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 Post subject: Re: curt echo brake controller needs 7 pin wiring kit?
PostPosted: Fri Jul 05, 2019 3:48 am 

Joined: Sun Sep 27, 2015 11:26 pm
Posts: 296
Hi Savage,

Thanks for the chart I will keep it handy. I watched the video and it all looks pretty simple. The unit has a 10 amp fuse, but the video does not suggest wiring it to the aux/power socket in the rear of the RAV4 EV because it might draw more and damage the wiring harness.

I don't quite understand why it would draw more, unless it is related to the wiring length of the trailer light kit in combination with the aux/power socket wiring harness length?

The fuse for that aux/power socket is 15 amps, but the fuse is shared with the middle aux/ power socket in the rav4 ev. The only aux/power socket with a dedicated 15 amp fuse is the front socket next to the passenger. The instructional PDF for the unit seems to say in total the lights draw almost 9 amps. Unless I read that wrong and is more. Should I even consider wiring it to the aux/power socket even though wiring lengths will increase in total?


Maximum amperage:
Stop/turn lights: 2.1 amps per circuit
Tail lights: 4.2 amps per circuit

About how much amps is the unit going to draw during operation. I keep thinking it could be ok to wire it to the aux/power socket back there since the unit comes with a 10 amp fuse and the rav4 ev uses a 15 amp fuse. I'd guess just be careful with what you plug into both the aux sockets since the line is now shared. I guess the unit is on all the time regardles of use. I'd guess when no trailer is towing behind the unit itself uses way less energy than when towing and using the trailer lights?

 Post subject: Re: curt echo brake controller needs 7 pin wiring kit?
PostPosted: Fri Jul 05, 2019 4:37 pm 

Joined: Mon Aug 07, 2017 4:55 pm
Posts: 245
Location: Duvall, Wash.
Those specs are the maximum for that converter, but if you're smart your trailer will have LED tail & stop lights, just the like the RAV4 and pretty much all modern stuff these days, and the trailer's lights (including marker lamps) won't draw half that much. That's why I said I'd look hard at using the cigar lighter socket for power.

If you think you'll actually be using near 10A on trailer lights, then I'd run a dedicated wire from the front, but if unless you're going with incandescent lamps -- and a lot of them -- I'd think using the OEM cigar lighter circuit will be adequate.

If you think you'll be running, say, a Peltier thermocooler off that socket at the same time your towing, that might be a good reason to run a dedicated wire. That wouldn't be an unusual situation for camping.


Back in the day, I used to construct my own European-to-US tail/stop/brake converters for my cars: four Schottky diodes is all that's required, if powered by the tow vehicle's existing lighting circuits. I could use standard diodes, but the 0.7v forward voltage drop made the trailer's light just a tad dimmer than they had to be. Back in those days, you had to swap in a different flasher relay when you towed, or the lights would flash too fast when the trailer was connected -- all the OEM flasher relays' timing was based a thermal unit on a bimetal strip and required a certain lighting load for the flasher timing to work out correct: change the lighting load, change the flash rate. Then electric flasher relays became affordable and that problem went away, with the side effect that you could no longer know you had a turn sig lamp burnt out by noticing the remaining lamp flashing too fast.

Now that many modern vehicles monitor lighting circuit power draw in order to illuminate a warning lamp that there's a lamp "burned out", adding trailer wiring sometimes requires a bit more thought.

Later, I had an '89 Aerostar with factory tow package that I had to reverse-engineer one day, and Ford's package had a lovely bank of three relays to isolate the van's lighting power supply from the trailer, with the unfortunate side-effect of occasionally blowing a very well hidden and hard to access fuse, about once a year I had to tear out panels to get at it until I replaced it with a circuit breaker. It was also a completely deactivated relay module until activated but a feedback loop in the factory tow adapter harness, which was unobtanium at the time, and which I reproduced using the wiring diagram from Ford that had a misteak. Lots of fun! Then two other later Aerostars with variations on that theme, which I extensively documented about six years ago . . .

For my own reference, and the search engines: Ford Aerostar tow wiring: three eras and versions.

Al Savage
2014 Rav4 EV, Shoreline Blue Pearl, #2609, first use 04Jun2014, 49k miles (Aug2017), OpenEVSE 40A. First DU replacement May2018 59k.
2018 Model 3 LR AWD, blue. 9.6kw solar
1999 E300 on B100 (sold Sep2018)

 Post subject: Re: curt echo brake controller needs 7 pin wiring kit?
PostPosted: Wed Jul 10, 2019 2:04 am 

Joined: Mon May 19, 2014 4:49 am
Posts: 626
Location: Ithaca, NY
Im sorry but I didnt read the whole thread.

I have been towing with my Rav regularly since I bought it new in 2014. Ive towed A LOT!! If you havent heard of me you can check out my youtube channel You can see my builds..

Last year I installed a very cool and very small brake controller. I made a video about it. Here is the link.

I currently tow a 2300lb range extending camper that I built. I call it T-Rex V2. It extends the range of my car and gives me a place to sleep. It works great. I just got it out of the paint shop and Ill have another video shortly. Basically, it tows like it isnt even there. The Rav ev is awesome. I love it!

2014 Rav EV #3364
2012 Plug in Prius

OpenEVSE builds
Dual voltage, portable 40amp Openevse

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