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Pete
Pete, Auto Service Technician
Category: Toyota
Satisfied Customers: 24656
Experience:  Over 17 years diagnosing and repairing automobiles various makes and models with some training and certifications.
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2000 4 RUNNER (3.4)-REAR WINDOW AND REAR KEY SWITCH NOT

Customer Question

2000 4 RUNNER (3.4)-REAR WINDOW AND REAR KEY SWITCH NOT OPERATING FOR LOCKING OR WINDOW OPERATION. rEAR WINDOW DASH SWITCH NOT OPERATING.
PREVIOUS CHECKS:
1) CHILD LOCK ON DRIVERS DOOR NOT ENGAGED
2) REAR WIPER ARM OPERATES AND RETURNS TO STOP POSITION
3) rEMOTE LOCKS AND OPEN REAR TAILGATE - DOES NOT OPEN WINDOW
4) WIRES IN HARNESS FROM BODY TO DOOR GATE NOT DAMAGED
5) TEMPORARY PLUGED IN REPLACEMENT WINDOW MOTOR ASSEMBLE - NO OPERATION
6) CHECKED FUSES mp - GOOD CONDITION
7) REAR DOOR LOCKS WITH REMOTE AND FRONT DOOR SWITCH
8) TAILGATE ECM PLUGGED IN.
WHAT ELSE CAN IT BE. JOHN
Submitted: 1 year ago.
Category: Toyota
Customer: replied 1 year ago.
Additional note- seems strange the rear key switch is not operational. would think the lock would work even is the wiper safety switch was triggered stopping window operation. rear window wiper fully operational
Expert:  Pete replied 1 year ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

Your model uses what is called a Back Door ECU.If this ECU has failed electronically this will cause this fault here needing replaced.I have seen this module fail before causing issues like this here.This will have to be tested further electronically as well as having the fault codes read out to be sure this is the cause here.

Thanks Pete

Customer: replied 1 year ago.
Pete, what test can i perform on the rear ECU to find out if it is faulty? do you have a part number? is the window wiper and defroster run from the ECU (they are operational). i found it strange that the rear key switch does not operate to lock and open the door. i believe the remote locking and the cabin lock are a separate circuit and it works from both. let me know. i do not have access to the car until tonight to do any checks. i disconnected the battery to reset the system but it did not do anything. thanks john
Expert:  Pete replied 1 year ago.

The rear wiper runs off of the Back door ecu itself as well.Part of this ecu can be faulty internally causing the issues here and part of it may be working allowing wiper operation.

You should have a red wire to the rear window motor and a green wire.These feed power and ground to the rear window motor.These signals come from the back door ecu.If you have no power or ground from these wires when operating the rear window this will indicate the rear door ecu is faulty.I believe your rear door ecu does have its correct powers and grounds as it is allowing the wiper operation so this in turn leads to a faulty ecu in most cases.

Unfortunately my info isn't showing me the part number for this ECU.You should be able to get the part number from a local dealers parts department at no charge then find out the cost of the module as well.

Thanks Pete

Customer: replied 1 year ago.
pete, thanks for your help so far . i will double check the power to the motor again but i did plug in a new motor and it did not work so i would think no power. how do i rule out that another switch is not the problem. IE. The window wiper position switch that tells the window that it can open because the wiper is in the dock position? Is the rear key switch lock operated thru the ECU? john I do not want to just start buying expensive parts to find out it was not the problem.
Expert:  Pete replied 1 year ago.

If you have no power or ground signals to the motor when trying to operate it this can indicate the ECU for the rear door is faulty.I may be able to locate some wiring diagram issue on this here if you like and offer the diagram service for you if you know how to read the diagrams but my info isn't showing any testing steps for this issue here.Let me know if this is something you would want and I can check and see if I can locate it and offer the service to you.

Thanks Pete

Customer: replied 1 year ago.
pete , being straight forward, as Toyota mechanic not having the part number for the ecu or wire diagram to reference concerns m me . you want additional pay to reference this info? based on the original information and diagnostic tests I performed I expected a more systematic approach to find the fault like you would perform on the Toyota cars you service. I am not satisfied with the service you provided. please explain. john
Expert:  Pete replied 1 year ago.

I apologize my info hasn't helped here and some of my info is some what limited.I will have to open this question up for others here to see if they can assist further on this as someone else here may have more info on what to check or do with this issue.I hope you can get this resolved with ease.No need to reply to my last post here unless it is a last resort as it will keep your question locked to me and others will not be able to view it.

Thanks Pete

Customer: replied 1 year ago.
Pete, did not hear from anybody in the last 3 days.

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