Tow connector

[upallnight]

What type of connector is everyone using to convert the round electrical trailer connector to a 4 pin flat connector?

[upallnight]

Never mind, just found the original part number for the round to flat connector.

61130412965

[Robert Platt Bell]

The Westfalia hitch kit from BMW included the adapter.

A more interesting trick was how to wire the brake controller....

[TiAgX5]

Originally Posted by Robert Platt Bell

The Westfalia hitch kit from BMW included the adapter.....

and there's even a storage spot for the adapter to the left of the spare tire.

[NJP]

You guys know how it works the stability control when is connected to the trailer ?

[Robert Platt Bell]

Originally Posted by NJP

You guys know how it works the stability control when is connected to the trailer ?

It works just fine. Like I said, it makes a great tow vehicle. Good control, very stable, and even corners nicely. Of course, it pays to have the trailer properly balanced, with at least 10-15% of the weight on the tongue.

The trailer brakes are electronic (on an RV, most boat trailers use hydraulic surge brakes) and are not affected by the ASC.

The only caveat I have heard or read about is that using a load-equalizing hitch sometimes confuses the load leveling control (air bag suspension). My car doesn't have the air bag suspension, and from what I read in these forums, I am grateful for that.

Some manufacturers (Chrysler) offer "trailer anti-sway control" which uses the ASC to dampen trailer sway, should it occur. I've been in a situation like that before (trying to tow a large trailer with a Toyota pickup) and it is like trying to fly an airplane with an aft CG. Whatever input you try to make is 180 degrees out of phase, making things worse.

Fortunately computers can do what humans can't, and supposedly that anti-sway control will dampen out oscillations like that. I don't know if BMW offers that. They don't seem to be promoting the tow capacities of their vehicles much. The new X5's don't even have a cutout in the bumper for a hitch.

[NJP]

Thanks for your information Robert .

[TerminatorX5]

Mine did not come with an adapter for the factory hitch (lost in previous ownerships), so I got myself an aftermarket one from a parts store, with little LEDs for whatever "check-the-light" purpose...

when i connected that thing to the car connector, the load of the LEDs told the trailer module that there is a trailer, and that disabled the rear PDC, and also prevented the air suspension from going up or down with the push of the button - i got a message in the cluster, saying " TRAILER MODE"...

unfortunately, the LEDs did not provide adequate load for the trailer module, as the module would "lose" the trailer and then "find" it again - the resistance of the LEDs was right on the brink of recognition of the load by the module...

So, I think if I built a little circuit consisting of a couple of appropriate value resistors, I might be able to use the adapter in "lieu" of the trailer in those rare cases when I hook up a bike carrier or a cargo carrier to the hitch... And thus, can back up without that annoying PDC noise from the rear...

[JCL]

The tow mode (called Trailer Stability Control by BMW) is part of the Dynamic Stability Control (DSC) module, and is simply another algorithm in the black box, which detects accelerations consistent with trailer sway, in combination with the steering angle sensor. It applies vehicle service brakes independently to dampen out the sway, but does not communicate with the trailer brakes.

When DSC intervenes (ie on snow) the light comes on on the dash, so you know it is working. In many miles of towing, including through the Rockies on snow covered roads, I have never had the DSC show any sign of activation for trailer sway. It could be working without indication, but I don't think so. I think it is more likely that it is a nanny system, always there in the background, but not doing anything actively under normal circumstances. The good towing manners of the X5 are due to the short rear overhang (very short axle to hitch ball distance), the competent X5 suspension, the relatively low profile vehicle tires, and having sufficient tongue weight on the trailer (10-15%).

The stability systems aren't built by BMW, they are Continental or Bosch in most cases. Both now offer active trailer braking in their stability control modules, and the US truck manufacturers are now using those versions. They activate more often on pickup trucks, given the typically long rear overhangs, poor front/rear vehicle weight distribution, and higher profile tires.