| linusMDX |
| Not sure what is going on, but just dropped it off at the dealer....Any of you guys have this issue? |
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| eurohazard |
Does the 3rd brake light work? If it does, then it's safe to say the brake light switch at the brake pedal is functional.
If only the 2 tail light brakes lights are out, then I don't know. At least the dealership will figure it out. Knock on plood. |
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| linusMDX |
What all works:
*Third center light
*Parking Lights
*Turn Signals
Hope they can figure it out :( |
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| lawboy02 |
| I know this may sound strange, but did you check the bulbs? I have previously had both of my tailights go out at the exact same time or close enough together so that I thought it occurred at the same time. Maybe it is a simple fix. |
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| linusMDX |
| I did not open the case up and check, but looked from the outside..It seemed like they were not blown...but then again..I really could not tell... |
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| squaw_ski_bum |
Check the sensor that detects if a bulb is burned out . It is clipped to the inside of the left rear finish panel that runs from the rear hatch to the 2nd row seat.
It is a pain in the butt to get this panel out, you have to take out the rear trim inside the hatch, the storage compartment, the jack/tool set, the left side 3rd row seat, the left 3rd row seatbelt upper anchor, cargo net anchors, etc. As I recall you'll need Torx drivers and a socket wrench set. The service manual really helped. A good chore to let the dealer deal with if you're still in warranty.
I had to replace the 2nd row seatbelt that my son had left hanging out the door, it rubbed on the tire and got trashed. So I had to pull out the finish panel to replace the belt assembly, and when I put it back together I forgot to plug the wires back on to the sensor. The next day my wife was driving the MDX and I happened to be following her and I noticed no brake lights on L & R though the upper 3rd light worked. No dash indicator of a bulb out. Oops... |
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| linusMDX |
| What does the sensor look like? I pulled the side panneling off, which was a serious pain, but I did not notice anything disconnected. I did however notice something clipped onto the side behind the panneling on the second row. Will see what the dealer says when I drop it off. Thanks for the info! |
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| linusMDX |
Hi,
I just took the rear seat and left side panneling off, but can't seem to see this sensor that you were talking about. Would you happen to have a picture, or an exact location? The clip that I saw was for the door sensor. If I take it to the dealer with all the panneling off, you think they would say that I voided the warranty? |
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| linusMDX |
| Problem fixed! I found the brake sensor, which is behind the driver's side rear pannel where you put the head rests in for storage. It was all the way at the bottom, and it was attached to the plastic pannel. Thanks so much for the tips! |
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| squaw_ski_bum |
On my 2002 it is a small square box about 1.5" x 1.5" x 1" with a couple of tabs on it and a 5 wire or so connector. It is clipped to the inside of the left rear interior trim panel, below the compartment that holds the jack and lugnut wrench. This is from memory, reminded by the drawings in the shop manual and for a 2002 so it may be different on your MDX.
the service manual says the wires are BLK, WHT/GRN, YEL, WHT/BLK, and GRN.
Looking at the schematic, YEL is +12 from the battery (through fuse 9 under driver side dash.) BLK is ground. WHT/BLK is from the brake pedal switch, +12 when the pedal is pressed. GRN goes to the L and R brake lights. WHT/GRN goes to the brake lamp indicator on the dash.
Power to the lights goes through the sensor module - WHT/BLK goes through a resistor to GRN to the L and R bulbs, what the sensor does is look for the proper amount of current by looking at the voltage across the resistor. When a failure is detected it turns on a transistor to sink current through the dash indicator light to ground (WHT/GRN is an open-collector output.)
According the the schematic a failure in the high mount brake bulbs will not be detected, only the L and R bulbs.
As I understand it, your symptoms are:
1) both L and R brake lights are not working, but high mount brake light works. This means the fuse is good.
2) L & R bulbs are ok,
3) the brake light indicator on the dash does not stay lit when the key is turned on.
There are only a couple of possibilities, and suggested diagnoses (at your own risk of course):
a) The brake light dash indicator bulb is out and both L and R brake lights are out. This is unlikely, but easy to test. Turn the key from off to on. All the dash indicator lights come on then go off so you can tell if the dash indicator bulb is good. If the dash light is out then replace it and check the L & R brake light bulbs. If the dash indicator is ok then go to the next step.
b) The sensor is either faulty or unplugged. Check the connector to the sensor, make sure it is plugged in. If it is plugged in and still doesn't work, then unplug it and jump the WHT/BLK to GRN on the connector and see if the L & R brake lights work when the pedal is pressed. If this works then then you have a bad sensor. If you think the sensor is bad, check for continuity between the pins on the sensor for WHT/BLK and GRN. It should be very low resistance - a guess is .050 ohms. If it is open (high resistance) then the sensor is bad.
c) Both L & R bulbs are out and there is a break in the WHT/GRN wire to the dash indicator. Jump the WHT/GRN on the connector to BLK. The dash indicator bulb should stay on (assuming the bulb comes on then goes off when the key is turned on so you know the bulb is good.) If it does not then check that BLK is connected to GND. Look for a break in either WHT/GRN or BLK as appropriate, and check the L & R bulbs.
d) There is a break in the WHT/BLK wire to the sensor. If step b) didn't work then check for +12 on the WHT/BLK wire when the brake pedal is pressed with the key on. If you don't get +12V then there is a break in the WHT/BLK wire somewhere.
Hope this helps. |
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| squaw_ski_bum |
| I just posted a long diagnostic procedure and while I was typing it you posted that you found it and have it fixed. Oh well! Was the connector loose? Glad I could help. |
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| linusMDX |
| WOW!..That is an AWESOME write-up!..I wish I saw it sooner :)..Yeah..I was sitting there just looking at the big mess that I made with all the panels and seats out. After scratching my head for about 45 mins, I looked down at the panel that I removed and there it was! What happened was that the previous owner had the rear seat belt replaced, and the sensor was unplugged. I am so glad that I found it, cause I am sure the dealer would charge me for that..I was soooooooooo down all weekend, since I did not know what the problem was. I was so scared that I had a serious electrical issue. Anyways..Thanks again for you help. It is great to know that there are folks out there that are willing to help out with such great detail. Thanks!:2: :4: |
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| squaw_ski_bum |
No problem, happy to help. This is a great forum.
I highly recommend a copy of the service manual (search the forums for how / where to order), it has saved me much more than it cost in both $ and time. |
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