getting power to electric brakes

[Darwin Maring]

Originally Posted by MJo

I purchased electric brakes, after being told that I had a 7 wire connection on my Volvo brake package. Turns out that I only have 4 wire so Scamp had a 7 wire trailer to 4 wire car connector so that I was able to get home with all the lights I needed, but no electric brakes. Can I give the electric brakes power without having to rewire the whole trailer package on my Volvo? (add a wire from a constant on light on the rear of my Volvo and thread it in to 7 wire trailer?).

Am I to understand that you picked up your Scamp at the factory and they did not explain things to you?

[stevebaz]

you need one of these installed on your car. it plugs into your 4 wire system and then you add the necessary connections to make you car 7 pin with brake controller and charge lines to your battery. Takes someone who knows what their doing.

https://www.etrailer.com/Wiring/Tow-Ready/30717.html

[gordon2]

Originally Posted by thrifty bill

Given the discussion thus far, OP would be well served by an in-person visit to someone who can walk her through the system and address any missing components.

Except for this little issue called COVID. But if I may misquote you...

Originally Posted by thrifty bill

... everything can be solved on the internet.

Zoom to the rescue! If someone would video chat online the OP could do a walk through and show the components.. that would likely answer most questions in mere minutes.

My guess is also that there is an Autowbrake brand controller which is either connected to the trailer battery for brake power (which is bad), or not connected to a source of brake power at all (worse).

[MJo]

I wondered about that, using power from a tail light. of course it couldn’t be a turn signal light or a stop light. Have to look at it. My Volvo doesn’t have a license plate light or I could use that power source. no problem if it’s connected to the trailer battery because the trailer battery is charged when the car is running.

[Darwin Maring]

Originally Posted by MJo

I wondered about that, using power from a tail light. of course it couldn’t be a turn signal light or a stop light. Have to look at it. My Volvo doesn’t have a license plate light or I could use that power source. no problem if it’s connected to the trailer battery because the trailer battery is charged when the car is running.

You have to have a lisense plate light. It is the law.
Now, Depending on the wattage required, the lisense plate light wire might be to thin.

License plate light sometimes is just a clear lense in a tail light. When the red is on some white light shines out a clear lense.

[Glenn Baglo]

Hire a competent shop to wire it correctly, and even replace that brake controller that Scamp sold you, if necessary.

[gordon2]

Originally Posted by MJo

... My Volvo doesn’t have a license plate light or I could use that power source. no problem if it’s connected to the trailer battery because the trailer battery is charged when the car is running.

Please dont do either of those things.

Tapping onto the vehicle lights can cause problems in many ways. The added power use can confuse the vehicle's computer, blow fuses, result in voltage drop, etc. The wiring for the lights is designed by electrical engineers to power the lights.. not some brakes on a separate vehicle.

And using the trailer's battery to power the brakes might work for awhile, but there is no guarantee that the battery will always have enough charge to safely use the trailer's brakes. I promise you when you most need the trailer's brakes is exactly when the battery will not have enough power. Do you really want to have partial power when an emergency stop is required to prevent a collision?

But the tow vehicles battery and alternator will always supply enough power to the brakes when the vehicle is running (assuming proper wiring to the trailer). By wiring the brake power connection from the brake controller to the tow vehicle battery you have full power from the battery AND the alternator (when veh is running). A self-resetting circuit breaker on that line is also called for in case there is an temporary overload or short circuit.. Then the circuit will be protected but when the breaker resets you have functional brakes again.

I second the motion to find a good trailer shop and pay them to make it right.

[John in Santa Cruz]

Originally Posted by nigeleccleston

I also had Scamp install the AuTowbrake when they replaced the axle (with 10 inch brakes) on my Scamp 13. They hooked up the wireless unit to the power supply from my battery. Which runs down the battery as told above.
I changed the wiring so that power comes from the tail light wire. The AoTowbrake manual has instructions for doing this. It does mean that you have to have the lights on as you drive.

6 amps for 2 10" brakes is more current than most tail light circuits can handle. typical pre-LED tail light was 2 amps, LED ones are much less than 1 amp.

[John in Santa Cruz]

Originally Posted by MJo

no problem if it’s connected to the trailer battery because the trailer battery is charged when the car is running.

uh, how is your trailer battery getting charged with a 4 pin hookup?

[k corbin]

It is impossible to remote diagnose this issue this way as the OP does not know, recognize or understand what they own so can not communicate what needs to be known to resolve it. Acquiring an understanding of what a person is looking at for a trailer brake system when starting from ground zero of knowledge takes some time and some research. It is not acquired in a few brief conversations. There are too many variations of brake systems and wiring options.

[Darwin Maring]

Originally Posted by k corbin

It is impossible to remote diagnose this issue this way as the OP does not know, recognize or understand what they own so can not communicate what needs to be known to resolve it. Acquiring an understanding of what a person is looking at for a trailer brake system when starting from ground zero of knowledge takes some time and some research. It is not acquired in a few brief conversations. There are too many variations of brake systems and wiring options.

This thread has run its course. An expert in camper wiring and in teaching the owner is required to solve these issues.

[Lynn Eberhardt]

This has gotten way too complicated. You have four wires going to the trailer - you need five. The fifth would be power from your car to the trailer battery. That will not only make sure your trailer brakes will work but will mean you have a charged battery upon arrival at your next campsite. The most convenient solution is to mount a seven pin connector on your car that matches your Scamp plug. You can leave the additional two pins un-wired.

[gordon2]

Originally Posted by Lynn Eberhardt

This has gotten way too complicated. You have four wires going to the trailer - you need five. The fifth would be power from your car to the trailer battery. That will not only make sure your trailer brakes will work but will mean you have a charged battery upon arrival at your next campsite. ...

Sharing a single power source to charge the trailer battery AND power the trailer brakes? Here's the problem with that... in the case that the trailer battery is heavily discharged (like it might after a few days of boondocking), then when you start to drive away the discharged battery will in effect be sucking most of the power from that single wire... whatever is left for the brakes will be reduced and since the battery is also discharged the brakes will not have full power. So I would do as all the experts say... run a seperate 10 gauge wire from the tow vehicle battery to the brake controller's brake power (magnet) connection. Use a self-resetting 12 volt circuit breaker at the tug battery. That way the alternator (via the battery connection) will be sure to provide full power for the brakes any time the tow vehicle is running.

Now if you want an optional charge line to the trailer battery thats fine.. just use seperate wire so you're not robbing the brakes of some of the available power.

4 wires for lights. 5 for lights and brakes. 6 for lights, brakes and charge line.

[stevebaz]

Originally Posted by John in Santa Cruz

6 amps for 2 10" brakes is more current than most tail light circuits can handle. typical pre-LED tail light was 2 amps, LED ones are much less than 1 amp.

you could use the lamp light to switch a relay carrying the current needed but it complicates things. there's more than one way to skin the cat.

[bigangelman]

If interested I have the trailer end of the wiring and a wireless brake control, both brand new. I decided not to use them when I found out how much the wiring on my tow vehicle was going to cost. It's big enough I don't really need trailer brakes with the small trailer and large van tow vehicle.
Lmk

[MJo]

thank you. I already purchased one, a week or so someone told me how to find one, but there must be someone else out there with the same problem, keep looking. thanks anyway, MJo