Aerostar 2WD V6-245 4.0L (1990)
Cruise Control Switch: Testing and Inspection
1.
Apply brake pedal and ensure brake lights operate. If found satisfactory, proceed to step 2. If found unsatisfactory, check stop lamps circuit.
2.
Press horn pad to sound horn. If found satisfactory, proceed to step 3. If found unsatisfactory, check horn circuit.
3.
Locate 6-pin connector at speed control amplifier.
4.
With ignition Off and 6-pin connector still connected to amplifier, connect an ohmmeter between black wire and ground on Ranger, Bronco II,
Explorer and Aerostar with mechanical cluster or black-white wire on Aerostar with electronic cluster.
5.
Check resistance to ground to ensure amplifier is grounded. If amplifier is not grounded, repair and retest. If amplifier is properly grounded, turn
ignition to On position while making the following voltage checks:
a.
Check circuit 296 (white/purple wire) on Aerostar models or circuit 302 (dark blue wire) on Bronco II, Explorer and Ranger models. If 12
volts are present, proceed to step b. If not present, check speed control fuse and 296 circuit wire continuity.
b.
Apply brake pedal and check circuit 511 (light green wire) for 12 volts on Ranger, Bronco II and Explorer or circuit 810 (red/light green
wire) on Aerostar. If 12 volts is not present, check continuity between stop lamp switch and amplifier and repair as necessary. If there is
continuity, replace amplifier.
c.
Check circuit 151 (light blue/black wire) for approximately 7.8 volts. If 7.8 volts is not present with amplifier properly grounded and 12 volts
at circuit 296 white/purple wire on Aerostar models or 302 dark blue wire on Bronco II, Explorer and Ranger models, verified, check for On
button sticking. If 12 volts is present or a short circuit to ground on circuit 151 (light blue/black wire) between amplifier and steering column
brush assembly. If zero volts is present and both the On button and 151 wire are functioning properly, replace amplifier and repeat test. If 7.8
volts is present, proceed to step 6.
6.
Check following voltages between circuit 151 (light blue/black wire) and amplifier ground while rotating the steering wheel with horn pad switch
depressed making the following checks:
a.
No button pressed, 7.8 volts.
b.
On, 12.0 volts.
c.
Off, 0.0 volts.
d.
Resume, 6.5 volts.
e.
Accel, 4.5 volts.
f.
Coast, 1.5 volts.
7.
If values are incorrect or fluctuate, proceed to Step 8. If values are correct, horn pad switches are operating properly. Proceed to step 17.
8.
With ignition Off, disconnect the 6-pin connector from amplifier, then check following resistances between circuit 151 (light blue/black wire) and
amplifier ground with horn pad switch depressed while rotating steering wheel. Ohmmeter readings should as follows with switch positions as
indicated:
a.
Off, 0--1 ohm.
b.
Accel, 646-714 ohms,
c.
Coast, 114-126 ohms.
d.
Resume, 2090-2310 ohms.
9.
If values are incorrect or fluctuate, proceed to step 10. If values are correct, replace amplifier and repeat step 4.
10.
On models except 1992 Aerostar, remove steering wheel horn pad attaching screws in back cover, then disconnect electrical connectors from
wheel.
11.
On 1992 Aerostar, disable airbag system as outlined in MAINTENANCE PROCEDURES Remove airbag module, then disconnect clock
spring contact electrical connector at upper center area of steering wheel.
12.
On all models, connect suitable ohmmeter between circuit 151 (yellow/light blue wire) and circuit 6 (dark/blue wire) on horn pad on all models,
except 1992 Aerostar or black wire connector on 1992 Aerostar models. Depress On switch and check for a reading of 0-1 ohms.
12.
If reading is not correct, replace switch assembly.
13.
Pull steering wheel, then check for continuity of circuit 151 (light blue/black wire) and circuit 57 (black wire) between amplifier 6-pin connector
and brush assembly on models except 1992 Aerostar or clockspring on 1992 Aerostar models.
14.
If there is no continuity, check for continuity between 3-pin brush assembly wiring connector and brushes or clockspring at steering wheel, then
between mating 3-pin connector and amplifier 6-pin connector. Repair or replace brush or clockspring assembly as necessary.
15.
If there is continuity for both circuits, clean brush assembly and slip rings in a suitable solvent and lubricate with suitable lubricant.
16.
Install wheel and horn pad and repeat step 4.
17.
Connect a suitable ohmmeter between circuit 150 (green/white wire) and speed sensor ground circuit 563 (orange/yellow wire) on Ranger, Bronco
II and Explorer or 397 (black/white wire) on Aerostar.
18.
If resistance is not between 180-250 ohms, check continuity between 6-pin connector at amplifier and 2-pin speed sensor connector at transmission
and repair as necessary.
19.
If resistance is correct, the speed sensor wiring is functioning properly. Not all speed sensor problems can be identified by a resistance check.
Replacement with a known good sensor may be required.
