US Gear Unified Tow Brake For Hummer H3

[Injun Joe]

09 Safari Cheetah and 08 Hummer H3 are the two parts to this puzzle.

My research indicates I should go with the Unified system since the Hummer H3 has an electric not a vacuum brake system.

Does anyone have this or similar system and any comments? Thanks.

[Jeff_S]

The Unified Tow Brake System will pull down on the brake pedal via a selenoid, so that's the same action as your foot.

However, the UTBS also includes a vacuum pump that is added to the vacuum line going to the brake booster under the hood. That pump is energized any time the UTBS is activated. Therefore, the UTBS is truly applying "power assisted" brakes each time, and the selenoid's work is reduced.

If the H3 is electrically boosted, I guess you would want to power that booster instead of the vacuum pump. Whether that is possible, I do not know.

Additionally, the towed vehicle should have a constant +12VDC from the coach, so that operation of the vacuum pump does not drain the vehicle battery.

Here is a diagram of the whole UTBS layout.

I think I found the answer!

UTBS Installation Supplement for GM vehicles with factory installed vacuum pump/electronic check valve on Power Brake Booster
.

[wa8yxm]

The vacuum pump on the US-gear system can be omitted if you don't need it.. it should be possible to wire the Hummer's brake booster system so it's always live (Are you sure it's electric?)

Or, if the brake booster works with the ignition off, You are good to go with the US-Gear system.

As for keeping the towed battery charged.. US-Gear already thought of that and a 40 amp "Tie Line" between the chassis battery and the towed battery is already part of the design

DO upgrade the ground lead though.. Most light cables do not have nearly enough ground on 'em.

[Jeff_S]

Injun Joe,

Though I wasn't incorrect earlier, here's a better answer ...

Looks like the UTH-1000 is specifically for electric-hydro boosted vehicles.

So, US Gear should has your situation covered.

It's great not having to move a braking device out of the vehicle every time you disconnect. The only extra action the UTBS takes is to replace the breakaway switch key that is cabled to the coach with a stand-alone key so you can drive away.

[two-niner]

Jeff-S: How about a little more info on the "stand alone key". Sounds interesting.

Kerry

[Injun Joe]

I talked to a local installer about this product and we determined that this is the appropriate kit: Unified Tow Brake Towed Vehicle Kit (TVH-1000K) Electric Hydro-boost Operating and Installation Instructions

It is the TVH-1000K which will work with the Hummer system and also with the Monaco pre-wiring setup in the coach.

I still have to look in to the break-away key.

By the way, none of this towing business is cheap, especially if one has to buy the tow bar (Aventa LX), Blue Ox base plate, wiring, Unified Tow Brake, labor, etc.
Newbies, like me, should be prepared to cough up some serious coin, or possibly buy used components. Ain't RVing fun?

Thanks to all for the great advice.

[Jeff_S]

Originally Posted by two-niner

Jeff-S: How about a little more info on the "stand alone key". Sounds interesting.

Not THAT interesting.

The key for the breakaway switch when towing is attached to a long cable that attaches to the coach. When unhooking the vehicle, the breakaway switch key is removed (temporarily activating the Unified Tow Brake) and is replace with a key that has nothing attached to it. The "standalone" key is merely to keep the breakaway switch open for normal driving of the vehicle.

I lied, there is a split ring on the standalone breakaway key to pull on when removing it to connect up to the coach.

I believe both keys came with the Unified Tow Brake, one key on the cable, and one standalone key.

[hardy1000]

Originally Posted by Injun Joe

09 Safari Cheetah and 08 Hummer H3 are the two parts to this puzzle.

My research indicates I should go with the Unified system since the Hummer H3 has an electric not a vacuum brake system.

Does anyone have this or similar system and any comments? Thanks.

Call Unified they will fix you up

[wa8yxm]

Originally Posted by two-niner

Jeff-S: How about a little more info on the "stand alone key". Sounds interesting.

Kerry

I will give you two answers

The short answer is this: The break-a-way "key" (Or plug) that goes into the swith is nothign more than a piece of plastic, Shaped to fit and do the job. WIth a ring in it and a cable attached

The "Stand alone key" is an identical piece of plastic, with a ring in it, and no cable attached.

The long answer: Or what is inside that switch box

This is not exactly how it's buit but it works for a description

Imagine if you will a plastic cloths pin. Now on the "Tip" end of this cloths pin drill a hole through both "Arms" of the pin.. Open the pin and run a screw up through the hole to the threads are on the outside of the pin, apply washer, nut washer, wire, nut. When the pin is closed the two screws should touch.. You now have the "Guts" of a break-away switch

The plastic goes into the "Jaws" of the pin, forcing the two screws apart.. Pull it out and the spring snaps the jaws shut, closing the circuit and grounding the break-a-way lead activating the brakes.

NOTE: this is not exactly how it's built.. but the concept is identical.

IN either case the "Drive off" key or "Stand Alone" key is identical to the break-a-way plug

ALternative.. I put a clip on the end of the cable and leave the plug in place both ways.. This is easier.. but more dangerous cause once when I pulled the plug for testing I found the very simply almost no way it can fail switch.....failed.

[two-niner]

Hey' my 06 Grand Vitara came equiped with all that. I did not know it was called a stand alone key. No manual.
Last year I bought two of them(keys) at Quartzsite for $2.99 each.
Another mystery solved!!

Kerry