GMC 1986 P-Truck Service Manual page 248

DIAGNOSIS OF THE STEERING COLUMN (CONT.)
PROBLEM
Tone Alarm Does 13. If the tone alarm fault has not yet been
Not Sound With Key
Fully Inserted In
Lock Cylinder With
D river's Door Open
(Cont.)
14. If the fault has not yet been isolated
Tone Alarm 1. Door jamb switch on driver's side mal­
Continues To
Operate With Key In 2. Wire from signal switch to door jamb
The Lock Cylinder
W ith The D river's
Door Either Opened
Or Closed And
Ceases When Key Is
Removed
Tone Alarm
1. Lock cylinder binding (turn lock toward
Continues To
Operate With Key
Out, But Stops When
D river's Door Is
Closed 2. Chips, foreign material in lock cylinder
3. Sticky lock cylinder actuator tip.
4. Damaged or broken tone alarm switch.
5. Tone alarm switch contact gap is too
POSSIBLE CAUSE
detected, connect a continuity meter
(or light) to the male E and F connector
contacts. Insert the key the full depth
into the lock cylinder. If contact is
made with the key in, and is not made
with it out, the function is normal. Re­
trace the initial diagnostic steps. If con­
tact is not established, the fault is in
the column.
and repaired, connect ohmmeter to the
tone alarm switch probes. Fully insert
and remove the key from the lock cylin­
der. If contact is made with the key in,
and is broken with it out, the function is
normal. Retrace the diagnostic steps.
If contact is not made, the fault is in
the lock cylinder or tone alarm switch.
adjusted or inoperative.
switch shorted.
start position. If tone alarm stops in the
run position or when turned past run
run towards the start, the problem is a
sticky lock cylinder actuator).
bore.
close.
STEERING COLUMN 3B4-9
CORRECTION
13. With the fault isolated in the column,
disassemble the upper end of the col­
umn until the signal switch mounting
screws have been removed. Lift the
switch and check the probes of the
tone alarm switch to ensure good
contact with the pads in the signal
switch. Bend the probes, if required,
then reseat the signal switch and in­
stall the three screws. Check the
function.
14. Setting the contact gap. Press a
0.75 mm (0.030 inch) wire type spark
plug gap wire with flat piece of stock
on the actuator pad. If contact is not
made, adjust switch until positive
contact is made (use ohmmeter).
With positive contact at 0.75 mm
(0.030 inch) use a 0.65 mm (0.025
inch) plug gap wire beneath the flat
stock. No contact should occur. Ad­
just. When the switch will make con­
tact with the 0.75 mm (0.030 inch)
wire and not with the 0.65 mm (0.025
inch) wire, the tone alarm switch is
set at the low limit.
1. Adjust or replace as required.
2. If on signal switch side, replace sig­
nal switch. If on chassis side, find
and repair.
This condition indicates the lock
cylinder or tone alarm switch is at
fault. To verify, check for continuity at
the E and F male connector contacts
with the key removed from the cylin­
der. If continuity exists, the fault is in
the column.
1. Replace the lock cylinder.
2. Remove, assem ble and recheck
function.
3. Replace the lock cylinder.
4. Replace the tone alarm switch.
5. Adjust as specified.