PIPER SENECA II SERVICE MANUAL
01/01/09 XIV - ACCESSORIES AND UTILITIES
3A11
14-7. USING THE AMMETER.
Whether in flight or during ground testing, the ammeter can be used to indicate the general nature of
most electrical problems. The troubleshooting chart is primarily based on this use of the ammeter and
assumes that the user does understand all normal operating modes of the system as given in Paragraph
14-4.
NO
TE: When troubleshooting, first use the “ammeter test” and “heat test” to determine which circuits
are involved. Use circuit diagram, Figure 14-8, for assistance to check voltages or continuity.
14-8. HELPFUL TIPS.
a. If the ammeter reading drops to one-third normal current, this indicates that one heater circuit is
open or, on the dual element deicer, possibly improper connections are allowing both inboard and
outboard units to heat at the same time.
b. Excess current reading on the ammeter always indicates a power lead is shorted to ground. Thus,
when trouble of this nature is found, it is vital that the grounded power lead be located and
corrected.
c. A considerable number of timers that have been returned for repair proved to be fully workable
when tested. Accomplish the test described in Paragraph 14-33 before concluding that the timer is
defective.
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