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Pete, Auto Service Technician
Category: Toyota
Satisfied Customers: 29068
Experience:  Over 17 years diagnosing and repairing automobiles various makes and models with some training and certifications.
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I have a 2006 Toyota Highlander Hybrid, over the last 2 Days

Customer Question

I have a 2006 Toyota Highlander Hybrid
JA: Are you fixing your Highlander Hybrid yourself? What have you tried so far?
Customer: over the last 2 Days we have had a dead battery 3 times, it seems that the (head and tail) lights cannot be turned off
JA: Did you test the battery with a voltmeter? And have you ever changed one before?
Customer: The batter was checked twice by AAA and found to be in perfect working condition, Even when the lights switch is completely turned of, the key removed and the car locked; the lights(head and tail) remain on and the warning chimes continue until the battery is dead. The car will start with a boost and run perfectly, but the lights will simply not turn off.
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 2 months ago.
Category: Toyota
Expert:  Pete replied 2 months ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

What is causing this issue here is a fault with a shorted component keeping these lights on.This will drain the battery fairly quick.

Since this is both head lights and tail lights are on and these are all controlled by the Body ECU control unit on separate wiring circuits with separate relays it is very rare to have several relays fail at the same time or several shorts in wiring to all of these lights so this leaves the Body ECU at fault internally.When the Body ECU fails internally it can short out and keeps the lights on like this here then draining the battery.The body ecu sounds like it needs replaced to resolve this fault.

The fault codes need read out/checked with a compatible scan tool plugged into your vehicle to see what codes are set in the body ecu as this will help to pinpoint it as the fault here.This is a $800 ecu unfortunately.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated ( should be a link to click on here or above).You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 2 months ago.
I will read the Fault Codes and send them to you, this will take a little time, and I would like to keep this conversation open.
Expert:  Pete replied 2 months ago.

No problem.Keep in mind for future reference or any time that if a rating is left the question will still remain open.You can rate at any time and we can also continue on the same page at any time.

Let me know if you need anything else and feel free to rate my help here or above ( should be a link to click on ) as this is how I receive credit for my time.Your 5 star rating is appreciated

Thanks Pete