Home
Caravan Lights Test Box
With a motor mover to get the caravan on and off the drive, I got concerned about stopping on the main road through our village and having the caravan moving, but disconnected from the car electrics, so no lights showing.
I know it is a big white box, and should be obvious, but I also know that there are a number of drivers that seem to interpret 30 mph differently to me!
I found online some trailer light test boxes, but they seemed from the descriptions I could find to be more like the network cable testers I've got, and will light up an individual circuit, or perhaps try and measure that there is resistance less than infinity, and more than a short circuit, and light up a status light. Useful, but not to try and provide some indication of what the caravan in the road is trying to do
After starting this project, I did find some videos on Youtube of others endeavours, like these: Trailer Lights Test Box and DIY Trailer Plug Light Tester Tutorial. I took some of the ideas on board, but made it my own.
Lights and sockets
Being a caravan based on an entry level model, it hasn't got quite all the bells and whistles that some have. I know that some 2018 models have usb charging ports in the corner spot lights and stuff. I fancied having somewhere to charge phones and tablets on the front shelf, so did some investigating.
Sargent Electrical, who make the PSU and control panels for our Swift caravan have some schematics on their website in the support section. Looking through the Swift Group 2016 PDF, it shows that the 12v sockets are connected to the E4 connector on the PSU, with a wire that is Yellow with a white trace / strip.
The caravan handbook suggested that there are some spare outputs on fuse 9 and 10 which also might be possible to use, but no details of what connections they might be on the PSU.
Fortunately, in my efforts to get the Swift Command remote control app to program heating to work with the Truma blown air system, I'd also got a copy of the Sargent Electrical EC600 systems dealer technical guide. This details all the pins on all the sockets on the PSU, along with their associated fuses. Fuse 9 & 10 have their outlets on the E1 connector.
When it all goes wrong
I really wasn't planning to write this as my next article. I'd planned on doing something about the awning and things I'd made for it.
Anyhow, what happens when things go wrong. Let's start by borrowing from Douglas Adams. Don't Panic
For us it was getting our van off our driveway for a weekend away at Easter.
All the normal checks had been done.
- Towball cleaned
- Mirrors fitted
- Noseweight checked
- All doors / windows closed/locked
- Legs raised
- Caravan attached
- Lights checked
- ....
But as we started to pull forward, there was a horrible metallic grating sound, like a leg had been forgotten and was dragging on the driveway.
This distracted us from making the tight turn off of our driveway, and without waiting for my wife who was watching, I started the turn about 15 cm too soon.
The rear drivers side awning rail was caught on a bolt sticking out from the gatepost. There is the smallest mark on the sidewall from the bolt too
With the awning rail snagged on the bolt, it bent and tore the rear GRP panel, detaching the grab handle and light cluster too.
I stopped as soon as my wife said so, as by then it was on my blind side.
Dropping the caravan where it was, I moved the tow car so we only blocked one lane (the tow ball was at about the white line)
As we wondered about how we were going to shift 1.5 tonnes of caravan out of the road, a passing BMW driver stopped and offered to lend a hand pushing back on the driveway.
Weight Issues
So last time I shared the specs of the weights of the caravan. Weight and caravans is an important thing. Caravan organisations recommend keeping the caravan as less than 85% of the tow car's weight. Otherwise you are more likely to have the caravan cause control or stability issues to the tow car.
3 weights are given. Mass in running order (MRO) which is the weight of the caravan, without anything extra. Basically what you would expect it to weigh when towing it from the showroom on the day you bought it.
Payload is the amount you are allowed to load into the van before it is considered overloaded.
Maximum Technically Permitted Laden Mass (MTPLM) is how heavy you are allowed to make the caravan by adding things to it. It is the sum of its MIRO with user payload.
So with these numbers in mind, and using the 85% guideline, an ideal weight for a tow car would be around about 1700kg.
And this is the next thing that made life potentially difficult. Driving licenses.
Hannah and I both passed our tests after the changes in 1997, which then no longer automatically gave people in UK the license to drive 17 seater minibuses, 7.5T trucks or a car and trailer that have a combined "train weight" (that is the sum of car and caravan weights) of over 3.5T.
According to the government:
Licences issued from 1 January 1997
If you passed your car driving test on or after 1 January 1997 you can:
-
drive a car or van up to 3,500kg maximum authorised mass (MAM) towing a trailer of up to 750kg MAM
-
tow a trailer over 750kg MAM as long as the combined MAM of the trailer and towing vehicle is no more than 3,500kg
Here comes the next number. MAM. That is the maximum weight that a vehicle can weigh. The same as the MTPLM of the caravan. But here is the snag. It isn't what the car / caravan combination currently weigh, but what the maximum the could weigh.
Long story short, Hannah and I both had to go and take a car + trailer (B + E) test.
We used a driving schools car, as our tow car is an auto, and the other catch that there is with licenses is with a normal B license, if you take a B + E test in an auto, you are only allowed to tow a train weigh of over 3.5 T in an auto!
