Backing out

MikeT · Unread post by **MikeT** » 01 Apr 2009, 13:07

Has anyone heard that phrase before in relation to French cars and electric sockets (are they made by mirelli or similar name)? I've been told by an experienced mech/tech that over time, these relay and fuse sockets get a touch "baggy", which creates extra resistance which in turn heats them up more and allows the connectors to "back out" of their holes cauing poor connections.

As he mentioned the infamous ignition/heater and headlight faults, it seems he knows what he's talking about but I've never seen mention of it before on here.

citronut · Unread post by **citronut** » 01 Apr 2009, 13:23

i belive the heater fan/ignition switch failiure is down to the driver switching the ignition on and off whilst other heavy curent draw electics are switched on, ie heater fan head lamps, it is my policy to switch every thing off before turnning off the ignition, as it saves the contacts in the ignition switch burnning out prematurly

regards malcolm

MikeT · Unread post by **MikeT** » 01 Apr 2009, 17:21

Hi Malcolm, that's my thoughts too after reading of many such examples on this forum. If the man is correct and some connectors are backing out that will increase the resistance and so it follows that it could well be contributing to the ignition contact burning.

I was just asking to see if anyone has found such a problem as it should have surfaced by now if it was a common occurence. I mean, it is well-known that a Xantia's connectors are not the best fitting - i.e. air-bag, coolant sensor, injector lift sensor, blower motor etc

Stempy · Unread post by **Stempy** » 02 Apr 2009, 08:06

I've had some problems on mine with the spade contacts on relays and fuses going high resistance. I replaced all the fuses and two relays in the end, but the main culprits appear to be the ones in the under bonnet fuse box, especially in damp conditions. Sprayed all the sockets with contact cleaner too. Not had any further electrical issues since doing this.

BTW the way I discovered this was by actually measuring a voltage drop across some of the fuses.

Unread post by **Old-Guy** » 03 Apr 2009, 12:06

I can't speak with direct experience of this problem on Xantias, but...

'Backing out' was a well-known problem with electronic devices in sockets (as opposed to soldered onto a pcb).
Vibration and temperature-cycling seem to be major factors; devices (such as relays) can work their way out of sockets against gravity. I believe it's important to not interfere with the way relay and fuse units were originally mounted as this could cause vibration at a problem frequency.

Corrosion of base metal (brass, copper, or zinc plated steel

) contacts is inevitable where traces of salt are present. Salty moisture creeps between the contact surfaces by capillary action, the resulting corrosion forces the contact surfaces apart. The corrosion creeps further and further causing sparking that burns and pits the metal. The only cure is to clean contacts thoroughly of corrosion, oxidisation (burning) and pitting (as far as possible) and then treat the smooth bright surfaces with something like WD40. Beware that WD40 will not provide a good contact where one doesn't exist nor will it remove salt or corrosion - it's only ability is to protect clean contacts by repelling water (contaminated with corrosive chemicals like salt).

Prevention is better than cure - make sure protective covers etc. seal properly to keep out salt spray. BTW - never pressure wash under the bonnet, wash salt off with a gentle spray from a hose.

Unread post by **myglaren** » 03 Apr 2009, 18:19

How aboute a bit of Vaseline?

I have found it to work wonders - and not where you are thinking you naughty boys!

I smear a little on the pins of halogen bulbs and find them much easier to change when they blow but also they last much longer.

Also on standard bayonet bulbs and find the same, I know most sockets aren't a problem but some can be and a bit of Vaseline prvents that.

A lot of other stuff gets a dab of Vaseline on it too, like chicken soup for the DIY person (put it on woodscrews, the go in so much easier and come out easy too, when you want them to.
Relay pins being a prime example.

I have never found it to diminish contact although I did expect it to and it does seem to help to keep corrosion away.

[/Vaseline commercial]

citronut · Unread post by **citronut** » 03 Apr 2009, 19:50

seems like a nice boy ooooooh la la

isnt it good for chap to

TEA HE

regards malcolm