START - FIRST CHART FOR DIAGNOSIS OF DDEC III/IV USING DDR (Cont'd) -726280615

TM 9-2320-364-20-1

Section IV. TROUBLESHOOTING CHARTS (Cont.)

C. START - FIRST CHART FOR DIAGNOSIS OF DDEC III/IV USING DDR (Cont'd)

STEP/SEQUENCE

RESULT

WHAT TO DO NEXT

START-8

Check for Short

Plug DDR into Connector.

Select SWITCH/LIGHT STATS

on DDR.

Read Diagnostic Request SW.

ON.

Ckt #528 is shorted

status.

to ground. Repair short,

then go to START-30.

OFF.

Go to Chart 9, page 2-605.

START-9

Check for +12

Volts at DDR

Connector

Turn ignition on.

Greater than

There is a problem with either

Read voltage at the DDR

or equal to 10.0 volts.

the DDR or the data link lines.

connector, from pin "H" (red lead)

Go to C 7-4, page 2-595. (For

to pin "A" (black lead).

diagnosis of DDEC III/IV without a

DDR, go to CEL-1 on page

Less than

Either the switched +12 volt line

10.0 volts.

or the ground line is open to the

DDR connector. Repair open.

Then go to START-30.

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