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Installing cruise control in base model. Wrong brake switch?

Discussion in 'Gen 2 Prius Accessories & Modifications' started by Frayadjacent, Aug 2, 2009.

  1. Frayadjacent

    Frayadjacent Resident Conservative

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    Well, I finally got around to ordering the parts for the cruise control in my 09 Base.

    I ordered the original parts from a list I'd found here from Toyotapartszone.com. They replied and said that a couple of the part numbers had been superseded, and were a little more expensive.

    One part was the brake light switch. Part number 84340-20060 was replaced with 84340-04030.

    I neglected to look up and order the screws to mount the switch, so I did that and put the install on hold. Well, I figured I'd install the brake switch so that it will be ready.

    PROBLEM - the switch has a different connector than the harness that connects to it. The cable DOES have four wires, but will not connect to the switch I was sent.

    SO, I'm thinking the vendor I ordered from didn't have stock of the correct switch, but had a similar part (for 2x the price, I might add) and sold me that one.


    Can anyone verify that the original four pin brake switch is a DIRECT replacement for the base model brake light switch? That it will connect right up? If so, I'm going to have to find somewhere that has or can get the original part number. If not, well, then my CC just won't cancel when I hit the brakes. :(


    Added: Here's the switch I received. This is the INCORRECT switch:

    [​IMG]
     
  2. Frayadjacent

    Frayadjacent Resident Conservative

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    Found another post that lists the brake switch as p/n 84340-47020, and checked, it has not been superseded by any other part number. Perhaps this is the correct switch?
     
  3. Frayadjacent

    Frayadjacent Resident Conservative

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    Well, today I received the screws to mount the switch in the steering wheel, so I did so. Disconnected the 12v battery and opened up the hub. Installation was STUPID EASY. Disconnecting the airbag is NOT necessary. Heck, if you're careful, you could probably do the whole thing with the battery connected, though I wouldn't recommend it.

    I don't have the correct brake switch installed, and figured the cruise would work without it, just that it wouldn't cancel if the brake pedal was depressed.

    I found out that this is incorrect. With the pedal depressed when starting the car, hitting the on/off button on the CC stalk did turn on the CRUISE indicator in the dash. While moving without the brake pedal depressed, hitting the on/off switch causes the CRUISE indicator to flicker. It's apparently confused since it's not getting a signal that it thinks it should.

    This makes me think that the cruise control system monitors BOTH sides of the DPDT brake switch.
     
  4. RobH

    RobH Senior Member

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    There are actually two switches inside the brake switch module. One normally open, and the other normally closed. The normally open one obviously controls things that happen when the brake is depressed (brake lights, gear selection, Power button). I guess the normally closed one is part of the cruse control circuit. It allows cruse control to operate, unless the brake is depressed. Now why they didn't just use a relay to invert the normally open signal is another question...
     
  5. Frayadjacent

    Frayadjacent Resident Conservative

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    AAAAARRRRRRRRRGGHHHHHHH!!!!!!!

    Got the second part... part number 84340-47020... and it's the SAME as the one in the picture above. Well, except that the pushbutton end is orange and not white. The connector is the SAME.


    WTH Toyota? What freaking part will work in my car!?!?!?
     
  6. Frayadjacent

    Frayadjacent Resident Conservative

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    It's actually the other way around. The normally closed side is for the brakes. The switch is actually pressed when the pedal is at rest, since that is the only absolute position of the pedal. When the pedal is depressed, the button is released, and the normally closed side closes, activating the brake lights.

    I'm wondering if I can just short the other two wires in the harness. Trick the system into thinking the brake is not depressed.

    But then, I don't know what will happen when the brakes are pressed... aside from not canceling the CC setting...
     
  7. Frayadjacent

    Frayadjacent Resident Conservative

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    Ok, I said to myself, fuggedaboudit... and called the dealer. Another member here had emailed me a kit part number that he was able to obtain from his dealer to enable CC in his 08 base model.

    My dealer's parts department doesn't recognize the part number... so I gave the guy the two part numbers of the incorrect switches and asked him to check to see if he could find something different. He found a part and is ordering it. They should have it tomorrow, so I can go up there and inspect it before I plop down the cash.
     
  8. Frayadjacent

    Frayadjacent Resident Conservative

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    Looks like I have the right part now! My local dealer found part number 84340-30110, and it appears correct. I'm about to install.
     
  9. Frayadjacent

    Frayadjacent Resident Conservative

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    The part works! I now have Cruise Control!

    Wow... this means the first two parts I ordered, part numbers I found here on PC are wrong. I hope that this thread will help any other 08 and 09 BASE owners who want to install cruise control!

    So to conclude, the CORRECT part number for the brake light switch is:

    84340-30110