911 Carrera Coupe F6-3164cc 3.2L (1984)
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Set ammeter to 10 amp range and connect leads in series between battery minus and body ground point before disconnecting battery minus pole.
The ammeter is used for current flow without interruption. Disconnect battery minus cable at battery and observe ammeter. If no display, switch
ammeter to mA range without disconnecting leads. Measuring current draw in this manner will prevent possible sticking relays or other circuits
from opening.
Waiting times:
911 Carrera 2/4 from 1989 (K) and 911 Turbo from 1991 (M): 20 minutes (climate control)
928 S4, GT, GTS: 45 minutes (cooling fan control, instrument cluster, power window /sunroof control unit)
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Maximum current draw for all models: 30 mA. If constant current draw is above 30 mA, the cause must be determined. Pull fuses and relays one at
a time from the central electric board with the ammeter connected. Observe the ammeter for current drop.
Locate consumer with high current draw. Check for the presence of aftermarket electrical equipment and disconnect as necessary. If current draw is
within specifications and additional current draw from aftermarket equipment results in higher than specified values, the customer/owner must be
notified in writing on the Repair Order of the potential for increased battery discharge caused by said equipment. Battery discharge caused by
aftermarket equipment is not a warranty matter.
Important:
Carrera 2/4 and 928 S4/GT The current draw is higher (maximum 1 amp) for a short while after connecting or switching the ammeter.
This is caused by the instrument cluster and fan control unit on 928 vehicles and the climate control unit on 911 Carrera 2/4 vehicles. Use a testing
device with a fused range up to 4 amps. It should be possible to switch the tester to a 40 mA range without current interruption.
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When assuming a sticky relay may be the problem, proceed as follows: To avoid opening of the relay, connect ammeter to battery minus and body
ground point before disconnecting battery minus pole. The ammeter is used for current flow without interruption. Disconnect battery cable and
observe ammeter.
9. Summary
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Check battery voltage or electrolyte density when receiving new vehicles.
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Before vehicle delivery, check battery voltage or electrolyte density and starting capability. Same applies to new batteries before installation.
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Vehicles in storage and filled spare batteries:
Check battery voltage or electrolyte density periodically. Recharge if necessary. This does not apply to dry batteries until filled with electrolyte.
Observe dry battery shelf life (24 month).
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Demo and showroom vehicles: Periodical preservation charging.
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Perform a battery service prior to a long parking/storage period (charging, electrolyte level, voltage test). Periodical preservation/maintenance
charging.
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Before checking battery voltage observe battery rest times. Do not load the battery prior to checking voltage.
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Recharge discharged batteries immediately. Do not fast charge batteries. Determine cause for discharge.
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Use only Porsche approved batteries.
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Use digital measuring devices to check voltage and current draw. (Display accuracy.)
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Measured device for current draw should have a fused 4A range.
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When checking battery voltage, compensate for battery temperature (correction values for voltage and electrolyte density).
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Danger of explosion when connecting or disconnecting battery cables.
