A. Windows,Windshieldsand Doors
1. Heated Windshield
(a) FunctionCheck
The following stepsdetermineif windshield heatingelementand timer are functioningproperly:
(1.) Connect24-volttest light to positive and negativeterminalsof windshield.
(2.) Setswitch marked Windshield Heatto ON position. Testlightmustindicatecurrentbeing

deliveredto windshield. (3.) Placehandagainstwindshieldto determineif windshield heatingelementis operating. (4.) Ensuretest light extinguishes beforewindshieldis too hot to hold hand againstit. This
indicatesthat temperature sensingelementisoperating properly and has passedthrough thermostaticon-off cycle.
CAUTION:  USECAUTIONDURINGGROUNDOPERATIONTO PREVENT OVERHEATINGAND POSSIBLEDAMAGETO WINDSHIELD.
(5.) After completing check,set WindshieldHeatto OFF position. Removetest light. (6.) See 56-00-00 for additionalservicedata.
(b) Copilot'sHeatedWindshield
Windshieldis identical to pilot sideand is serviced like standardleftwindshield.
2. Windshield Wiper Mechanism

Windshieldwipersarestandardequipmenton left and rightwindshield. Tooperatewindshield wipers,turn switchon lower rightsideof instrumentpanelto HIGH or LOWposition. Whenturning wipersoff, turn switchto OFFor PARK position. The OFFpositionstopsbladesin place while PARKpositionreturnsbladesto center postposition.
WARNING: NEVER OPERATE WINDSHIELDWIPERON DRY WINDSHIELD. IT CAN SCRATCHGLASSANDSHORTENLIFEOF WIPER BLADES.
Thewindshieldwiper motoris located forwardof bulkheadat Station 57.00,on upperleftportionof fuselageskin. A flexible shaftrunsfromelectricmotorandtransmissionto a converter (fromwhich wiperruns) on right side of same bulkhead.
(a) Removalof WiperMechanism(Figure401)
(1.) Removeaccesspanelon leftand right sides of nose section.
(2.) Cut lockwireat bolt securingarmto serrated convertershaftand removebolt.
(3.) Loosenadjustmentnut. Lift wiper arm off convertershaft.
(4.) Removetwo screwsfrom shaft coveraroundconvertershaft. Removecoverandold

sealantfrom shaft. (5.) Disconnectelectricalconnectionto wiper motor and flexibledriveshaftfrom converter. (6.) Removeremainingscrewsholdingmotorand converter to airplane. Removecomplete assembly.
EFFECTIVITY:
040-999  30-40-00 PAGE
Jan 10/90

PIPERAIRCRAFT
PA42-720 (Advanced Trainer)
MAINTENANCE MANUAL

A. Windows,WindshieldsandDoors (continued)
2. WindshieldWiper Mechanism (continued)
(b) Installationof Wiper Mechanism (Figure 401)
(1.) Timewiper motor and converter before connecting two units together, as follows: (a.) Rotate drive shaft in converters to end of travel (or park position) and at serrated convertershaft. (b.) Temporarily connectelectricalconnectorto wiper motor and operate motor until switch ends in PARK position. Disconnect electricalconnector.
(2.) Assemble wiper motor and converter by screwing units together with flexible drive assembly;back off for bracket alignment.
(3.) Assemble units slowly until flexible drive assembly engagesconvertershaft. Alignment must be automatic. If severe binding occurs, back off and reassemble.
(4.) Install assembled units into airplane and secure to mounting brackets. Do not install seal coversat this time.
(5.) Apply bead of RTV sealer around convertershafts extending through fuselage. Position and secure shaft cover in place with retaining screws.
(6.) Connect electricalconnectorto wiper motor and replace accesspanels. Turn wiper switch momentarilyto PARK position.
(c) Wiper Blade and Arm Removal (Figure 401)
(1.) Cut lockwireat bolt securing arm to serrated convertershaft; remove bolt.
(2.) Loosen adjustment nut to relieve arm tension. Remove wiper arm from converter shaft.
(3.) Pull out lock on wiper blade to remove blade from arm assembly.
(d)Wiper Blade and Arm Installation (Figure 401)
(1.) Install wiper blade to assembly. Ensure blade is locked to arm.
(2.) Turn wiper switch momentarily to PARK position. Place arm and blade assembly on serratedconvertershaftso wiper blade clears windshield centerpost centerline by approximately2.00 to 2.25 inches.
(3.) Install bolt through wiper arm into converter shaft.Tighten and safety with MS20995-C41
lockwire.
(e)Wiper Blade and Arm Adjustment (Figure 401)
(1.) Adjust wiper blade height on windshield byunlockingblade height adjustment cam. (2.) Adjust blade height on windshield so bottom of blade clears windshield collar by 2.50 ±
0.50inches.Lock adjustment cam. (3.) Adjust wiper blade angle by loosening nut on wiper blade attachment stud. Rotate blade until it is parallel with windshield center post. Tighten nut on stud.
(4.) Adjust nut on wiper arm adjustment stud for tension of 3 -4 pounds with blade pivot point in PARK position.
　
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