CHECKING GAUGES

ELECTRICAL

If the receiver does not operate

One new fuel tank sending unit. If there is

correctly, then check the wire lead to the

any question about the new tank unit being correct, then

receiver unit.

hook it up in series with a receiver unit known to be

satisfactory. Operate tank unit by hand and see if

(1) Attach one end of the ten foot

receive unit reads zero with tank unit float in bottom

length of wire to the terminal of the

position.

receiver unit to which the wire lead is

attached.

Two 5 foot lengths of insulated wire

equipped with clip terminals at each end. These long

(2) Ground the other end of the

lengths will permit individuals making the check to sit in

long lead and turn the ignition switch.

seat of truck and observe gauge being checked. To

check, proceed as follows:

(3) If the gauge operates now and

did not operate with the regular wire

Disconnect sender unit being checked

connection, the wiring is at fault.

and hook in tank unit as shown in Figure 44.

Turn on ignition switch and operate float rod

If wiring is satisfactory, then replace

of tank unit by hand.

receiver unit and check again with tank unit.

With float of tank unit at bottom

position, receiver unit should register at

bottom mark on dial.

Move float rod up to top position, then

the needle of the unit being checked should

move to top mark on dial.

NOTE: Allow one minute for receiver

to come to rest.

If the receiver unit operates correctly,

it is then known the sending unit or wiring is

at fault.

NOTE: Do not attempt to repair the

sender unit. When installing a new

engine unit, do not use thread

compound on unit threads, as this

will increase electrical resistance of

unit and cause faulty operation.

Figure 44.

B-87