Towing electrics funny business

[harryp]

May be way off beam, but had a problem with the socket on a Mk1 Xant. Member on the Xantia yahoo groups (here too I think) put me on the right trail. Some of the plugs/sockets have a link built in that shorts out a pin if not required, ie no pin in that particular plug. They are prone to stick - open or shut I can't remember - probably open due to the mechanics. Try a good dose of penetrating oil and contact cleaner. Worth a try.

[Ben82]

Hi Harry, thanks, I have both in the garage so no harm in trying.

[RichardW]

You're reading too much into, Ben! There's nothing clever about it - if the circuit is on it should ready 13-14V, if off, zero (except indicators of course....!). There should be no -ve voltages. What's the resistance between pin 3 and earth on the car? It should be zero.

[Ben82]

You're reading too much into, Ben! There's nothing clever about it - if the circuit is on it should ready 13-14V, if off, zero (except indicators of course....!). There should be no -ve voltages. What's the resistance between pin 3 and earth on the car? It should be zero.

Hi Richard, I will check tomorrow and let you know.

What do you mean "except indicators of course"? Should these have a voltage when off? If so what voltage should they have. as those are getting 0.02V on the C5 when not indicating, but on the i20 it's getting
~3.8V

[wurlycorner]

Is there such a tool for testing the towbar socket,? Eg something with a bunch of w5w bulbs in that simulates the whole setup to ensure it's working? Seems like it's something really simple to have available.

Yep, they're readily available.

One example on ebay here

[Ben82]

Is there such a tool for testing the towbar socket,? Eg something with a bunch of w5w bulbs in that simulates the whole setup to ensure it's working? Seems like it's something really simple to have available.

Yep, they're readily available.

One example on ebay here

Yeah I saw those in the end, but no good to get here by midweek. Found an equivalent over here but they wanted something like £75 for it!!

[RichardW]

What do you mean "except indicators of course"?

To quote the old joke about checking indicators working "Now it's working, now it's not, now it's working, now it's not...."! So voltage should be alternately 0V and 13-14V when indicator is on. Should still be zero all the time when off.

[Ben82]

What do you mean "except indicators of course"?

To quote the old joke about checking indicators working "Now it's working, now it's not, now it's working, now it's not...."! So voltage should be alternately 0V and 13-14V when indicator is on. Should still be zero all the time when off.

ah of course ok thanks!

I have checked resistance: basically from pin 3 to the nearest earth point I could find (door bolts), it is 00.6 ( http://puu.sh/jw117/abbeca8d23.jpg" onclick="window.open(this.href);return false; ) the same door bolts to the negative terminal on the battery is 00.4.

[Ben82]

Just been looking into this again, and decided to take a different approach.

Did continuity tests between the earth pin and the other pins with the car off etc. And I think it's screwed: Pins 3,4,5,6 & 7 all have continuity to each other. Not sure how that wouldn't have blown a fuse. So I guess I should replace the socket and wiring and then hopefully it'll all work again.

[Ben82]

I'm hoping this is the issue; so much corrosion
!

Going to put the new socket on and see if we have success!

[Ben82]

Well that was it had to drill out all 3 screws as they had rusted so much that I stripped the heads trying to get them undone. Luckily for each of them I could find a way to secure the nut at the back so the drill didn't just end up spinning the screw.

Had to use my wire cutters to get the wires out as all the terminal screws had also rusted. Completely so no way of getting them undone.

But stripped new ends and got all the cables back in. (Which was a bit of a stretch as the new terminals had the screws on the back whereas the old had them on the side).
Checked for continuity again to make sure it wasn't in the cables somewhere which it wasn't.

And the final test had been with hiring a trailer again as we needed to collect our daughters new bed. Which wouldn't have fitted in the boot.
And the end result was it all working fine.
The rubber backing of the socket was split so I guess that was leaking in water corroding all the terminals causing the short. Doesn't look like it's solved my issue of the rear fog light not working though!

Thanks all for your suggestions on tracking this issue down