Hummer H1 Service Manual page 819

12-48 Electrical System
Fuel Tank Selector System Inoperative (No Tank Switch)
Step
7 Relocate the ground lead of the DVOM set to
measure voltage to a known good ground. Turn
the ignition OFF for 10 seconds. Turn the ignition
ON, and the tank selector switch in the AUX posi-
tion, probe the brown wire (CKT 789) with the
positive meter lead. Is voltage present?
8 Turn the ignition OFF for 10 seconds. Turn the
ignition ON, and the tank selector switch in the
MAIN position, probe the red wire (CKT 786)
with the positive meter lead, the ground lead
should be on a know good ground. Is voltage
present?
4-1-00
_______________________________________________________
Action Value(s) Yes
12 v Go to step 8.
12 v No electrical
problems found,
problem may be
intermittent or
mechanical.
®
No
Repair open,
bad connection
or short to
ground in CKT
789 between the
fuel selector
switch and
valve.
Repair open,
bad connection
or short to
ground in CKT
786.