Trailer board electrics

grldtnr

Well-Known Member
Not sure this the best place, I have an LED trailer board, worked fine when first had it, but since then I changed cars,still a Skoda but a more modern model.
The problem is it's not working properly now, the lamps light up in the wrong fashion, put the turn indicators on the brake & rear lights flash in sequence to the turn indicators, the brake lights work, but then the indicators flash as well, the only function to work properly are the rear tail lights , a conundrum indeed!
I suspect a short somewhere, there is a bare patch of wire, which I temporary taped up , but still happens, being LED, I can't see how to strip the wiring out to check it.
I use it for trailer mounted bike rack ,& when trailing the boat.
any wise scrotes here?
 

CXRAndy

Guru
Location
Lincs
A quick test is find another vehicle to test your board on. If its good, your car has a problem. Alternatively get a pinout for your plug and check everything is correctly wired up.
 

T.M.H.N.E.T

Disc brakes - Stopping things since 1902
Location
Northern Ireland
Grab yourself a universal wiring diagram off the internets and a multimeter. Turn each light on in turn and probe with the meter, indicators/hazards should give an intermittent reading, tail and brakes steady etc.

It's entirely possible the socket is wired wrongly, the relay (who fitted the towbar and electrics, and did they use a universal relay?) is wired incorrectly or not configured for led lightboards (have to add a module)
 
OP
OP
grldtnr

grldtnr

Well-Known Member
Grab yourself a universal wiring diagram off the internets and a multimeter. Turn each light on in turn and probe with the meter, indicators/hazards should give an intermittent reading, tail and brakes steady etc.

It's entirely possible the socket is wired wrongly, the relay (who fitted the towbar and electrics, and did they use a universal relay?) is wired incorrectly or not configured for led lightboards (have to add a module)
The LED board worked on the previous car, but yhat didn't have fancy canbus tech on it.
I have another board , plus a box trailer ,lights work ok on them but they are incandescent bulbs.
I suspect that something is amiss with the car electrics, it doesn't want to play with the LED arrays, it was professionaly fitted bar & electrics, and had onboard electrics enabled, such as stability package, so should work.
Something is definitely amiss?
 
OP
OP
grldtnr

grldtnr

Well-Known Member
Grab yourself a universal wiring diagram off the internets and a multimeter. Turn each light on in turn and probe with the meter, indicators/hazards should give an intermittent reading, tail and brakes steady etc.

It's entirely possible the socket is wired wrongly, the relay (who fitted the towbar and electrics, and did they use a universal relay?) is wired incorrectly or not configured for led lightboards (have to add a module)
Lights are wired correctly, I swapped out the plastic plugs for metal ones, always worth the palaver, I ve wired a few up in my time, so am aware of what goes where, I 'tinned' the wires before hand.
Will just have to get the wiring out of the board, could be awkward, perhaps something had nibbled it but no evidence at present.
 
Having fitted tow bars and electrics to 4 of my own cars, the first thing I would do is see if the cars 12n socket is wired up correctly to its input cable. 2 simple ways of doing this, firstly test the car with a different trailer / caravan/ test device. Secondly use a multi meter / 12v bulb in contact with the various pins on the cars socket to see if it’s compliant with below. The fact you said that the board worked on a previous car implies it’s the new car that’s at fault.
620517
 
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grldtnr

grldtnr

Well-Known Member
Having fitted tow bars and electrics to 4 of my own cars, the first thing I would do is see if the cars 12n socket is wired up correctly to its input cable. 2 simple ways of doing this, firstly test the car with a different trailer / caravan/ test device. Secondly use a multi meter / 12v bulb in contact with the various pins on the cars socket to see if it’s compliant with below. The fact you said that the board worked on a previous car implies it’s the new car that’s at fault.
View attachment 620517
The wiring loom on the LED board only had 5 wires, no fog or LH side light, presumably there is a flying jump connection for both tail lights inside, there isn't A Fog light on this board either,I can only think I have the earth wired wrong, as the tail lights are the only ones that operate correctly.
I carefully noted which wires gob where before I rewired the plug , and wrote down on the back of the light board the wire diagramme.
I am guessing I will have to withdraw the wiring harness via the lamp mounting holes, but undoing the nuts that hold it on is awkward, I haven't a socket or nut spinner deep enough to do it.
 

CXRAndy

Guru
Location
Lincs
Its very easy to get wiring back to front confusing the socket pins to plug pins. Some connectors are poorly marked so make it doubly difficult.
 
The wiring loom on the LED board only had 5 wires, no fog or LH side light, presumably there is a flying jump connection for both tail lights inside, there isn't A Fog light on this board either,I can only think I have the earth wired wrong, as the tail lights are the only ones that operate correctly.
I carefully noted which wires gob where before I rewired the plug , and wrote down on the back of the light board the wire diagramme.
I am guessing I will have to withdraw the wiring harness via the lamp mounting holes, but undoing the nuts that hold it on is awkward, I haven't a socket or nut spinner deep enough to do it.
I understand what your saying but my original advice still stands.

https://www.ebay.co.uk/itm/7-Pin-Tr...2349624.m46890.l49286&mkrid=710-127635-2958-0
 

DRM

Guru
Location
West Yorks
As above, probably the car, check what's happening at the socket, if it's ok I'd remove the light lenses from the trailer board and check continuity from the connector plug to each light, and the earth as per the diagram, if thats ok it could well be the trailer board being LED isn't giving the correct load to the supply.
 
OP
OP
grldtnr

grldtnr

Well-Known Member
As above, probably the car, check what's happening at the socket, if it's ok I'd remove the light lenses from the trailer board and check continuity from the connector plug to each light, and the earth as per the diagram, if thats ok it could well be the trailer board being LED isn't giving the correct load to the supply.
Don't think car is at fault , other trailer boards work with incandescent bulbs, most likely a fault with the LED board, perhaps that tester someone posted will help, but I do know there is a bare wire on it, the insulation had come away, I need to find a socket wrench that's deep enough to undo the LP's to get at the loom.
 

DRM

Guru
Location
West Yorks
Don't think car is at fault , other trailer boards work with incandescent bulbs, most likely a fault with the LED board, perhaps that tester someone posted will help, but I do know there is a bare wire on it, the insulation had come away, I need to find a socket wrench that's deep enough to undo the LP's to get at the loom.
Have you got a multi meter, remove the lenses and check continuity from the plug connector to the live side of each LED, then check you have an earth connection from plug to each LED, note the pin that’s the earth, check that non of the other pins are shorted out to each other, if these are all ok, then the canbus system and light module may not be seeing the correct load from the trailer board, so the canbus system is baffled by the lack of current being drawn, do you know anyone with an older car with a tow bar who will let you plug your trailer board in to see if it’s ok on their car
 
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