Lexus ES300 (1997 year). Manual — part 606

7

B

Q : Explains the system outline.

R : Indicates values or explain the function for reference during troubleshooting.

S : Indicates the reference page showing the position on the vehicle of the parts in the system circuit.

Example: Part “P 4” (Power Window Master SW) is on page 21 of the manual.

* The letter in the code is from the first letter of the part, and the number indicates its order in

parts starting with the letter.
Example: P 4

HINTS:

Part is 4th in order
Power Window Master SW

Junction connector (code: J1 to J19) in this manual
include a short terminal which is connected to a
number of wire harnesses. Always perform inspec-
tion with the short terminal installed. (When instal-
ling the wire harnesses, the harnesses can be con-
nected to any position within the short terminal
grouping. Accordingly, in other vehicles, the same
position in the short terminal may be connected to
a wire harness from a different part.)
Wire harness sharing the same short terminal
grouping have the same color.

T : Indicates the reference page showing the position on the vehicle of Relay Block Connectors in the system

circuit.

Example: Connector “1” is described on page 16 on this manual and is installed on the left side of the

instrument panel.

U : Indicates the reference page showing the position on the vehicle of J/B and Wire Harness in the system

circuit.

Example: Connector “3B”connects the Cowl Wire and J/B No. 3. It is described on page 14 of this manual,

and is installed on the instrument panel left side.

V : Indicates the reference page describing the wiring harness and wiring harness connector (the female wiring

harness is shown first, followed by the male wiring harness).

Example: Connector “ID1”connects the front door RH wire (female) and cowl wire (male). It is described

on page 26 of this manual, and is installed on the right side kick panel.

W : Indicates the reference page showing the position of the ground points on the vehicle.

Example: Ground point “IC” is described on page 24 of this manual and is installed on the cowl left side.

X : Indicates the reference page showing the position of the splice points on the vehicle.

Example: Splice point “I 5” is on the Cowl Wire Harness and is described on page 24 of this manual.

8

B HOW TO USE THIS MANUAL

The “Current Flow Chart” section, describes which parts each power source (fuses, fusible links, and circuit
breakers) transmits current to. In the Power Source circuit diagram, the conditions when battery power is
supplied to each system are explained. Since all System Circuit diagrams start from the power source, the power
source system must be fully understood.

* The system shown here is an EXAMPLE ONLY. It is different to the actual circuit shown in the SYSTEM CIRCUITS SECTION.

H POWER SOURCE (CURRENT FLOW CHART)

The chart below shows the route by which current flows from the battery to each electrical source (Fusible Link, Circuit Breaker, Fuse,

etc.) and other parts.

The next page and following pages shown the parts to which each electrical source outputs current.

POWER SOURCE

9

B

The ground points circuit diagram shows the connections from all major parts to the respective ground points.
When troubleshooting a faulty ground point, checking the system circuits which use a common ground may
help you identify the problem ground quickly. The relationship between ground points ( , and
shown below) can also be checked this way.

EA

IB

IC

* The system shown here is an EXAMPLE ONLY. It is different to the actual circuit shown in the SYSTEM CIRCUITS SECTION.

J GROUND POINT

10

C TROUBLESHOOTING

(a)

Disconnect the battery terminal or wire so there is no
voltage between the check points.

(b)

Contact the two leads of an ohmmeter to each of the
check point.

If the circuit has diodes, reverse the two leads and check
again.
When contacting the negative lead to the diode positive side
and the positive lead to the negative side, there should be
continuity.
When contacting the two leads in reverse, there should be
no continuity.

(c)

Use the volt/ohmmeter with high impedance (10k

Ω

/V

minimum) for troubleshooting of the electrical circuit.

CONTINUITY AND RESISTANCE CHECK

VOLTAGE CHECK

(a)

Establish conditions in which voltage is
check point.

Example:

A – Ignition SW on
B – Ignition SW and SW 1 on
C – Ignition SW, SW 1 and Relay on (SW2 off)

(b)

Using a voltmeter, connect the negative lead to a
ground point or negative battery terminal, and a
positive lead to the connector or component terminal.
This check can be done with a test light instead of a
voltmeter.