1. FIGURE 25-1 This cruise control servo unit has an electrical connection with wires that go to the cruise control module or the vehicle computer, depending on the vehicle. The vacuum hoses supply engine manifold vacuum to the rubber diaphragm that moves the throttle linkage to maintain the preset speed.

2. FIGURE 25-2 A cruise control used on a Toyota/Lexus.

3. FIGURE 25-3 Circuit diagram of a typical electronic cruise control system.

4. FIGURE 25-4 A typical electronic throttle with the protective covers removed.

5. FIGURE 25-5 A trailer icon lights on the dash of this Cadillac when the transmission trailer towing mode is selected.

6. FIGURE 25-6 A cruise control symptom-based chart.

7. FIGURE 25-7 A switch and relay control current through the heating grid of a rear-window defogger.

8. FIGURE 25-8 Checking a rear-window defogger grid with a voltmeter
FIGURE 25-8 Checking a rear-window defogger grid with a voltmeter. As the voltmeter positive lead is moved along the grid (on the inside of the vehicle), the voltmeter reading should steadily decrease as the meter approaches the ground side of the grid.

9. FIGURE 25-9 The typical repair material contains conductive silver-filled polymer, which dries in about 10 minutes and is usable in about 30 minutes.

10. FIGURE 25-10 A typical HomeLink garage door opener buttons
FIGURE A typical HomeLink garage door opener buttons. Notice that three different units can be controlled from the vehicle using the HomeLink system.

11. FIGURE 25-11 A typical power window circuit using PM motors
FIGURE A typical power window circuit using PM motors. Control of the direction of window operation is achieved by directing the polarity of the current through the nongrounded motors. The only ground for the entire system is located at the master control (driver’s side) switch assembly.

12. FIGURE 25-12a This independent (driver’s door) power window switch plate looks like a normal simple switch until you turn it over.

13. FIGURE 25-12b Notice that this power window contains a large integrated circuit with a lot of other electronic components to operate the express up and express down.

14. FIGURE An electric motor and a regulator assembly raises and lowers the glass on a power window.

15. FIGURE 25-14 A typical power seat transmission assembly
FIGURE A typical power seat transmission assembly. Even though many of these units can be disassembled, they are designed to be replaced as an assembly if any part inside is defective.

16. FIGURE This power seat motor assembly houses three armatures to provide six way adjustment. Many power seats use one motor and a transmission assembly to operate the various gear nuts needed to move the seat.

17. FIGURE 25-16 Typical power seat circuit diagram
FIGURE Typical power seat circuit diagram. Notice that each motor has a built-in electronic (solid-state) PTC circuit protector. The seat control switch can change the direction in which the motor(s) runs by reversing the direction in which the current flows through the motor.

18. FIGURE The heating wires of a heated seat are a replaceable part, but service requires that the upholstery be removed.

19. FIGURE The heated steering wheel is controlled by a switch on the steering wheel on this vehicle.

20. FIGURE 25-19 A typical electric power door lock circuit diagram
FIGURE A typical electric power door lock circuit diagram. Note that the control circuit is protected by a fuse, whereas the power circuit is protected by a circuit breaker. As with the operation of power windows, power door locks typically use reversible PM nongrounded electric motors. These motors are geared mechanically to the lock-unlock mechanism.

21. FIGURE 25-20 A typical keyless remote fob
FIGURE A typical keyless remote fob. A fob is a term used to describe a key ring.

22. FIGURE A typical vehicle showing the location of the various components of the remote keyless entry system.

23. FIGURE A typical shock sensor used in alarm and antitheft systems. If the vehicle is moved, the magnet will move relative to the coil inducing a small voltage, which will trigger the alarm.

24. FIGURE Door switches, which complete the ground circuit with the door open, are a common source of high resistance.

25. FIGURE A special tool is needed to diagnose a General Motors VATS security system and special keys that contain a resistor pellet.

26. FIGURE The Passlock series of General Motors security systems use a conventional key. The magnet is located in the ignition lock cylinder and triggers the Hall-effect sensors.

27. FIGURE Corrosion or faults at the junction between the wiring and the rear-window electrical grid are the source of many rear-window defogger problems.