Page 2 of 2 FirstFirst 1 2
Results 26 to 49 of 49
  1. #26
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    1,631
    Sorry for not replying earlier - I was on vacation.

    On the PDC - I turn it off. There isn't much else to do about it. I put on the rack and take it off only when I'm using it.

    I didn't know about "trailer mode" - I'll investigate that. Now that you mention it, I do have a thing that plugs into the two inch receiver that is an LED light that turns on with the brake lights. I used to use that on our old Volvo XC90 to keep the electrical connections clean. I'm wondering if that would not solve both problems - the car would think there were bulbs there and it would be in trailer mode. I could just throw it in the storage compartment plugged in and the problem would be solved.

    The other solution that would be a little more work but would solve it for sure would be to take a trailer plug and solder resistors between the connection for the brake lights to simulate the filaments of the bulbs. If you got the values right, it would fool the computer into thinking that there is a trailer with functioning bulbs there. Then just unplug it when you're done.

    Apparently, you have to have the car programmed to pull a trailer so that it knows to deactivate the rear PDC and the traction control when a trailer is attached. Presuming that is done and you have some sort of light or resistor plug attached, the car would think that it has a trailer attached and behave accordingly. I suppose if road conditions got dicey enough (probably wouldn't be backing up at least), you could just disconnect the plug and get the traction control back.


    J.

  2. #27
    mtbr member
    Reputation:
    Join Date
    Jul 2011
    Posts
    94
    no worries!

    there is a trailer mode...when you get an oem hitch, they reflash the computer...but for the car to recognize a trailer it has be plugged into the outlet as you suggested

    the adapter you're speaking of should tell the car there is a trailer attached, but then you'll get a bulb out error

    the whole thing is pretty frustrating...

  3. #28
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    1,631
    I think not. If you have a resistor in for each tail light lead, the with that adaptor in place the computer will think it has a working bulb out there. That's all a bulb is essentially, is a resistor.

    J.

  4. #29
    mtbr member
    Reputation:
    Join Date
    Jul 2011
    Posts
    94
    would you mind describing your set up in more detail? ohms etc?

    Quote Originally Posted by JohnJ80 View Post
    I think not. If you have a resistor in for each tail light lead, the with that adaptor in place the computer will think it has a working bulb out there. That's all a bulb is essentially, is a resistor.

    J.

  5. #30
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    1,631
    It can't be that hard. I haven't done it yet but am going to.

    Get a typical bulb and use an ohm meter to measure the resistance through the bulb. Get a three resistors the same value at about 1W or 10W each (bigger the better). Or get whatever the wattage of the bulb is.

    Get a wiring harness tail from the hardware store. Solder the tails of all three resistors together one end. Connect this to the white wire. Then connect one of the remaining tails to each of the green, yellow and brown wires. Plug it in and see. Should work. You might have to play with the values a little bit.

    Here's the connection on the trailer side so you know what you are hooking up.

    Rack suggestions needed for BMW X5-qu5059_800.jpg

    J.

  6. #31
    mtbr member
    Reputation:
    Join Date
    Jul 2011
    Posts
    94
    Not that simple either...there is an after market adapter that has 100ohm resistors designed to work with trailers with led lights. The problem is that it is not enough resistance. If you start messing with different value it creates too much heat.

  7. #32
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    1,631

    Rack suggestions needed for BMW X5

    If you add more resistance it will be cooler because it will need less current. Is that what you meant? All you need to do is heat sink the resistors to a chink of aluminum and it will be cool. I'm sure this will work at some level.

    What does BMW say.? They must have something for this.

  8. #33
    mtbr member
    Reputation:
    Join Date
    Jul 2011
    Posts
    94
    my intro electrical engineering class fails me now...

    bmw has nothing to say...the shop foreman at my dealer was clueless and the corporate monkeys had no idea what i was talking about

  9. #34
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    1,631
    I'm an electrical engineer.

    Worst case, just hook up bulbs to all those connections. A properly sized resistor = a bulb. If the resistor gets too hot, heat sync it. For that matter, you could take the resistors (i'd get the big square ceramic ones) and mount them to the rack somehow - it would be a perfect heat sink.

    Actually, what ought to work really well, is get small tail lights and mount them to the rack so they mirror your actual tail lights. That would help make sure no one rear ends you.

    J.

  10. #35
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    192
    For resistors search for "LED load resistor" or "taillight load resistor" at your favorite online shopping destination, buy three, wire them up like JohnJ80 mentioned above. The resistors will get hot, so watch where you mount them. That should work to "trick" the car into thinking you have a trailer connected.

  11. #36
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    1,631
    Quote Originally Posted by mtbikerTi View Post
    For resistors search for "LED load resistor" or "taillight load resistor" at your favorite online shopping destination, buy three, wire them up like JohnJ80 mentioned above. The resistors will get hot, so watch where you mount them. That should work to "trick" the car into thinking you have a trailer connected.
    Thanks for finding those resistors. Here's one I found:

    Tail Light Load Resistor Kit | Flashers & Load Resistors | Car Bulb Installation Supplies | LED Car Bulbs | Super Bright LEDs

    These would make sense to stick to rack with a thermal adhesive compound. Then bring the tail back to the car and connect it to the trailer hitch connection and you'd be good. The rack would make a great heat sink and it would be right there when you need to hook up the rack.

    J.

  12. #37
    mtbr member
    Reputation:
    Join Date
    Jul 2011
    Posts
    94
    this should be a piece of cake for you then. looks like a pretty elegant fix has been found. thanks for your insight!

    2013 BMW x5 - Trailer hitch recommendations? - Page 7 - Bimmerfest - BMW Forums


    Quote Originally Posted by JohnJ80 View Post
    I'm an electrical engineer.

    Worst case, just hook up bulbs to all those connections. A properly sized resistor = a bulb. If the resistor gets too hot, heat sync it. For that matter, you could take the resistors (i'd get the big square ceramic ones) and mount them to the rack somehow - it would be a perfect heat sink.

    Actually, what ought to work really well, is get small tail lights and mount them to the rack so they mirror your actual tail lights. That would help make sure no one rear ends you.

    J.

  13. #38
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    1,631
    That is a great find! And I'm sure it will work. It's basically what I was saying but this guy has figured out the values of the resistors and the wattage rating. Perfect!

    Is that what you are going to do?

    I have a hitch what was installed aftermarket and just has the 4 pin flat tail that connects to the trailer. No big deal to make the same piece to fit to that. I haven't dug into the more than in a cursory sense yet since I only needed the rack. I will now though since you brought this issue up. Next time I take it in for service, I'll make sure it's programmed for a trailer in the onboard computer.

    J.

  14. #39
    mtbr member
    Reputation:
    Join Date
    Jul 2011
    Posts
    94
    i should have all the parts on monday...the resistors were actually a little tricky to locate...called a few radio shacks and the guys were clueless so i just ordered from fry's online...ordered a curt 7 way round connector.

    i'll let you know how it goes. apparently there isn't that much space so you have to remove some of the plastic in the connector. i bot 2 sets just in case i mess it up.

    so sick of the bulb out warning!

  15. #40
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    1,631
    Really interested in this. Please do let us know.

    The X5 is kind of a perfect vehicle for this sort of thing.

    J.

  16. #41
    mtbr member
    Reputation:
    Join Date
    Jul 2011
    Posts
    94
    so i put together the adapter with the resistors. for $6 and 10 minutes you can fix a stupid problem on your german luxury vehicle. seems to work. problem solved.

  17. #42
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    192
    You can also buy them from digikey, they offer relatively low price shipping as well.

    One thing I would recommend is to get something more than a 5 watt resistor, as at 12v (and 33Ω resistor) you'll be pushing about 4.3 watts, however at 14 volts (which is where most vehicles operate while running) you'll be at about 6 watts. So a 5 watt resistor may be fine, but it would probably be a good idea to go to a 10 watt or better resistor.

  18. #43
    mtbr member
    Reputation:
    Join Date
    Jul 2011
    Posts
    94
    i'm no electrical engineer...i only play one on bike forums

  19. #44
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    1,631
    Quote Originally Posted by wlhighlight View Post
    so i put together the adapter with the resistors. for $6 and 10 minutes you can fix a stupid problem on your german luxury vehicle. seems to work. problem solved.

  20. #45
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    1,631
    Quote Originally Posted by wlhighlight View Post
    i'm no electrical engineer...i only play one on bike forums
    LOL. Glad it worked (couldn't see why it wouldn't).

    J.

  21. #46
    Did I catch a niner?
    Reputation: Mr Pink57's Avatar
    Join Date
    Jul 2009
    Posts
    2,387
    For the trailer mode, I would look at a trailer light to attch to the rack and just plug it in when using a rack. That way you have a red safety light with the rack. I think some are magnetic or you could easily adhere one.

    When not using my hitch (Honda Element) I have a red light in.
    Mr. Krabs: Is it true, Squidward? Is it hilarious?
    https://www.dollarshaveclub.com/ref/...A0CC/s/tx/cx/1

  22. #47
    mtbr member
    Reputation:
    Join Date
    Mar 2009
    Posts
    1
    I hate bringing up old threads, but I stumbled upon it via a Google search so I hope to help others with this update. A new thread would have been redundant.

    I am not sure which brand hitch I have, but I know it isn't the thousand dollar OEM one. It came with the X5 when I bought it used. Whoever installed it had to trim the rear bumper. When I installed the aero kit, I had to dremel a small portion of the center piece. The aftermarket hitches I see listed exclude the X5M. I have seen hitches for the M model so there may be a specific model. If you want a hitch rack, it's probably the way to go.

    When we travel with bikes and want to keep them secure and dry, I made an interior platform using Yakima Blockhead fork mounts. Realistically, I can move both fork mounts to the driver side and fold down the 60% portion of the middle row and have space for a third occupant in the 40% portion.

    I go into further detail here: custom interior bike rack - Xoutpost.com

    Rack suggestions needed for BMW X5-20140309_165507_1024.jpg
    Rack suggestions needed for BMW X5-20140309_170604_1024.jpgRack suggestions needed for BMW X5-20140309_170622_1024.jpgRack suggestions needed for BMW X5-20140309_170718_1024.jpgRack suggestions needed for BMW X5-20140309_170831_1024.jpgRack suggestions needed for BMW X5-20140322_210952.jpg

  23. #48
    I Tried Them ALL... Moderator
    Reputation: Zachariah's Avatar
    Join Date
    Dec 2007
    Posts
    4,573
    Nice X5M OP.....I just traded mine in for a 2009 Porsche Cayenne Turbo S
    "The mind will quit....well before the body does"

  24. #49
    mtbr member
    Reputation:
    Join Date
    Mar 2012
    Posts
    289
    If that was my SUV I would definitely do a nice hitch cut into the bumper cover as above. Get a 1up USA rack and you are in business. The last thing I would want inside a nice SUV is a muddy MTB
    Epic Flash Boris F65X + road bikes

Page 2 of 2 FirstFirst 1 2

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •