AUT 242-Chapter 7

4. When testing a relay using an ohmmeter, which two terminals should be touched to measure the coil resistance?

86 and 85

2. List and identify the terminals of a typical ISO type relay.

86-Power side of the coil 85-Ground side of the coil 30-Switch power for the relay 87-Normally open output (N.O) 87a-Normally closed output (N.C)

6. Which relay terminal is the normally closed (N.C.) terminal?

87a

4. How can a tone generator be used to locate a short circuit?

A tone will be generated as long as there is a continuous electrical path along the circuit. The signal will stop if there is a short-to-ground or an open in the circuit

7. Technician A says that there is often more than one circuit being protected by each fuse. Technician B says that more one circuit often shares a single ground connector. Which technician is correct?

Both A nor B

5. Technician A says that a good relay should measure between 60 and 100 ohms across the coil terminals. Technician B says that OL should be displayed on an ohmmeter when touching terminals 30 and 87. Which technician is correct?

Both Technicians

1. List the numbers used on schematics to indicate grounds, splices, and connectors and where they are used in the vehicle.

Grounds, splices and connectors numbers listed on a schematic are 305 for ground located in the passenger compartment, 102 for connectors located under the hood 202 located under the dash

Single-pole, double-throw (SPST)-

a switch that has three terminals, one wire in and two wires out

8. Two technicians are discussing finding a short-to-ground using a test light. Technician A says that test light connected in place of the fuse, will light when the circuit that has the short is disconnected. Technician B says that the test light should be connected to the positive (+) and negative (-) terminals of the battery during this test. Which technician is correct?

Neither Technician

10. For an electrical device to operate, it must have .

Power and a ground

3. All switches illustrated in schematics are

Shown in their normal position

3. List three methods that can be used to help locate a short circuit.

Test Light Method, Ohmmeter Method and Gauss Gauge Method

9. A short circuit can be located using a .

Test light, Gauss gauge and Tone generator

2. Where is connector C250?

Under the dash

1. On a wiring diagram, S110 with a ".8 BRN/BLK" means

a Splice of a brown with black stripe, wire size being 0.8mm2 (18 gauge AWG)

Double-pole, single-throw (DPST)-

a switch has two positions (off and on) an can control two separate circuits

Single-pole, single-throw (SPDT)-

a switch that has only two positions, on or off

Double-pole, double-throw (DPDT)-

a switch that has six-terminals-three for each pole

Tone generator tester-

generates a tone that can be heard through a receiver (probe) to locate a short-to-ground or an open circuit

Coil-

is a device that provides the magnetic pull to a movable armature (arm)

Gauss gauge-

is a handheld meter that responds to weak magnetic fields. It is used to observe pulsing magnetic fields, which is indicated on the gauge as needle movement

Momentary switch-

is a switch primarily used to send a voltage signal to a module or controller to request that a device be turned on or off

Short circuit-

is an electrical connection to another wire or to ground before the current flows through some or all of the resistance in the circuit

Relay-

is an electromagnetic switch that uses a movable arm

Throws-

refer to the number of output circuits

Poles-

refers to the number of circuits completed by the switch

Wiring schematic-

sometimes called a diagram shows electrical components and wiring using symbols and lines to represent components and wires

Terminal-

the metal part attached at the end of a wire

Normally closed (N.O.)-

this type of switch is electrically connected to its internal contacts and current will flow through the switch

Normally open (N.C.)-

this type of switch is not connected to its internal contacts and no current will flow