Flame heater fuel pump electrical system is negative
g r o u n d e d . P i n A is positive and pin B is negative. Do
n o t switch polarity of pump during checking or replace-
m e n t . C h a n g i n g polarity will permanently damage pump.
H o o k up 24-volt battery (1) with rheostat (2) to fuel pump receptacle (3).
H o o k up voltmeter (4) to fuel pump receptacle (3).
GO TO FRAME 4