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Avalon Fanatic
2002 Avalon XLS
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Discussion Starter · #1 · (Edited)
Recently i have been doing electrical work on my 2000 Avalon XLS. At the moment the passenger door ECU (passenger do power window and lock switch) is not in the car due to a malfunction. I have a replacement on order and the car currently works absolutely perfectly other than the passenger window not rolling down (because of this missing ECU). My concern is Every time I go to unlock the car with my key fob the horn sounds for a brief second. Which it has never done before. The other thing is the doors don't unlock. I then have to then press the button a second time and it unlocks and I go on my marry way. So the question I have is this horn sounding a bad thing? Or is it just the car being confused due to the lack of passenger door control switches? I will know for sure when I get the new ECU this week and put it in however I just want to be sure the system is fine, while Jap electronics are great they cost $$$$ to replace.
 

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Recently i have been doing electrical work on my 2000 Avalon XLS. At the moment the passenger door ECU (passenger do power window and lock switch) is not in the car due to a malfunction. I have a replacement on order and the car currently works absolutely perfectly other than the passenger window not rolling down (because of this missing ECU). My concern is Every time I go to unlock the car with my key fob the horn sounds for a brief second. Which it has never done before. The other thing is the doors don't unlock. I then have to then press the button a second time and it unlocks and I go on my marry way. So the question I have is this horn sounding a bad thing? Or is it just the car being confused due to the lack of passenger door control switches? I will know for sure when I get the new ECU this week and put it in however I just want to be sure the system is fine, while Jap electronics are great they cost $$$$ to replace.
The ECU is the engine control unit... So not sure what that's doing with the window....

The locks on mine are one click drivers door opens, second click the rest open, maybe check with the dealer?
 

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Avalon Fanatic
2002 Avalon XLS
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46 Posts
Discussion Starter · #3 ·
The ECU is the engine control unit... So not sure what that's doing with the window....

The locks on mine are one click drivers door opens, second click the rest open, maybe check with the dealer?
I checked the schematic workbooks, yes the ECU is referred to as the main body ECU but this window switch was labelled as the passenger door ECU. I'm just wondering if there could possibly be something else involved down the line that could be damaged and I am hoping to avoid the dealer. This is a total shot in the dark with this problem I was just wondering if anyone else had the same or similar problem.

What happened is there was an electrical short in the wiring of the interior lamps, these lamps are wired to to the switch that controls the windows and power locks. The short caused the burnout of a MOSFET in the green circuit board. From what I can tell this is the only part that was damaged, so I replaced it with an entirely new switch. In the end I just want to make sure I don't plug up the new switch and it fries again. I eliminated the short and resolved that problem and everything else is functioning normally.
 

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I checked the schematic workbooks, yes the ECU is referred to as the main body ECU but this window switch was labelled as the passenger door ECU. I'm just wondering if there could possibly be something else involved down the line that could be damaged and I am hoping to avoid the dealer. This is a total shot in the dark with this problem I was just wondering if anyone else had the same or similar problem.

What happened is there was an electrical short in the wiring of the interior lamps, these lamps are wired to to the switch that controls the windows and power locks. The short caused the burnout of a MOSFET in the green circuit board. From what I can tell this is the only part that was damaged, so I replaced it with an entirely new switch. In the end I just want to make sure I don't plug up the new switch and it fries again. I eliminated the short and resolved that problem and everything else is functioning normally.
Have you checked the fuses and the door switch as well?
 

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Avalon Fanatic
2002 Avalon XLS
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46 Posts
Discussion Starter · #5 ·
Have you checked the fuses and the door switch as well?
Fuses, no. What would I be looking for along the lines of such?

The door switch with the power window and locks is what is being replaced on the passenger side. Everything functions normally other than the horn sounding on unlock and the passenger side window, due to missing switch. Power locks and windows all around work fine, as well as the key fob functions.

From what I can tell it is simple the ECU determining something is missing or there is a code that needs to be reset. I am not getting any warning lights, however I haven't had it scanned to see if any codes are popping up.
 

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Avalon Fanatic
2002 Avalon XLS
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46 Posts
Discussion Starter · #7 ·
You would look for a blown fuse? If there was a short the fuse should have tripped. All of the interior fuses should be looked at for scorch marks.
My bad, I misunderstood. I checked fuses first thing I figured you meant something wrong with the fuse relay and such.

Thanks for your help, but I seem to have discovered the reason, the horn sounding is the systems way of telling me the the switches on the passenger door are missing and thus forth the window and such do not function on that side. There was a short in the interior lighting system causing the switch to fry, I am replacing te switch this weekend and hopefully this wil resolve everything.
 

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My bad, I misunderstood. I checked fuses first thing I figured you meant something wrong with the fuse relay and such.

Thanks for your help, but I seem to have discovered the reason, the horn sounding is the systems way of telling me the the switches on the passenger door are missing and thus forth the window and such do not function on that side. There was a short in the interior lighting system causing the switch to fry, I am replacing te switch this weekend and hopefully this wil resolve everything.
I Was thinking about this, the ES350 and Jeep bouth would horn on unlock, Jeep had an option to turn it on /off and ES needed the dealer to disable it, (neither had switch issues) maybe your dealer could disable it.
 

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Avalon Fanatic
2002 Avalon XLS
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46 Posts
Discussion Starter · #10 ·
I just realized my 02 XL beeps on unlock, thats not what you mean by the horn is it?
No sir, this is a full fledged beep of the horn. Real short beep. From my deduction it is simply the system telling me that the switch on the passenger side is missing. Will know for sure tomorrow night when I put the new switch in.
 

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Avalon Fanatic
2002 Avalon XLS
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46 Posts
Discussion Starter · #11 ·
I put the new passenger door switch in last night and the window, and power lock buttons are functioning perfectly.

However I got a switch from a XL model and I have an XLS, therefore my right power window doesn't work. Slight problem, But I'll live with it to have my window and unlock button back.

(Just in case anyone else runs across a similar problem this is how I solved it)
 

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Avalon Fanatic
2002 Avalon XLS
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46 Posts
Discussion Starter · #13 ·
Are they the same part number? If so it should work.
The switch itself (mechanically) is the same part number on the XL model as it is on the XLS model. The circuit board inside of the switch however is different. The board from my XLS has several relays that I presume are for the power window up, down, and memory. The XL board doesn't have these relays thus rendering the mirror inoperable. I am replacing the fault with my original board to fix this.

Essentially for anyone looking for a replacement switch many people may sell a switch that has the same exterior part number but ensure the circuit boards within are the same.
 
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