i was checked the froum discuss , but i am not found anyone of them,only got a blow motor problem .
now i got 2000 Rx300, and he aways Radiator fan on when i turn key on ( engine not starting)
then i checked the wires , Relays works fine , water switch 1,2 also fine , then i disconnect switch , it it still turn on then i check Cooling Fan System Wiring Diagram . i found a stuff i never see .
put a picture , it on the G103 , and i have no idead for it .. anyone would help ,plz ?

https://docs.google.com/file/d/0BzAR...it?usp=sharing

 

Welcome to Club Lexus.

The red box you drew is the common ground spot for the switch and the motor. This is how ground is connected to the switch and the radiator fan.

As the radiator fan is running, there is no problem in the red box. You need to trace the other end of the fan motor.

When you say the relay is good, what exactly do you mean? The relay has a primary side and the contacts side. If the contacts side is stuck together, then it does not depend upon the primary side and you will get "always on relay".

Try removing the relay and see if the fan motor stops.

Check voltage on the primary side of the relay and if 0v then the problem is the relay.

If the voltage is 12v then trace that as it should be 0v for the radiator fan to not turn.




Salim

 

I'm not sure if the RX is wired this way, but most if not all Toyota's are wired how the fan relay must be energized for the fans to stop. They are wired backwards.

 

thanks for response. i check relays No.1 to no.3 , they are actived when you key on , so i check other way. then i removal water temptuure switch ( 2 pins) plug then both wireds are grounded. i use omnmeter botth ground with engine. i still check diagram. and i relly confused .. BTW i had all relays back up. i already try replace relays for frist step.

 

The diagram is very helpful in tracing the problem, but I was unable to read any text.

Note: Left/right/top/bottom is purely based on where a component is drawn in the diagram. Actual location of the component will be based on where they are located in the RX.

There are 2 motor symbols and my first assumption is that you are having trouble with the motor in the lower section of the drawing.

Step 1:
Remove the fuse on the left (top of the drawing). If the fan stops then the issue is with the the relay on the bottom and associated circuit.

Step 2 (if no change is observed after step 1):
Reinsert fuse on the left and remove fuse on the right.
If the motor stops, then the problem is due to combination of the other two (top and middle).

You can post back or you can then trace the primary sides.

Salim

 

i tried remove fuse then i got 15A one.
if i remove heater (15A ) fuse ,the fan is turn off .
but that water temp switch 1 (2Pin) connect plug both stil get grounded . <-- this is what i confused.
if 2 pins got grounded , how can fan to know when active .

 

 

I still cant read text in the circuit diagram and your note here is does not help as I cant tell which is heater fuse or temp switch pin 1 (2pin) is.

You need to attach a pdf (after making sure the pdf is readable) or refer to objects on the schematic as I did.

Salim

 

how about this ?
https://docs.google.com/file/d/0BzAR...it?usp=sharing

 

To clarify your question is about the water temp switch 2 & Fan 3 relay (terminal 3) going to AC diode.

This produces a logical OR condition ... in words

If the water_temp_switch_2 is on (due to temp) OR Engine Control Module pin E6 is set to ground then complete the Fan relay3 primary side to ground. The diode protects and allows the Control module to go to +12v even when the temp switch makes a connection to ground.

If you remember many cars (not lexus) have a door switch on each door that completes a path to ground for dome light to turn on.

Similarly here we have 2 conditions ... either the temp switch or the Engine control module which can allow the energizing of the relay.

To test which is the reason to turn on your relay -> fan, you need to disconnect the temp switch and the wire from the control module (one at a time).

Since the schematic mentions temp switch 2, that means there is going to temp switch 1 ,,, so make sure you disconnect the right switch.

Salim

 

Any update?

Salim

 

ok i got it now .. frist i check Fan no1 Relay, theni found out there are grounded . then i start check that wire who connected . and i found it under the left lamd , i follow Red/white wire , for it .. then i find high A/c pressure switch for locat it , thanks salimshah for info.
https://docs.google.com/file/d/0BzAR...it?usp=sharing

 

Btw i had recheck the circuit diagram for which one is posive and which one need to been ground also ... then i found it.. but high pressure switch is not sket on circuit diagram

 

and .. i have other problem also . P1030, P1035 .. this car lot of problem..i still testing ..
but i want to know where is second hand front frame assembly to buy ?
https://docs.google.com/file/d/0BzAR...it?usp=sharing

 

The condition does not look good.

Salim