plain OM

Where and how would one install an electric trailer brake controller on a late model Forester?

In my current towing vehicle (76 Suburban), the controller is mounted on the lower side of the (metal) dashboard to the left of the steering column. The main 12 V power was taken from a junction box on the engine side of the firewall, and the trailer brake supply wire was routed from the controller, through the firewall, down to the left chassis rail and out to the back where it joined the lighting wiring and the main connector (fastened to the rear bumper).

Given that Subaru requires trailer brakes when towing over 1000 pounds, in addition to the Subaru OEM trailer hitch and lighting wiring harness, does Subaru have a guide for installing the brake controller? Alternatively, is there an commonly-accepted way to install it?

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07 OBW NA 4EAT

Wheatridger

Its a real challenge to fit a brake controller into the limited underdash space. I was bashing my knee into my Prodigy when it was anywhere left of the steering column. Finally I squeezed it into the space to the right of the steering column. I had to bend the rectangular steel mounting bracket into an arched shape that roughly conformed to the bottom of the dash, about six inches below and forward of the keys. Now, it's found a permanent home, and it helps me keep my vacation home, a 16-foot Scamp travel trailer, safely behind me.

efelker

Wheatridger -- Do you have a pix of the installation? What about the wiring?
Is there a connector already under the dash, or did you have to run your own under the hood?

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2006 FXT Obsidian Black Automatic

nate

This is a little bit off-topic for the Electronic & Interior forum and it's probably sort of a newb question but then I am a newb when it comes to towing. Why does SOA require trailer brakes for towing more than 1000 lbs?
I can think of 3 possibilities but there are probably more:
1) Limited braking force of standard Forester brakes
2) Relatively small size/wheelbase of a Forester
3) Just good towing practice in general

If it's #1 a brake upgrade should help.
If it's #2 the Legacy/Outback/B9 should have different recommendation
If it's #3 then virtually every trailer would come with brakes standard

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'04 FXT M/T Java Black Pearl

plain OM

Thread Starter

nate:

I think you are correct in your analysis. But this is not a fault of, nor unique to, the Forester. In my current quest for a new car I have found that virtually all manufacturers of similar weight/size vehicles require trailer brakes in order to tow over 1000 pounds. In fact, the user manuals for light trucks (e.g. pick-ups) and heavier SUVs with even higher tow capacities refer to the use of trailer brakes when towing over 1000 pounds.

It’s my understanding that many if not all US states require the use of trailer brakes on trailers over 1000 pounds GVW regardless of the tow vehicle capacity. Even when I bought my tent trailer in 1991, American RV trailer manufacturers were including brakes on new trailers (whether recreational or utility) of over 1000 pounds GVW. Of course, it’s up to the user to equip their tow vehicle with the necessary system to properly activate the trailer brakes.

The Forester could probably stop an unbraked 2000 pound trailer, but at what cost to wear and tear on the braking system, the frame and, most important, overall safety. In a long, slow reduction of speed it shouldn’t be too much of a problem, but for more accentuated slow-downs or stops, 2000 pounds pushing a 3000 pound vehicle from behind would seem like a rather good candidate for control problems and jack-knifing. Upgrading the tow vehicle braking system does not address these dynamic factors. In fact it would seem that the better the brakes on the tow vehicle, the more pressure the unbraked trailer will put on it.

Interestingly, the Legacy and the Outback have a higher rated towing capacity than the Forester. (Both are a bit heavier than the Forester.) However, the maximum tongue weight is the same in all three cases, about 200 pounds. There’s a standard formula that says the tongue weight should be about 10 percent of the trailer GVW. I understand that this is primarily for optimum trailer handling characteristics. If the maximum tongue weight is 200 pounds, then the maximum GVW of the trailer should be about 2000 pounds. I’m not sure how Subaru comes up with the higher trailer GVW ratings.

As far as I can tell, Subarus do not have any provisions in the wiring to connect up a trailer brake controller. My original post sought ideas on how to do this, including how to route the wiring to the trailer. Still looking for this.

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07 OBW NA 4EAT

vavrath

Found this generic wiring description on the internet. Not sure if this is what you're looking for:

http://www.etrailer.com/faq/brakecontrol.asp

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2002 Forester 2.0 XQ manual transmission

plain OM

Thread Starter

Vavrath:

That's a great site -- the explanation is quite clear. In regard to Foresters, however, I'm wondering where the battery power (paragraph 4) would be connected, and how or where to run the trailer brake wire from the controller to the back of the car (paragraph 1). From what I've seen elsewhere, the Subaru trailer wring connector that is preinstalled in the cargo area only deals with lighting. So there has to be another wire run to the back. This would also require an additional connector for the brake. I really would like to find out how this is all done.

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07 OBW NA 4EAT

vavrath

Battery power shouldn't be a problem I think. The 12-pin (not the 7 pin) trailer connectors that are available for Subarus have a permanent "+" and "-", which is available as long as the car is having power. If your trailer has only a 7-pin connector (so essentially no foglight on the trailer), there are converter plugs from 12 to 7-pin (not vice versa of course). For the breake pedal I guess you'll have to run a wire to the back of the car. No other option. There is a wiring diagram supplied in the hitch manual if you purchase an original Subaru hitch.

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2002 Forester 2.0 XQ manual transmission

hank

Why?

Think worst case, a need for a panic stop downhill (in front of you a vehicle just dropped a refrigerator off its tailgate, or someone's Airstream just came off its trailer hitch, did a polevault when the hitch dug into the asphalt and landed on its back across all three lanes.

I've seen both of these happen ahead of me in going on 40 years of driving. I wasn't towing anything at the time ....

With trailer brakes, your trailer is not only going to be trying to stay behind you, it's going to be slowing down well enough that it may be helping you slow down too. And if you have to go off the highway to avoid a collision, it's at least behaving. Otherwise it's trying to do its own unstable nose-stand on your hitch and is likely to come off, or over the top of your vehicle as you try to maneuver suddenly.

James

I have been looking for a place to mount my Prodigy. I think I have found a much better place, that is more out of the way. I mounted in the opening for the fuse cover. I know this isn't the prefect place, but it is great if you only need the controller now and then because I can easily remove it and put the fuse cover back.



I made two bars (I used scrap from work so excuse the look and the extra holes). The short one is 90 mm and I made two counter sunk holes 6 mm in from the ends. I also drilled two through holes that will attach the mounting bracket that came with the prodigy. The bracket has long slots the these hole positions don't really matter. The longer bar length is not so important (I made mine 100 mm), but the holes need to line up. All four holes in the long bar are threaded M4.



The two bars will sandwich two plastic tabs at the top of the opening. These are bolted with flat heads. The other two bolts go through the Prodigy bracket, the short bar and thread into the long bar.



This image shows the two tabs that I attach to. Note the square hole is an existing hole, and I drilled a second hole that lines up with my bars. You can't see it, but there are a couple of "wings" behind these two tabs, but there is space enough that the long bar slips in just fine.



This is the two bars attached. I can put the original cover back on, and no one would be the wiser.



And now with the Prodigy bracket...



Just screw the Prodigy in place and Viola! I still have to do the wiring, but the controller is in easy reach (for me at least) without really leaning over. When I am not using the Prodigy I just un-screw it, Un-plug it and un-bolt the prodigy bracket. I can leave the two bars and pop the fuse cover in. The only drawback is that the prodigy covers some of the fuses, although I shouldn't need to be in there much and it is easy to remove.

Just a side Note, the prodigy slip in holder was too wide for this opening. I would have had to cut into the plastic to get it to fit.

James

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07 Forester 2.5X EAT SE
09 Mercedes B200 Premium

Hardrvin

It seems like your prodigy is mounting w/ an upward tilt...does it have any problems w/ that? As I recall, they only "like" being level or slightly downward.

James

The instructions for the prodigy say to install it between level 0 degrees or up to 70 degrees tilted upwards. Never downwards.

http://www.tekonsha.com/instructions...89_H%20web.pdf

Other brake controllers may be different.

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07 Forester 2.5X EAT SE
09 Mercedes B200 Premium