New Holland T8010 Manual page 1372

Symptom
Engine cranks slowly
Starter motor continues to
operate when key is released
from START to RUN position
Section 55 - Electrical System - Chapter 1
Possible Cause
Starter motor
Engine mechanical problem
Ignition switch.
Starter relay
Intermediate starter relay
Starter solenoid
55-1-191
Reference/Test
F -Starter Motor Test,
test points 3, 4 and 5.
Refer to Engine Section in Service
Manual.
B - Ignition Switch Test, and
confirm that switch turns off when
key is released.
D - Starter Relay Test,
test point 6, and
confirm that relay turns off when
key is released.
E - Intermediate Starter Relay
Test, and
confirm that relay turns off when
the key is released.
F - Starter Motor Test test point 2
and confirm that 12 volts are not
present at terminal 79 when key is
released. If starter continues to run
when 12 volts are removed,
replace starter.