Timer Test; Wing Ice Detection Light Removal - Piper PA-44-180 SEMINOLE Maintenance Manual

OTHER COMPONENTS.
Do not attempt internal repairs of the timer, ammeter or switch. If inoperative, these components must be
replaced with one of the correct part numbers. For any other repair or maintenance problems not covered in this
manual, inquire at Transportation Products Division of the B.F. Goodrich Company, Akron, Ohio 44138.

TIMER TEST.

Field experience indicates that too often the timer is considered at fault when the true trouble lies elsewhere.
Before removing a timer as defective, perform this test:
1. Disconnect wire harness at timer and with deicer switch ON, check voltage from Pin B of harness plug to
ground. If system voltage is not present, the fault is not in the timer. If system voltage is present at Pin B,
check ground circuit using ohmmeter from Pin A to ground. If no circuit is shown, the fault is in ground
lead, not in timer. If ground connection is open, the timer step switch will not change position.
2. When power and ground circuits have been checked, connect a jumper wire from Pin B of harness to B
contact of timer socket to power timer. Connect a jumper wire from Pin A of harness to A contact of timer
socket to complete the power circuit. Now use voltmeter from ground to the timer socket and check that
timer is cycling to deliver system voltage to D and F contacts in that order. Each contact must deliver
voltage for approximately 90 seconds, in turn, and there must be zero voltage on the contact not energized.
3. If the timer meets these requirements, it is not the cause of the trouble. If it fails to perform as indicated, the
trouble does lie in the timer and it should be replaced.
DETECTION.
WING ICE DETECTION LIGHT. (PA-44-180T Only)
This light is used in conjunction with the pneumatic deicing system and will aid the pilot in detecting ice
formation on the left wing leading edge during night flying operations.
The light is mounted in the outboard side of the left nacelle just above leading edge of the wing. It is a sealed
beamed, 12-volt unit, which is controlled from a toggle type switch mounted on the switch panel.
SERVICING.
The only service required of this unit is the replacement of a burned out lamp with a new lamp GE 1383.
REMOVAL. (Refer to Figure 30-14.)
1. Be sure the switch is in the off position.
2. Remove the nacelle access panel in which the light is installed.
3. Remove the screws which secure the socket in the retainer.
4. Pull the socket aft and remove the lamp.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
2F2
3 0 - 8 1 - 0 2
Page 30-46
Revised: May 15, 1989