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Door Open (Ajar) Warning Light Staying On: REPAIRED

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by FlyboyTR, Jun 23, 2011.

  1. FlyboyTR

    FlyboyTR Member

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    My 08 Prius developed a hiccup yesterday. While driving down the interstate there was an occasional red flash from the dash. It would come and go so fast that by the time I could actually process it and focus…it was gone. I had to stop by the dentist office…as I was ready to walk out the door I heard a car in the parking lot with the horn/alarm sounding. I mentioned to the folks in the waiting room that someone’s alarm was going off. A lady replied…â€It’s that green Prius with the bike rack!â€

    Sure enough…it was mine! I was unable to find any causal factor. I left there and at my next stop…the horn/alarm started sounding just as I walked through the entrance door to Home Depot…back to the parking lot.

    This time the Door Ajar/Open light on the dash was lit. I opened and closed all the doors and hatch. The Door Ajar light was still on… I then manually manipulated all the door switches and opened/closed/slammed the hatch several times. No Joy… I drove home.

    After getting home I searched this Forum for help. About the only thing I was able to find was that…it was probably the hatch, the switch is sealed within the locking/latch mechanism and that I could simply just unplug it. So I began troubleshooting.

    After removing the rear hatch/floor, plastic bin, etc. I removed the plastic cover from around the latch (above the bumper…not on the hatch lid), then removed the longer plastic cover that runs along the same area and provides the cover for the area between the rubber gasket and the inside of the hatch/floor area. Now I was able to see the latch mechanism and associated wiring (looking down toward the spare tire well). I also had the hatch light turned on (left side) which was easier to see than the Door/Ajar light on the dash.
    [​IMG]

    I manually tripped the latch and the light flickered. I pressed down on the latch (hoping to put more pressure on the internal switch)…the light continued to flicker. Using a 10mm socket, I removed the latch, wiring retainers and disconnected the plug. The electrical plug, located about 8†to the left of the latch has 4 wires. The two on the bottom power the electrically operated latch and the two on top go to the Door Ajar switch (the one that is inside the latch assembly).

    I noticed a little bit of corrosion and discoloration on one of the male pins (the plug that is connected to the latch end of the wiring). The female plug (connected to the car end of the wiring) also had some discoloration.
    [​IMG]
    I plugged them back together and found that as I moved the wires/plug the light would flicker and change…sometimes turning off. I unplugged it and connected my ohm meter (using small jumper wires with clips) to the two top (male) pins on the switch end of the plug. The switch tested fine. I even tested it with my homemade battery powered continuity light (wanting to test the switch under a load). I also wiggled the wires going into the plug itself…Perfect…no problems here! So…I determined the problem was truly with the plug itself. I also jumped the two female connectors with a short piece of wire (simulating the switch) and the light would come on (as it should have). OK…plug problem confirmed!

    I cleaned the pins (both male and female), applied some dielectric compound and plugged it up. The light remained off for a few seconds…then started flickering…again! I could even hear a slight hissing sound coming from the plug (never a good sign…). I tried tweaking the male pins (bending them slightly…trying for a better connection)…No Joy.

    I clipped the wires (only the top two) from each end of the plug (red & white/black stripe wires coming from the latch).
    [​IMG]

    [​IMG]
    Using crimp connectors and two short pieces of wire, I made a connection that bypassed the original plug. I left the plug intact for the bottom two wires that control the opening of the latch mechanism! I used spade connectors on each wire so I could unplug it if needed for future service. Now it’s time to reinstall the latch and connect the wires! Everything worked perfectly!
    [​IMG]
    I cut two pieces of heat shrink tubing, unplugged the spade connectors and slid the tubing over the wire. Reconnected the spades and slid the tubing over the connection. I only shrank one end…which would allow me to unplug my new connector if needed (without cutting the protective tubing).
    [​IMG]
    Using the three bolts I reinstalled the latch assembly and secured my new wires and the original harness. I rechecked everything…and then reinstalled the plastic covers. Problem solved!
    [​IMG]

    Sorry for this post being so long and “painfully†detailed…but I do understand that not everyone has a high level of mechanical ability…and I wanted it to be easy to understand for those folks. Anyway…it took longer to write this than it did to do the actual repair (after I found the culprit!).
     
    Huddyl, scubaaid, tls1 and 7 others like this.
  2. koolingit

    koolingit Member

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    Great write up and great pictures.

    You've given me the incentive to finally look into my problem with the hatch. I have trouble getting the hatch to release on the first try. I'll squeeze the release handle and can hear the hatch release but it doesn't want to open. I always have to try two or three times. I'll be looking at the latch itself and that plug.

    Thanks again
     
  3. FlyboyTR

    FlyboyTR Member

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    Thanks! It could just be a lube thing...that would be easy! I hope you find your problem. :)
     
  4. tomlouie

    tomlouie Member

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    Thanks for the writeup! Twice we've had the problem where it thought the hatch was ajar even after we slammed the hatch shut. I'll look at the wiring you pointed out.
     
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Nice writeup and photos of your work.

    It's interesting that the wiring harness connector had a failure after only three years. Did you notice any moisture or corrosion evident in the hatch area, besides that particular connector?
     
  6. FlyboyTR

    FlyboyTR Member

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    Thanks Patrick.
    Nope...no evidence of any moisture or corrosion. Tire well is bone dry. I did note that there was no dielectric compound/grease in the connector. ...I thought that was odd...but really haven't looked at other connections in the Prius.
     
  7. FreydNot

    FreydNot Member

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    What is the benefit of leaving the two latch actuator wires in the old connector? All four pins of the connector look corroded in your picture. I would think the actuator will pull more current than the ajar switch which I would think would cause more problems. If I find the connector in a similar condition in my '08 I will be replacing all 4 pins of the factory connector with a new connector of some kind.
     
  8. FlyboyTR

    FlyboyTR Member

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    Actually there was no corrosion on the other two wires. There was some...smut...present, but it was from the two top Ajar Switch wires. The pins/plugs were ok. So, no need to change what isn't broke.:) ...plus, It was 95 degrees, 95% humidity, a huge thunderstorm was quickly approaching and I didn't have a 4-pin connector in the shop. :) Thanks for asking.
     
  9. dogfriend

    dogfriend Human - Animal Hybrid

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    I would suggest adding heat shrink tubing over the two butt connectors as added insurance against moisture. I also wonder if you might have a leak back there somewhere - maybe only evident just after a rainstorm?
     
  10. FlyboyTR

    FlyboyTR Member

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    There is no evidence of any water/moisture issues in/around the trunk/hatch/tire-well area. Considering the amount of rain we get here in Mobile, AL...checking after a rainstorm would be easy! :)

    Good thought on sealing the two butt connectors. I will do that...just in case! Thanks!:)
     
  11. Karah

    Karah Junior Member

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    I wonder if this is my issue & solution?

    I didn't have this problem before I sent my car to the mechanic. I needed to have the evaporator core replaced to fix the A/C & when I got the car back, the light comes on whether the car is on or off. I can no longer use my key fob because the car thinks a door is ajar, however I can drive it, thankfully! I did get a call from the mechanic asking me how to open my rear door. ( That was broken before I took the car in to the mechanic.) When I took it back, he said that it was probably because of the back door latch.

    They offered to fix it for me at an additional charge off course! I'm hoping to save a little bit from my big a/c repair expense & use this method to fix the door ajar light from coming on.
     
  12. leemcgee

    leemcgee Junior Member

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    Thank you very much for this older post Flyboy! I am a flyboy myself, 398 hours, more than a dozen GA airplane types, tailwheel, experimental and aerobatic. My 2007 Prius (430,000 miles!), now a salvage due to rear end collision damage, is two inches shorter on passenger side, has a similar door ajar light problem even though trunk latch closed. In my 2007, the two top wires are solid red and black/white, I assume these are the same wires?

    I am about to cut/splice them today to see if this works!!
     
  13. leemcgee

    leemcgee Junior Member

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  14. leemcgee

    leemcgee Junior Member

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    Cutting the two wires worked perfectly, no door ajar indication now, trunk latch works fine.

    Lee 2007 Prius 430,000 miles, salvage condition.
     
    jerrymildred likes this.
  15. scubaaid

    scubaaid New Member

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  16. scubaaid

    scubaaid New Member

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    Flyboy, First I would like to thank you for your post and pictures. I have a 2007 prius and you described everything to a T. Even the wires are the same color. My question is: I followed your instructions and the light came on again. I rechecked the connections and still the light stayed on. I unplugged the red wire, the light went off and I could lock and open the trunk as normal. Can I leave the red wire unplugged? what else would you suggest I do?
     
  17. Huddyl

    Huddyl Junior Member

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    Great writeup! This is a huge help for me - I have an '08 Prius with the 'door ajar' light always on, and I have some previous evidence that makes me think it's likely the hatch switch. Your post is going to save me a *lot* of time!