View Full Version : VR3 Bumper Guard - Back Up Sensor

09-09-2014, 04:38 AM
These went on sale a few years ago on Amazon - like $10 each - so I got 2. They have since been discontinued but are readily available on Ebay, usually about $20 each, sometimes as little as $5.

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR0.TRC0.H0.XvR3+bumpe r+guard&_nkw=vR3+bumper+guard&_sacat=0


I installed the first one on my other D - and used it for about 4 years - happily.

It's a back up sensor that detects objects through the rear bumper, no drilling little circles etc. It's not as good as a back up camera, nor does it work as well as the back up sensor in your new BMW - but it does work pretty well and can pay for itself many times over if it only triggers once. Don't know if I would have actually hit anything it sensed, but it did a good job of keeping me out of any potential trouble.

It works by sensing changes in the magnetic/electrical field surrounding a length of adhesive metallic tape that mounts inside the rear fascia. It's an invisible installation, but you may have to drill 1 hole in the underbody.

To install, you have to remove both rear taillights to install the tape/antenna. Also remove the carbon canister and cover, and the rear carpeted bulkhead board and triangular cover over the idle controller box. I realized my car was already in this configuration today so I went ahead and did most of the install of my second VR3 on the other D.

The tape goes inside the rear fascia. I have mounted mine just above the impact absorber onto the rear fascia - if you look at the fascia you will find a silver/grey section of fascia just above the black and below the taillights that comes up vertically about half an inch high - I mount the tape to the inside of the fascia along that line. You will need to first get some simple green or similar and clean that area of the inside of the fascia to within an inch of its life. You can reach in toward centerline behind the licence plate by reaching in from the left and right.

Once your paper towels start coming out clean, go at it again with rubbing alcohol on a clean paper towel. Then peel loose the first 6" of backing paper from the adhesive on the tape and position the end with the spade connector attached to the inside of the fascia on the drivers side, starting from the corner. Then unroll the rest of the tape with backing paper attached across the inside of the fascia, behind the license plate, and out the passenger taillight opening - making sure it does not twist. The tape will be running below the taillight openings on the inside of the fascia.

Pull off the backing paper working your way to the passenger side, pausing mid way across the passenger taillight opening. Now cut the tape to length, peel of the rest of the backing and press it in place.

You may have a hole drilled already from the left pontoon into through the fascia support, if not, drill a 3/8" or so hole through near the antenna mounting bolts by drilling from the rear of the car, through the fascia support - and then into the pontoon by the electric antenna.

The next component is the logic box. It is only slightly larger than a box of matches and has a molex connector for the wiring and a 18" wire with a spade connector to hook to the antenna tape. Put the controller box inside the left pontoon, and push the single wire through the new hole into the rear fascia, and plug it onto the connector on the end of the antenna tape.

The last component is a wiring harness that has a molex connector with 4 wires, two of which are already connected to a piezo buzzer, the other two are black and red. Black goes to any good ground, and red has to hook up to the reverse light circuit. Two ways to do this. The kit comes with tapcons and connectors and you can tie the red and black wires to the reverse wire at the taillights connector and ground, or route them over into the relay compartment and hook them up there.

To complete the installation place the piezo in the cavity near the idle speed controller , and push the molex connector through the rear firewall along with your antenna wire and into the left pontoon, reach through from the pontoon opening and pull the molex connector back until it is long enough to mate with the logic box. Plug it in, dress your wires and then mount the logic box inside the pontoon in a location of your liking using the attached double sided tape - I mounted mine to the antenna bracket assembly after cleaning that surface thoroughly.

If you are connecting the red and black wires to the taillight harness, pull those two wires through into the pontoon, and then push them through the hole with the antenna wire into the rear fascia. The red wire ties to the reverse wire (Green Brown?) using the tapcon and the black ties to the board ground (Black?). Double check the colors.

If you prefer to tap in inside the car, do not pull red and black into the pontoon, instead dress them behind the rear trim board over into the relay area on the passenger side of the car. Black ties to ground (note you can also find ground right by the idle speed controller if you prefer). Red ties to the reverse wire where it loops from the red bulkhead connector to the black bulkhead connector - the Green/Brown wire.

I have not completed this step on this second install as my passenger door is locked closed but good - will deal with that soon.

After you dress and label any wires, button up the taillights, the vacuum canister, and the rear bulkhead board. Mount the piezo near the idle speed controller - even under the carpet and plywood board it is plenty loud enough.

The logic box takes about a half a second to power up and self calibrate, and it only turns on when you are in reverse. The result is that you shift to reverse, and less than a second later the piezo gives one short beep to let you know its ready. This is especially helpful in a 5 speed when you let a friend drive - you can always tell easily when they have properly found reverse. In an auto it will not have time to fully power up and beep if you shift relatively quickly to Drive, so again you should only hear it when you shift intentionally into reverse.

After the unit calibrates and beeps, the unit will beep whenever the magnetic field near the antenna tape changes - the range is about 30-36". If you start the car and there is already an obstacle 2" from the rear bumper - it probably won't register the delta in time to warn you - but 99% of the time it works perfectly. It may also trigger when you are backing from a steep driveway onto a level street, the sensor can read the approaching street as though it was a curb and it still beeps, but that beep can save your muffler tips none the less.

Again - this is not quire as nice as a factory sensor - but given the price and the ease of installation - it's well worth the money. To be honest if I had to buy another one for this D I might have spent $100 - but they go for much less. Install is pretty quick and easy - and the one in my old car still worked perfectly the day I shipped it away - probably 4 years of service.

It's totally invisible and requires only modest wiring molestation (probably tap cons unless you like to solder) and perhaps drilling 1 invisible hole. You could mount it in a concours car and the only evidence would be the piezo speaker hidden near the idle speed box, and you could hide that better if you had to. It's a nice little addition.

10-12-2014, 05:06 PM
I finally completed the installation today - works great.

While it may be easier to tie the red wire from the kit into the reverse wire inside the fascia at the tail light board, that is exposed to the elements so I prefer not to. Instead I ran a line to the relay compartment - and behind the rear bulkhead board you can fine a Green/Brown wire coming out of the red bulkhead connector. This wire loops the signal from the transmission switch into the bulkhead area and back out into the rear lighting harness. As its inside the car I'd prefer to have the connection there - but either way works.

Cheap date for a modern feature, not hard to install. If anyone needs a video of the system working let me know.

BTW my wire over to the controller is independently fused. I also installed an auto dimming rear view mirror with Homelink that requires a reverse signal, both are tied to that same green brown wire with a 5 amp fuse in between so as to not blow out the reverse lights if something goes wrong with my additions. I also recommend labeling your new wires and fuse - even if you remember, it will help the new owner in 50 years.

10-13-2014, 11:26 PM
it will help the new owner in 50 years.

We will have flying cars by then, so he/she may want to upgrade the system by 2064. :elmo2:

Excellent write up too!

Was considering getting something like this, but decided I should be fine without one.

10-14-2014, 05:24 PM
We will have flying cars by then, so he/she may want to upgrade the system by 2064. :elmo2:

Excellent write up too!

Was considering getting something like this, but decided I should be fine without one.

It as a no brainer for me - I already owned it, had the rear fascia open and had to wire in the reverse signal for the mirror anyway. Cheap date though. Anyone curious might just grab one cheap on ebay to install when the stars align for them like they just did for me.

04-09-2015, 01:41 PM
This is very good to know. I found them not on eBay, but did a search and found them on Overstock.com http://www.overstock.com/Electronics/VR3-VRPS100-Bumper-Guard-Back-Up-Alarm/6030511/product.html


Looks like I'll be getting on as backing up the D is an exercise in patience.


edit: Looks like they're out of stock.. :(

04-09-2015, 02:07 PM
Just got one on Amazon for $26 bucks!