I have power to the socket, when i put the plug in there is power to the plug but no fridge on 12v and no atc light. Any ideas please. Lunar Delta TI & Nissan Elgrand.
ATC & FRIDGE not working
- Thread starter GrahamDerby
- Start date
Starting with the obvious, have you checked for loose or corroded pins? Are you on a 13 pin system? Using an adaptor? Most caravan repair places and tow bar fitters have a light board that they plug you into, very often gives out the fault straight away.
I had a similar issue on my 2010 model van from new, no ATC fitted but fridge wouldnt work. There was some sort of adjustable relay in the towbar setup that wasnt giving out enough amps. It had worked fine on the van previous but this one seemed to need a higher ampage. Anyway, after plugging into to their lightboard, the dealer simply turned up this relay and all was fine.
I had a similar issue on my 2010 model van from new, no ATC fitted but fridge wouldnt work. There was some sort of adjustable relay in the towbar setup that wasnt giving out enough amps. It had worked fine on the van previous but this one seemed to need a higher ampage. Anyway, after plugging into to their lightboard, the dealer simply turned up this relay and all was fine.
Thanks Thingy for that , its a 13 pin and i have put a tester and power is getting through the plug and the pins are ok, i was wondering if a wire had broken in the cable from the plug to the van ?
Graham
double check ALL the earth's in the plug sockets and their final earth connection to the caravan and car.
double check ALL the earth's in the plug sockets and their final earth connection to the caravan and car.
Has it just stopped working or is it a new combo. If you are in Derby ish, Id be happy to hook mine to it and vice versa, see if there is any difference.
Relays don't "give out" amps,they switch amps and the relay in question is not adjustable,it either works or doesn,t work.
In this case the obvious problem is one of resistance in the coil circuit,preventing the relay from energising (switching on).
It may well work with a light board - how do you "turn up a relay" sounds like a load of eye wash to me.
Clearly there is a problem with your plug/socket that is introducing a resistance preventing operation of you ATC and fridge.
Look for dirty pins and sockets and failing that check wiring connections are good and sound.
In this case the obvious problem is one of resistance in the coil circuit,preventing the relay from energising (switching on).
It may well work with a light board - how do you "turn up a relay" sounds like a load of eye wash to me.
Clearly there is a problem with your plug/socket that is introducing a resistance preventing operation of you ATC and fridge.
Look for dirty pins and sockets and failing that check wiring connections are good and sound.
Damian
Moderator
bertieboy1 said:
You are right, they don't "give out" amps, nor do they switch amps, they are VOLTAGE regulated relays and ARE adjustable for the switching voltage.
Many are set too high and "chatter" when the fridge tries to draw power and need the switching voltage lowering to negate the voltage drop as the fridge kicks in, which is why most have an adjuster built in.
However, from the OP posting I am not sure if this is a sudden fault or one which has been present for a while, if sudden, and IF the ATC is on the same circuit as the fridge (which it should not be) then first to check is fuses, and there are more than one fuse usually.
Some voltage sensitive relays can indeed be adjusted, the adjustment is for the pull in and drop out voltage.
However this relay is only for the fridge and in a roundabout way the charging for the battery. The fridge has its own two pins feed and return.
The ATC however requires a PERMANENT supply and again has its own feed and return, this feed also supplies the caravan battery charge, but is inhibited by the "habitation "relay located in the caravan.
On same caravans the fridge also requires a caravan battery feed to supply the fridge light and control board, this feed is required for all 3 fuel sources.
However this relay is only for the fridge and in a roundabout way the charging for the battery. The fridge has its own two pins feed and return.
The ATC however requires a PERMANENT supply and again has its own feed and return, this feed also supplies the caravan battery charge, but is inhibited by the "habitation "relay located in the caravan.
On same caravans the fridge also requires a caravan battery feed to supply the fridge light and control board, this feed is required for all 3 fuel sources.
I'm afraid Damien's conception of a relay is quite wrong,it does switch amps - with it's contacts,that is the primary function of a relay.
Also unless the relay is an "auto ranging" type the coil will be rated at a fixed voltage,in this case 12 volts.The current a relay coil takes is very small and it doesn't take much resistance to stop the relay pulling in (operating).
Being aware of the cheapness of the caravan industry the relay will just be a standard relay with a 12 volt rated coil.
Also unless the relay is an "auto ranging" type the coil will be rated at a fixed voltage,in this case 12 volts.The current a relay coil takes is very small and it doesn't take much resistance to stop the relay pulling in (operating).
Being aware of the cheapness of the caravan industry the relay will just be a standard relay with a 12 volt rated coil.
Damian
Moderator
Quote " I'm afraid Damien's conception of a relay is quite wrong,it does switch amps - with it's contacts,that is the primary function of a relay"
Of course Amps are part of the situation, as we all know, but the relay from the car is voltage regulated, normally to switch at 14v, but as soon as the fridge draws power, the voltage drops and the relay cuts out.(Normally because the wiring is not big enough to suit the purpose)
So, the adjusting screw that I altered to allow the relay to switch at 13v does not exist then,,,,,,,,,,,,,but it does, and it works.
Of course Amps are part of the situation, as we all know, but the relay from the car is voltage regulated, normally to switch at 14v, but as soon as the fridge draws power, the voltage drops and the relay cuts out.(Normally because the wiring is not big enough to suit the purpose)
So, the adjusting screw that I altered to allow the relay to switch at 13v does not exist then,,,,,,,,,,,,,but it does, and it works.
What a complete misunderstanding of basic electrics.bertieboy1 said:
"12V" is just a nominal figure covering anything from 9-15V - Voltage Sensitive Relays (VSRs) monitor the input voltage and switch at the set level - some are adjustable, some have fixed cut-in/cut-out voltage settings.
Relays are rated in both voltage and current capacities, but I don't really understand why anyone is nit picking on whether the contacts switch current or not.
Its probably more correct to say the contacts switch power.
I think Bertie is referring to the habitation relay?
Which is a reed relay on my Bailey, actually there is more than one all mounted on a pcb board.
I have never had to change one so they are reliable.
Its probably more correct to say the contacts switch power.
I think Bertie is referring to the habitation relay?
Which is a reed relay on my Bailey, actually there is more than one all mounted on a pcb board.
I have never had to change one so they are reliable.
bertieboy1 said:
Because the alternator is regulated a VSR is used.
On older cars these work very effectively.
On smart charging systems such as mine on my CX-5 the alternator voltage is regulated depending on what CURRENT is being drawn from the battery.
For example if lots of electrical systems are used headlights for example then the alternator voltage is increased, that's actually one way round getting a modern car to effectively pull in the cars VSR.
Hi Thingy, I do live in Allestree but am at present in Chapel St Leonards on holiday, i will be back in about 3 weeks so if i can't fix it i may take you up on your offer of a hook up. Cheers G
We are off tomorrow for a couple of weeks (Longleat first then New Forest) , well be back last week October. Just send me a pm is you need to try this.
xtrailman said:
I'm sorry but that is also wrong.
Once turning and active the alternator output is fixed at 14.4V or thereabouts and does not change. Adding load - such as the headlights - simply puts more load on the engine the speed of which may dip slightly as a result, but so long as the alternator is producing more than its switchover voltage the ouput will not change.
In respect of VSRs which many do not seem to understand, they are a cheap way used by the towbar industry to overcome the cost of fitting an original manufacturer bar and changing the engine management config to accommodate it. They also save having to run a decent sized cable from the battery to the socket.
In the old days pre Can-bus and the like the fridge feed to the socket was a thickish cable direct from the battery through a bog standard relay. The relay coil was attached to the alternator warning light output so that when the alternator was providing power the relay would activate and the supply to the fridge would be connected. Stop the engine (or the alternator drive belt failed) and the relay would drop out and the supply be cut off.
The modern cheap solution is to fit a small device that senses the incoming supply voltage on the feed cable and connect said feed cable to the socket via a contact when it decided that the voltage present indicated the alternator is charging. The switching point has a degree of hysteresis - that is the difference between switching on and switching off - so once correctly set up it matters not if there is voltage drop on the feed cable caused by the high current drawn by the fridge, the unit will stay in the on state. From the tests that I did on my last car if the unit is set to switch in at around 14V it will drop out at around 12V or a little lower. Most of these devices have a small variable resistor that is externally accessible and will adjust the switching point.
Large numbers of cars, Ford and Hyundai to my knowledge but there are others, use "smart" alternators to save fuel by reducing engine load - they ONLY give 14.4v if the car battery needs recharging and then stop charging so system voltage is reduced to the 12.5 battery voltage.
This can cause issues with conventional trailer wiring relays, including Smartcom which aren't smart enough to work in this environment.
As I posted upthread, a GOOD auto electrician is needed.
This can cause issues with conventional trailer wiring relays, including Smartcom which aren't smart enough to work in this environment.
As I posted upthread, a GOOD auto electrician is needed.
Thanks all for the information, very interesting. I gave up and got a mobile engineer to come and have a look, first thing he changed the relay in the boot, nothing changed. After some tests he tugged at the cable under the car and there was life. He then took the socket off the car and it fell to pieces, completely rusty, this is 12 months old. Then took the plug of the van and that was well on its way out. Externally they both looked ok, New upgraded plug and socket fitted. All now working. He spent just over an hour in the rain under the car tail gate sitting on the floor and charger me £55, the sockets were ticketed at £9.99 each so i was only too pleased to pay him.
I always pack my plugs and sockets with silicon grease, now that's harder to get I use contralube instead, also spray the external pins with silicon oil.
http://www.maplin.co.uk/p/contralube-770-connector-lubricant-8g-sachet-n78dd
And keep the caravan plugs under a A frame cover.
He did the job very cheaply you did well.
http://www.maplin.co.uk/p/contralube-770-connector-lubricant-8g-sachet-n78dd
And keep the caravan plugs under a A frame cover.
He did the job very cheaply you did well.
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