Husqvarna 520iHE3, Workshop Manual

Page: 18 / 59

18 – English
Diagnosis and troubleshooting
1 2 3 4 5 6
M1
B-
B+
B-
M
5.4 Troubleshooting the main switch
For products with S/N: -20180400173 (LiHE3).
The switch used in professional battery products
from Husqvarna has two functions, to supply cur-
rent to the control unit and the electric motor, and
act as a position sensor for the variable speed
control. All these functions can easily be tested and
verified using a resistance meter.
Note: The switch should not be depressed more
than 6 mm and not to its end position when
testing.
• Measure between B+ and B- when the switch is
not depressed. The result should be open circuit.
• Measure between B+ and B- when the switch is
depressed. The result should be closed circuit.
• Measure between pin 2 and pin 5 when the
switch is not depressed. The result should be
closed circuit.
• Measure between pin 2 and pin 5 when the switch
is depressed. The result should be 50 kΩ ± 25 %.
• Measure between B- and Pin 1. The result should
always be closed circuit.
If all readings are within specified limits, the switch
is OK.
For products with S/N: 20180400173- (LiHE3).
Use the Common Service Tool to check the func-
tionality of the main switch.