Socket on towbar

Post by **27.86** » 04 Nov 2006 09:15 pm

Hello. Please could someone let me know which pin on towbar sockets operates the indicators/hazard lights. Got to move my caravan in a couple of weeks, and the indicators aren't working on the trailer board I just bought for the purpose! Will check the board to make sure the indicators work on that, but think it's the socket that's the problem (indicators didn't work on the caravan when I tried the car with its lights, but quite a few lights don't work on the caravan & haven't got the time right now to fix them!)

Think there's something on here about sockets, but not sure where!!!

Thanks for your help.

Post by **redline** » 05 Nov 2006 12:19 am

this should help

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Post by **27.86** » 06 Nov 2006 10:32 am

Thanks, Mick. What's the best way of checking whether or not the pins are working?

Think it might not be a socket problem after all, if neither indicator works - thought they'd be on the same pin (not sure why I thought that!)

Post by **redline** » 06 Nov 2006 01:10 pm

cheapest /quickest way to check the pins is to get an old bulb holder and bulb with a length of wire on each terminal ,

start car and put on one indicator ,
touch one terminal to earth and hold the other one on the correct pin if your bulb lights the socket pin is ok ,
do the same for the other side,

If this dosent work the fault is between where the original loom has been tapped into for the indicators and the tow bar socket , there should be a relay and either an audible or visual warning system ,
check all the connections,

I have heard if you have a visual warning light and the bulb in that dies it will stop the socket from working but cannot be sure .

may have to replace the relay which sounds likely as neither side is working

If this works but then stops working when connected to the caravan it may be worth poking a small screwdriver carefully down the centre of the pin to slightly open the two halves,

this will help the relevant female part of the socket grip the pin better and should make a better contact (we had this problem with the sidelights on our van ),

hope you get it sorted I have just put my beast to bed for the winter

27 foot of pure roadblock

Post by **27.86** » 17 Nov 2006 08:21 pm

Mick, I had a look at the socket on the car, and there are 7 holes but only 3 of them have pins in - it's the same as on a couple of other cars I've looked on.

What am I missing here?

Thanks,

Andrew

Post by **Andy's-Old-Beast** » 17 Nov 2006 11:19 pm

Hi Andrew.

See your PM for my answer to the location of the indicator relays. I just spotted this thread, didn't realise both were not working.

redline wrote: I have heard if you have a visual warning light and the bulb in that dies it will stop the socket from working but cannot be sure .

may have to replace the relay which sounds likely as neither side is working

The 'visual warning light' theory is true, but I did not install one in this case. I did all the towbar wiring myself, and used a couple of headlight relays out of an old car.

I used two relays, one for each side so I don't know if it will be the relays at fault. As I said in Andrew's PM, you should be able to hear them 'ticking' inside the boot when the indicators or hazard lights are on.

Thinking about it though, I probably used the same power source for both relays. Each relay is a switch, activated by the car's rear indicator lights being live. When the car's indicator bulb is lit, the relay connects the relevant pin on the towbar socket to a live 12v + power supply. It's this power supply which lights up the indicaors on the trailer.

If the relays are ticking but there is no power at either of the indicator pins on the towbar socket, find the relays (as described in my PM). There are 4 wires plugged in to each relay. Two (on each) will be connected to each other and to earth. One will be connected to the wire for the indicator bulb in the back of the car. The forth will be the supply - follow it! I can't for the life of me remember where I took the +ve power from, but I can't think of any live supplies at the back end of the car, so it probably goes to the front end of the car somewhere, possibly through the interior... If you can follow it, check the connection at each end and try to establish a 12v + supply. Good luck!!

27.86 wrote: ...there are 7 holes but only 3 of them have pins in

There are 3 "male" pins (arranged in a diagonal line) which stick out. The other 4 are "female". (I guess technically they aren't really pins!) They look like holes but if you look carefully into each hole you'll see it is lined with a metal sleve. This is the connector. It should mirror the plug on your trailer board, so the males all plug into females and vice-versa.

Hope this helps, and good luck with it all!

Andy.

PS, hi everyone! Hope you're still enjoying the 300s. I try to sneak a look on here every now and then, just to keep up to date..!

Post by **27.86** » 20 Nov 2006 08:05 pm

Thanks for the extra info, Andy.

In case the relays on the car are at fault (you never know...), I've got another 340 with a towbar, so I could use the relays off that if they work. Are they likely to be in roughly the came place (at the back of the car, near the lights)?

Post by **Andy's-Old-Beast** » 21 Nov 2006 02:13 am

To be honest, I did the wiring for the towbar in my old car myself, so I have no idea where you'd find the relays in a car wired by a 'proper' mechanic or towbar fitter. Maybe someone else with a factory towbar is reading this and can give us a clue where the relays are??

Did you try sticking your head in the boot with the hazard lights on yet? I think the chances of both relays failing at the same time are pretty slim.

If you can hear them in the boot, it's a good bet that they're working. It will sound like the normal indicators do when you're in the front of the car (ticking as the bulbs flash on and off) but it will be noticebly louder in the boot, especially with the rear light covers off.

Given that both indicators are not working and I used a seperate relay for each, I think your best chance is to follow the supply wire, as described earlier.

Out of interest, does the interior light in the boot work? I was thinking about it last night and I have half a feeling I may have tapped the supply for the towbar indicators off it. It should have one wire which is live all the time, as it earths the bulb through the boot strut when it's open.

I think the lens for the interior boot light just pops out if you lever it with a scrwedriver. Have a look at the two wires, there might be one of those crappy blue plastic square 'clamps' on one of the wires, with another wire coming out of it. Might be worth checking connections there and maybe the relevant fuse for the interior lights?

Let me know how you get on.

Post by **27.86** » 21 Nov 2006 07:45 pm

Thanks for the extra info, Andy. No, the boot light doesn't work, so I'll have a look at that - maybe sort the boot light & the indicators out at the same time!

Going to be having a poke around tomorrow with a borrowed multi-meter, so will report back with news as & when...

Website · Post by **antiekeradio** » 21 Nov 2006 08:19 pm

that sound like really neat towbar wiring, with supply wire from B+ and relays etc to drive it all...

most V300's with towbars i've seen were dealer-equipped with nothing but a bunch of wires clamped to the original wiring with.... scotch blocks

despite the fact that such wiring is particularly dodgy because of the scotch blocks, the other electrics do not seem to suffer at all... the extra load of the lamps on the trailer does no trouble whatsoever to fuses or blinking frequency.

Post by **27.86** » 23 Nov 2006 09:32 pm

You know, it's funny you should mention that!

All fixed now - took out the very manky looking relays & bunged in a new one, and all fine!

However, I had a poke around both my working car and my 'spare' car (last night, in the dark & rain, outside...

) and the other car just has spurs off the car's wiring for the towbar. All very neat & tidy. However, you have to have an audible buzzer in the UK so I went to Halfords & bought the right thing, as much to rule it out as a problem as anything else. I then dropped & broke it, so took it back & exchanged it for a new one! Hehehehe. Anyway, fiddled around with the wiring & everything now works - for now at least!

Thanks, Andy, for your help. I couldn't have done it without you!!

Post by **Andy's-Old-Beast** » 24 Nov 2006 08:11 am

No worries. Just glad to keep the old beast on the road a bit longer!

I'm suprised it was the relays, but obviously it was them, so that's me told!

Good work in tracing and sorting the problem.

Happy motoring! And lets see some pics of it with those alloy wheels you were on about. If it's those BMW ones you mentioned in another thread, I imagine they'd look quite good!

Andy.