedthathe couldcome getit and lethimknow where we were parkingit.
69. Lastly,we parkedthe truck and gave the keysand the repairordersheettothe office inAustin106 at BYU-
Idaho.
Part 3: Reflection & Analysis
 What parts of thisprocesswentwell?
We workedgreatas a teamand were able tothinkthingsthroughand figure outhow to make a plan to diagnose
the problem.We dida goodjob at takingthe skillswe learnedinclass, aboutcircuitsandelectricity,andputthem
intoa real worldapplication.Ourabilitytoread,understand,andinterpretthe wiringdiagramswascrucial tothe
whole processof repairingthe vehicle.We were able tosuccessfullydiagnose the problem, perform, andconfirm
the repairbecause we followedthe correctstepstodiagnose,andrepairthe vehicle (the7steps).
 Whichstepswere mostcritical inyour diagnosisprocess?

11. The most crucial stepsinour diagnosisprocesswasourstudyingof the componentsandourplanningtodiagnose
the problemswiththem. We wentbackto those stepsrepeatedly,whichgrantedusthe mostsuccess.Everytime
we wentback to re-studyandre-planwe learnedandgotbetterat it.
 What keptyoufrom beingaseffectiveasyoucouldhave been?
We hada fewsetbacksinrepairingthe vehicle.One of those beingourplanning.Because of lackof experience,we
didnot reallyknowwhere tostart or where toend.We followedthe 7stepsbut notas effectivelyandcorrectlyas
we couldhave. We were alsoveryunexperiencedusing ProDemandandMitchel manager,whichsignificantly
slowedusdown.The lackof experience wasprobablyourbiggestproblem repairingthisvehicle.
 Nowthat youcan lookbackon howthisprojectunfolded,whatwouldyouliketododifferentlynexttime?
We wouldhave beenmore thoroughinthe 7 steps,especiallyinourvisual inspectionof the vehicle andinour
planning.If we were tohave beenthoroughinourvisual inspection,we wouldhave noticedthatthe battery didnot
lookso good,wouldhave proceededtotestingit,andwouldhave foundoutthatit wasbad. If we were to have
done this,we wouldnothave dealtwithrollingituphill andthinkingwe didsomethingwrongwhenthe vehicle did
not start that one labday. Our planningwasmore of an ideaof whatwe were goingto do ratherthan a stepby step
process. If we wouldhave beenmore thoroughinourplanning,thenwe wouldhave nothadtore-plansomuch. We
spenta lotof time walkingfromourvehicle tothe computersandbackto our vehicle again.If ourplanningwould
have beenbetter,the projectwouldhave takenusaslongas itdid.