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Toyota Sienna Electrical Problems



  • My problem was that on a 2000 Sienna the dome lights and door locks quit working and the headlights would only come on with the engine running (or maybe key on-don't remember exactly). (Note here--I checked and rechecked fuses. Also my dash clock was working. The clock and dome lights are on the same fuse on the 2000 model.) After rolling this around in my mind for probably a couple of months I realized that these 3 things all had timer functions. The dome and headlights will turn off after a while when unattended and the doors will relock after a time when unlocked with the remote. I figured that they all must intersect somewhere.

    I'm a pretty good problem solver & I was afraid of what a shop diagnosis of electrical problems could cost so I started asking questions of every mechanic I could find. No one wanted to help except for one friend who was willing to print out a basic wiring diagram. I finally went to a Toyota dealership and asked the shop foreman if I could examine some wiring diagrams. He pulled the book and we looked at the individual diagrams for each of the systems with problems. There was a common element on all 3--the INTEGRATION RELAY. This might more appropriately be called a "relay integration module." This device is 2 linked circuit boards that essentially tell all the relays what to do. On the 2000 model Sienna it is in a (+/-) 2.5" X 1.5" X 5" plastic case mounted on the back side of the fuse block under the dashboard. On some cars it is integrally built into the fuse block but on this car it is a replaceable unit.

    I learned that there is no way to test this part. Often technicians try to locate an identical part on another car and use it to test the system and see if that’s the problem. I checked with the Parts Department and learned that the new part was about $430! I started looking for a good salvage yard. I found one with the used part in stock for about $100. I went home and pulled and reinstalled the fuse block to see if I could actually do it. I was successful so I drove to the salvage yard and pulled the unit, popped in the replacement part, and suddenly all was right in the world. By the way—it was a good thing I pulled the part out before committing to a replacement. The part number the Toyota place gave me was not the same as on my part. I needed the actual number from my part to match the part at the salvage yard.

    I hope this helps someone.
  • I have a 01 Sienna with an electrical Gremlin. Power door has a mind of its own, have been unable to get fixed because the dealer can't fix unless it sees the problem, which happens with no rhyme or reason.

    My issue I would like help with is the dash lights. The light that illuminates the Right side and center of display (speed odometer and fuel gauge) is not illuminated in addition to the Air flow selector in the center console. This makes it difficult at night. The controls all work they are just not illuminated. I looked at the fuses and there does not seem to be one that operates just these 2 lights. Also the cigarette lighter doesn't work either but that is not as much of a concern since I do not smoke.
  • eric55eric55 Posts: 2
    2008 Sienna Limited AWD. 9000 miles. Dead. No power to dash, dome lights, head lights or anything. Doesn't "click" with the key. Meter on the battery says it has 12.7 volts. It drove fine just an hour prior to attempting to start it.

    I measure the 12.7 volts at the main power bar in the fuse box under the hood, so it leaves the battery. There must be a main fuse or relay that delivers it to EVERYWHERE else. I can't find it.

    Anybody have any clues? BTW, I am in the country of Turkey and can't readily get to the, or any, US dealer where I purchased the car. I am sure it is in warranty, but no help there. Nothing to help me out at the Toyota website either.
  • eric55eric55 Posts: 2
    Found my own problem. I was looking too hard. When shipping a vehicle overseas, the transport company disconnects the battery. When reconnecting the battery in my van, they put the positive cable on tight, but the negative just tight enough to make contact. Over the course of the past year, the nut gradually loosened until yesterday when it lost all contact leaving no return path to the battery. Previously contact would intermittantly be lost causing the Sienna's dashboard clock to reset to 1 AM with no dicernable pattern. I am rather relieved and my clock problem is fixed also.
  • ateixeiraateixeira Posts: 72,587
    Phew, you dodged a bullet there. Glad to hear it's fine.
  • hoppinghopping Posts: 1
    2008 Sienna loses all power. Battery seems to be dead. Battery charger brings it back to life. This has happened several times usually after driving at night with lights, A/C, radio, wipers etc. all on.. First the dealer said it was the battery and replaced it. The dealer said the rear door will not drain the battery. (I sometimes leave it up with the interior lights turned off.) - all was well for a month and then same problem.

    This time dealer said it was due to rear door being left open even though the interior lights are switched off at the dashboard. The dealer said the rear door drains .5 amp even though the lights are turned off. He said it had to do with the computer trying to talk to the door or something like that.

    Does anyone know if this is true?
  • ateixeiraateixeira Posts: 72,587
    Not sure but I have heard something like that, i.e. that lights left on have killed the battery.

    I always lock the doors and make sure the lights turn off. If any door is open you get a beeping, so you know to go back and check which door isn't completely shut.
  • yatesjoyatesjo Posts: 186
    We always park the van in the garage so we don't bother locking it and have been lax about closing doors. We figured the lights shut off on their own so no problem.

    If my wife isn't going out much during the week and the van is left open for a few days the battery is drained. It happened to her twice so now we are careful to get all the doors closed. Doesn't make any sense to me why the doors drain so much power without any lights on.
  • ateixeiraateixeira Posts: 72,587
    Didn't think about the garage. Yeah, I have a car port so it's always locked.
  • tomd8tomd8 Posts: 8
    I have the same problem with my radio. It will display when turn on and then no display later but radio is still working. I have to turn off the radio then turn back on to get the display again. I was wondering did you fix your problem. Thanks.
  • hershghershg Posts: 2
    No, but, this sounds crazy, rapping your knuckles on the display when the radio gets into a bad state seems to "fix" it.
  • It sounds like you need to replace the light bulbs in the dash. It is not that hard. There are about 3 screws that you have to take out, one to the left of the steering, look up, and 2 over by the radio, in which you have to pull the plastic off there. Then the rest of the dash pops out. Then you will remove 4 screws to the display. The light bulbs that light the display are the large green screws like fixtures. The bulbs are haligens that pull out of the fixtures. There are 4 bulbs total for this area. The Air flow area is a bit more tricky. You have to remove the screws for control area, the dash will already be out of your way if you do both at the same time. There are 3 bulbs, smaller, in this area. The little push button switches have their own bulbs that you have to purchase at the dealer. The other bulbs you can buy at any auto parts store and at wal mart. Let me know if you have any trouble with this and I will be glad to help.
  • My 2005 Sienna's inside lights stopped working in the van- except the front ones - but none work any longer when doors open.
    Husband tried fuse - it is ok.
    Any other ideas?
  • All other lights work. The 10 amp fuse under the steering wheel blows immediately when I put in a new fuse.

    Any advice on what to look for or change?
  • ateixeiraateixeira Posts: 72,587
    There must be a short in the wiring that goes to that light.

    Take it (the taillight) out and clean it up, see if there's any dampness there. Check the bulb itself as well.

    I'm far from an electrical expert but I had a radio that kept doing that, and the solution was to replace the radio.
  • ccity1ccity1 Posts: 1
    My front speakers blew out a few months ago... It wasn't a volume issue, they just slowly - and seperately - chose to go... I had them replaced, and soon after my radio decided to work sometimes and then cut out (although the display stays on as if it is working fine).

    But now I can't get any sound at all (though still the same situation with the display) ... The radio 1 and 2 fuses behind the ashtray are fine... could the amp be blown?
  • wwestwwest Posts: 10,706
    That might mean you had DC, Direct Current, flowing through the speakers as the amp was in the process of failing.
  • So over the past year or so, my wife and I have noticed a problem with the radio volume. Occasionally, the volume will increase on its own and can not be turned down using the knob on the radio itself. You must use the volume control on the steering wheel. The dealership can not duplicate the problem and says that they've checked all the wiring and it seems to be hooked up correctly. I've talked to others in the waiting room at the dealership with the same issue and results. Any suggestions on how to go about fixing this problem?
  • I have a 2000 sienna and the problem started about a year ago, when I would turn my headlights on with the switch ob the column, I got nothing, but if I turned it back one click they would turn on fully, i just did not have any bright lights,but then all of a sudden it stopped working out of the blue.... the headlights do not come on at all......what do I do???
  • I have a 2004 sienna and the lights in the rear dont go on when opening the power door but only on the passengers side . When I open the doors on the drivers side they work fine .. Any idea what that is all about ??
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