Tow electrics - Grey Socket

Hi

I have a 2000 discovery with twin electrics. Towing lights are fine but the grey socket has no power having checked with a multimeter. Looks like its factory fitted as the cable heads up inside the car behind the drivers back wheel arch. Any idea where the fuses might be or where the power is drawn?

No joy with Haynes on that side

Cheers

Paul

Theres more than likely nothing there....have you looked inside the O/S/R light access panel in the boot?The factory fit,on 300s at least,was a Rists round multi-plug for the tow lighting and a (purple?) battery live,left hanging in space for the 12N (the black one) to be wired to.I wasnt aware that there was a factory fit for the grey,12S (supplementary) socket to attach to.I think dealers would have fitted it to request when supplying vehicle.In which case the fuses could be anywhere.The general rule is to have fuses as close to the battery as possible....do you have any extra,fused,cables coming off the battery?Or extra fuse boxes cable tied next to the main one?

But....I know next to nothing about D2s,sorry!Trying,though!Do you have any means of electrical testing,multimeter?12v tester probe?Light bulb on a couple of wires?Cos you are probably going to need them!

this should help....

http://www.landyzone.co.uk/lz/f8/towbar-electrics-caravan-54784-2.html

Thanks mate

Will check if the grey cable goes into this box where the off side rear light is. First port of call...have a multimeter so should be able to check power in there.

Thanks for the link to...have a pre 99 van so will recheck the wires.

For sure there is no power at the plug at the moment so its either not connected or there is a fuse gone..

Cheers

Paul

If you look on ebay you will see some D2 tow electric kits,just for the black 12N,but it will give you some idea what you are looking at!Let us know how you get on !

Will...as i say the grey plug was already on the car i just put a new plug on. The cable heads up in the same direction as the black one so would seem to be factory fitted....will report back.

Might be a while as removing ace, and have a cracked coolant bottom drain plug housing

Added to the list

So took the passenger side light out and looked down to find a black box with no cables coming out.....took the drivers side out and its got chocky blocks everywhere!!

Think will get it checked over by indespension

Hi there,

If you look under the bonnet at the main fuse box while standing at the driver's side there should be 2 15amp fused relays and a bright yellow voltage sensing relay at the left hand end of the fuse box towards the bulkhead.

These relays are outside the main fuse box so they are visible without removing the fuse box lid. The 2 15amp fused relays should have blue blade type fuses pushed into the top of them and these supply the 12v fridge feed and 12v battery charge feed to the rear grey 12S socket. The big voltage sensing relay only passes current to these two relays when the main car battery is fully charged up again after starting.

You will not get any voltage reading at the rear socket after starting so best to check when you finish a journey before switching the engine off. Someone may have just removed the fuses if they had a problem.

Hope this helps.

Is that a standard factory fit on the D2? If so it could be a useful thing to grab off a scrap vehicle for fitting to D1 or whatever............

borntobemild said:

Hi there,

If you look under the bonnet at the main fuse box while standing at the driver's side there should be 2 15amp fused relays and a bright yellow voltage sensing relay at the left hand end of the fuse box towards the bulkhead.

These relays are outside the main fuse box so they are visible without removing the fuse box lid. The 2 15amp fused relays should have blue blade type fuses pushed into the top of them and these supply the 12v fridge feed and 12v battery charge feed to the rear grey 12S socket. The big voltage sensing relay only passes current to these two relays when the main car battery is fully charged up again after starting.

You will not get any voltage reading at the rear socket after starting so best to check when you finish a journey before switching the engine off. Someone may have just removed the fuses if they had a problem.

Hope this helps.

Click to expand...

Realy i thought the split charge relay was triggered when the alternator started charging (when the battery light goes out), so you get alternator voltage at the socket only when the engine is running to charge the battery in caravan and keep fridge working but disconnects caravan battery from vehicle so that it's not used when starting vehicle, please correct me if im wrong but i don't think i am .

Depends on the type of relay,I dont know what type this is on the D2 which is why I asked if its a factory fit.Often split charge relays are triggered from the charge indicator light wire from the alternator but there are a lot of relays been marketed as voltage sensing devices that claim to only trigger when a peak voltage in the primary battery is reached.This is a subject that gives me a lot of sleepless nights,trying to work out what is best and what is actually true amongst the claims of aftermarket split charge relay sellers.

Me,I trigger a 40a relay off the charge light wire to its own little fusebox and then trigger the larger splitter relay from that.But if there are devices fitted as standard to D2s out there in scrap yards just waiting for me....hell,it'd be plain rude not to try them out!

This is from the Discovery 2 catalogue

Three “S” type electrics kits are available. Two types
provide caravan battery charging and interior equipment
power.
The split charge system protects the vehicle battery from
accidental drainage.
“S” type socket
with split charge system, pre 99MY STC50179
The kit without the split charge should only be used with
caravans built after 1999 when the split charge function
was incorporated into the caravan systems.
“S” type socket kit
for 99MY caravans onwards STC50389
The third kit does not provide fridge feed or battery
charging.
“S” type socket kit
(no fridge feed or battery charging) STC50180

These kits have plugs which fit sockets mounted underneath the D2 fuse box and therefore incorporate other fuse paths than the 2 in the relays visible. If you were to try to fit one to D1 you'd have a job figuring out the other original circuitry that they connect to I reckon.

As far as I can tell the voltage sensing relay compares alternator voltage against battery voltage but thats beyond me. Don't forget these vehicles are cleverer than a lot of us mere mortals.

thanks for this its good stuff.

I did check it after starting the engine but yeah not running for long.

Will check the relays.

I have a pre 99 caravan so if i do sort it out.....whats my wire need to be inside the grey socket?

Will post back tommorow.

Cheers

Paul

Thanks Mildy,good info.Dont worry,I wasnt expecting plug'n'play into the D1.I do my own wiring for aux stuff,heavier than original spec.....just wanted the cool relays,thats all !

Ok no relays under the bonnet so guessing its a after market job. Shonky wiring would indicate the same.....:doh:

Ok behind the drivers side tail light i have loads of wires added and a little box with PCT ON IT.

The code is 17469-PCT-S1

Is this the relay for the grey?

Stick that code into google....add "towbar" or similar if no result,see if its a Witter or Towsure or summat.Other than that,work out what the pins on the socket are for and check continuity 'tween relevent pins and box contacts.

Interferance relay...PCT is a towbar company.

My Grey socket has 3 live feeds, 1 permanent, fed from the 'trailer light' fuse on the engine bay fuse box, then the two voltage sensitive switched lives for the fridge and battery charging. Two earths, one for fridge, and one for the rest, a spare, and a feed for the reversing light.

I have the factory set up, with 2 grey and one yellow relay as described. All spliced into the car loom behind the drivers side rear light cluster.

MW

This is a great place for all caravan and similar info,good forum....

The UK Camp Site for Tent and Caravan Campers in the UK

and especially

Towcars and Towing Advice (Camping and Caravanning) Forums UKCampsite.co.uk Message Board

and....

Repairs, Servicing and Maintenance (Camping and Caravanning) Forums UKCampsite.co.uk Message Board

which is a life saver for caravan owners

This might help too...

http://www.yoc4x4.co.uk/pdf/Ystradgynlais-Overland-Club-Ltd_Towbar-Wiring.pdf

or this....

Caravanning Links