Fan thermostat switch not working properly

Tiny
HENRY. N
  • MEMBER
  • 2000 LEXUS RX 300
  • 6 CYL
  • 4WD
  • 90,009 MILES
The fan refuse to start automatically.
Monday, November 25th, 2019 AT 11:01 PM

1 Reply

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

Have you checked the fan relays? Here are the directions for testing them. Also, the attached pictures correlate with the directions.

____________________________________

2000 Lexus Truck RX 300 AWD V6-3.0L (1MZ-FE)
Cooling Fan Relay(s)
Vehicle Engine, Cooling and Exhaust Cooling System Radiator Cooling Fan Radiator Cooling Fan Motor Relay Testing and Inspection Component Tests and General Diagnostics Cooling Fan Relay(s)
COOLING FAN RELAY(S)
INSPECTION
1. INSPECT NO.1 COOLING FAN RELAY

pic 1

a. Remove the No.1 cooling fan relay. (Marking: FAN NO.1)

pic 2

b. Inspect the No. 1 cooling fan relay continuity.
1. Using an ohmmeter, check that there is continuity between terminals 3 and 5.
If there is no continuity, replace the relay.
2. Check that there is no continuity between terminals 1 and 2.
If there is continuity, replace the relay.

Pic 3

c. Inspect the No.1 cooling fan relay operation.
1. Apply battery voltage across terminals 3 and 5.
2. Using an ohmmeter, check that there is continuity between terminals 1 and 2.
If there is no continuity, replace the relay.
D. Install the No.1 cooling fan relay.
2. INSPECT NO.2 COOLING FAN RELAY

pic 4

a. Remove the No.2 cooling fan relay. (Marking: FAN NO.2)

pic 5

b. Inspect the No.2 cooling fan relay continuity.
1. Using an ohmmeter, check that there is continuity between terminals 3 and 5.
If there is no continuity, replace the relay.
2. Check that there is continuity between terminals 2 and 4.
If there is no continuity, replace the relay.
3. Check that there is no continuity between terminals 1 and 2.
If there is continuity, replace the relay.

Pic 6

c. Inspect the No.2 cooling fan relay operation.
1. Apply battery voltage across terminals 3 and 5.
2. Using an ohmmeter, check that there is no continuity between terminals 2 and 4.
If there is continuity, replace the relay.
3. Check that there is continuity between terminals 1 and 2.
If there is no continuity, replace the relay.
D. Install the No.2 cooling fan relay.
3. INSPECT NO.3 COOLING FAN RELAY

pic 7

a. Remove the No.3 cooling fan relay. (Marking: FAN NO.3)

pic 8

b. Inspect the No.3 cooling fan relay continuity.
1. Using an ohmmeter, check that there is continuity between terminals 3 and 5.
If there is no continuity, replace the relay.
2. Check that there is no continuity between terminals 1 and 2.
If there is continuity, replace the relay.

Pic 9

c. Inspect the No.3 cooling fan relay operation.
1. Apply battery voltage across terminals 3 and 5.
2. Using an ohmmeter, check that there is continuity between terminals 1 and 2.
If there is no continuity, replace the relay.
D. Install the No.3 cooling fan relay.

______________________________________

Let me know.

Joe
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Tuesday, November 26th, 2019 AT 7:13 PM

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