Confused on Towing Issue.

[frayed]

Towed my flatbed car trailer today (for my track car). The X5 went into "Tow Mode" according to the dash, which is what it told me when I tried to raise, then lower the X5 to aid in unhitching.

Did some searching and came across two article alluding to the system. One stated:

Trailer stability Control

Unique to the X5 is a new system that provides far greater safety and comfort when towing. BMW's trailer stability system recognises via a yaw rate signal any swerving action and in simple terms brakes the towing vehicle as well as the trailer itself (through an auxiliary brake system), returning the vehicle and the trailer to a stable driving condition.
A connection at the rear through the trailer hook up electrical socket informs the DSC system that the vehicle is towing. This signal activates the control system, which is programmed to intervene when necessary at a speed of more than 40 mph. Activation of trailer stability control is shown by the traction light flashing on and off.

Also:

The X5 all-wheel-drive system still has no transfer case, and it does not offer low-range gears. But it's loaded with more than enough electronic systems to keep a military contractor happy. There's ASC (Automatic Stability Control), DSC-X (Dynamic Stability Control), CBC (Cornering Brake Control), DBC (Dynamic Brake Control), ADB (Automatic Differential Brake), HBA (Hydraulic Brake Assistant) and HDC (Hill Descent Control). We don't have room to explain this alphabet soup, but trust us, it all works, and it all contributes significantly to the X5's outstanding handling. These systems can even detect when a trailer is hooked up and take appropriate action if the tail starts wagging the dog.

The powertrain and chassis made for stellar towing. After pulling a U-Haul trailer laden with his dismantled Lotus racing car back from Indianapolis, Gillies wrote: "This is a far better tow vehicle than the GMC Yukon XL Denali I used to take the Lotus to Indy (with the same kind of trailer). For one, you don't get blown around. For two, it just sits at 80 mph all day. Just because a vehicle can haul a house doesn't mean it can tow well. The BMW may not have a huge towing capacity, but it tows superbly."
Anderson recanted his earlier dismissal of the X5 as merely a tall wagon after using it to collect an impulse eBay Motors purchase from Sacramento, California: "Even with the 1972 BMW 2002tii riding piggyback, the X5 maintained 80 mph without breaking a sweat. Only in the high elevations of northern Nevada did it ever seem to struggle, searching for lower gears on long uphill sections. The X5 handles the trailer with ease, no jolting or wagging. It feels more like a train than a truck. If it weren't for the 2002 in the rear-view, I could forget we were pulling anything."

This last quote from Automobile magazine. . . I doubt these guys went to the trouble of putting in an aftermarket brake controller. And, BMW states a 6000lb tow capacity yet has no provision for an aftermarket brake controller. Accordingly, I'm questioning the need for a brake controller, particularly b/c I'm having trouble finding someone to install it.


1. Does tow mode brake the trailer if it has electric brakes?

2. If so, then why is an aux brake controller needed? I assume b/c braking during swaying is only that. . . it doesn't brake during normal braking.

3. If you install an aux brake control (e.g., prodigy) does it mess up tow mode's ability to brake the controller to reduce sway?

[frayed]

Just got off the phone with the dealer FWIW. . . sounds like the X5 does not have built in brake controller functionality. Shit.

[LI_BIMMER]

No much to offer here but curious of what the responses are.

What does the tow mode mean for towing? Are you saying no additional help other than it knows we are towing? Do we have to buy an additional component for the brake functionality?

I believe the 6,000 lbs is for 5 speed manual trans and 5,000 lbs for the automatic. I recalled reading this when I installed my BMW hitch.

[frayed]

The crazy thing is how the hell does bmw rate these suv's with 5000-6000lb tow capacity yet make it tough as nails to install an aftermarket brake controller???????

This is crazy.

Do they expect us to use surge brakes?

[JCL]

Originally Posted by LI_BIMMER

What does the tow mode mean for towing? Are you saying no additional help other than it knows we are towing? Do we have to buy an additional component for the brake functionality?

I believe the 6,000 lbs is for 5 speed manual trans and 5,000 lbs for the automatic. I recalled reading this when I installed my BMW hitch.

I believe the tow mode indication being referenced is if you have the air suspension, or some other option that I don't have on my 3.0. I don't get any indication that the vehicle is in tow mode. I do know that it is in tow mode, however, since the rear PDC is disabled when a trailer is connected.

5000 lbs is the limit for the auto trans and 3.0, up until 2003. Later models of the 3.0, and all the V8 models, have 6000 lb towing capacity.

[JCL]

Originally Posted by frayed

1. Does tow mode brake the trailer if it has electric brakes?

2. If so, then why is an aux brake controller needed? I assume b/c braking during swaying is only that. . . it doesn't brake during normal braking.

3. If you install an aux brake control (e.g., prodigy) does it mess up tow mode's ability to brake the controller to reduce sway?

I don't believe the towing module or DSC are interfaced to any aftermarket trailer brake controllers. I believe the trailer is braked by the vehicle, not by its own brakes (unless you have surge brakes).

The brake controller (required for electric brakes) is used whenever the vehicle brakes are applied, not just to reduce sway.

Jeff

[JCL]

Originally Posted by frayed

Do they expect us to use surge brakes?

Yes, or accept the liability yourself for installing an aftermarket trailer brake controller. I don't think they mind which one you choose, as long as it isn't their liability policy in play.

[frayed]

Originally Posted by JCL

Yes, or accept the liability yourself for installing an aftermarket trailer brake controller. I don't think they mind which one you choose, as long as it isn't their liability policy in play.

Man, that is lame. BMW produces a 6,000lb tow capacity vehicle and not only fails to support the proper electronics to tow that safely, but in fact uses an architecture that makes it a PITA to use an aftermarket device.

I talked with a trailer shop that will do it since the factory wiring harness is already installed.

[hayaku]

Originally Posted by JCL

I don't believe the towing module or DSC are interfaced to any aftermarket trailer brake controllers. I believe the trailer is braked by the vehicle, not by its own brakes (unless you have surge brakes).

The brake controller (required for electric brakes) is used whenever the vehicle brakes are applied, not just to reduce sway.

Jeff

Hey Jeff... sorry late to the game.. was busy moving and just got your pm today.

tow mode is only displayed and avail on x5's with full air suspension. it doesn't affect dsc or braking. it affects auto ride height.

dsc and braking are still controlled separately.

and as Jeff (JCL) has posted, yes you still need a brake controller and that doesn't control sway, but it will help control it if you do go into sway by slowing the rear down. thats why you need that lever bar on the prodigy or other controller to manually tweak the rear. otherwise the rear brakes only come on if you press the brake pedal.

[frayed]

Thanks all. I have a prodigy and the printouts from this forum. Hopefully the integration goes OK. I've grown to really like my X5, and that's coming from someone who has literally cycled through 8 cars in a few years. But this towing thing is annoying. Hopefully once installed and set up properly the brake controller and equalizer hitch setup become non issues.