Weird Electrical Gremlin, Pug405 Est

[Pug_XUD_KeenAmateur]

Now this is strange...

For a while now, when I put it in reverse, the warning light on the rear fog switch comes on dimly. Didn't think much of it, but today it took a further turn.

Weather's turned wet, so I needed the Heated Rear Window: I put it on and nothing, even though the light (also on the switch itself) illuminates as it should. BUT..... when I put the HRW on the radio signal dies !

What all of the aforementioned have in common is they all live in the middle of the dash, above the radio & thereabouts*. My first thought is an earth, but where do I start, do I have the trims off and do the nearest ones I know (close to the footwells just ahead of the front doors), and can I tell from any reading I might or might not get on my multimeter, on what setting; if that earth's good?

....and the radio thing with it losing signal, that's just weird !

A couple of notes...
I've not changed the stereo (but I am about to, just ordered one this morning)**
The rear window, just the glass, was replaced a few months ago but the HRW has been fine the 2 or 3 times its been used since and the first thing I did was check the connectors to the glass
The reversing lights and rear fogs work just fine

*the radio's directly ahead of the gearstick on the 405, with the Hazard, Rear Fogs and HRW switches grouped together just above it to its right, ie, immediately left of the s' wheel
**Alba ICS 105, 20 squid new, usual auction site; and it doesn't look like its been designed by a 10year old who's got a blackpool illuminations fetish; result.... hopefully.

Any thoughts welcomed as ever, thanks


NB: what's also weird is that the old girl's definitely more spritely since I changed the cam belt, I reckon at least 20% so; but not complaining. Slight alteration to timing maybe, is there a timing adjustment on the Rotodiesel?

[darbuck]

i think your right about the bad earth but im no good with electrics unless its blatantly obvious, an auto sparks might be your best bet have a look the switch maybe faulty for the rear demister and causing a spike and shorting out other systems or a oose wire failing that id bring to an autosparks because otherwise you risk spiking the bsi which could kill it.maybe someone else will reply best of luck either way.

[spider]

Check the obvious ones first.

Start at the battery. Take the negative lead off (the terminal completely)

Examine the other ends of it. There will be a lead from the negative terminal of the battery to the major mechanical lump, in 99% of cases you'll find this is a lead on the top of the gearbox. This can corrode, examine it carefully.

There's also the negative lead to the bodyshell too. Although things like lights may have individual earthing points, the main negative cable will have a connection to the shell too, examine this as well.

The neg lead itself may just be a dual one like a Y cable, battery one end, and each 'end' of the Y one to bodyshell and one to gearbox.

[Pug_XUD_KeenAmateur]

thanks as ever Spyder, you're a star!

and likewise Darbuck. I'lll have to take my chances with the 'lectrics coz the budget doesn't go anywhere near paying for labour.... and likely my old girl's too old to have a BSI (1996 and one of the last of 'em); I'm not actually sure what one is but me thinks its computer ish.

The main earth is defo to the top of the 'box, can picture it in me head, ring terminal on a big bolt, 13mm I think.

Got big plans for Fri & Sat: this, NS Link rod, new Stereo, and also removing the AC compressor & changing the aux belt assembly over to the non-AC set up using the smaller cast iron mount. Might be playing 'lets see how high I can get this in the air' to get lots of purchase on the Stilsons on the Link Rod; got a good bit of play in the current one. Fingers crossed it comes undone... but if it dont its subframe out & a complete replacement rack in

[spider]

Most welcome.

I can't remember changing the links on these actually, I could be wrong. They do tend to last quite a while compared to say more modern designs with plastic or metal 'drop links' (which rarely come undone)

[white exec]

Bad earth at the back end, on to the tailgate or similar. All the rear lights and HRW should be grounded there, and this just isn't happening properly. So, instead of reverse lights working as they should, they take an poor 'earthy' path back via anything and everything else available, and operate it dimly.

If you can't find the 'missing' rear end earth, just run an additional new cable between a rear light cluster Ground connection and main bodywork (eg boot inside, NOT the opening tailgate/bootlid).

Quite a common PSA fault.

[Pug_XUD_KeenAmateur]

thanks Exec, think I'll be doing that too, with the additional earth... and maybe one between the tailgate itself and the shell for good measure, somewhere around the hinge (the Rev lights and Rear Fogs are both in the tailgate itself, rather than the shell).

NB: is it me or has recent car design gone mad, partic with regard to positioning of external Indicators... and similarly the overseeing official-dom who gives type approval to them.
An indicator's place is at the corner. I especially have in mind those cars where the indicators are positioned on the INSIDE of the headlamp unit, near the Grille, but also the (new) Fiat 500 with a miniscule indicator in the rear cluster and some 90's Rover saloons with the indicator on the inside of the tail cluster

[white exec]

No, I think you're right. Indicators should be as near the corners as possible.

I remember many pre-WW2 cars having all their rear lights immediately either side of the rear registration plate (which they also illuminated). At night, these almost invariably black cars looked about 20" wide!

[Oldpug]

As its an estate I would also check all the wires from the tailgate to the roof.Peel back the gaiter by the hinges and have a tug at each wire.
I`ve known quite a few to have broken wires caused by years of opening and closing the tailgate.

[darbuck]

No bother as for the tie rods if they're any thing like the c5 i bought a pipe wrench which had no socket that would catch so bought one of the other type made of their finest chocolate persisted with it once you can get it cracked open its fine but as there a nice and smooth spherical shape which make them a pig to get purchase on and hence difficult to remove but as i say once you crack the thread they fly off.

[Pug_XUD_KeenAmateur]

Thanks everso for all the replies guys, I've only just seen the latest three, that 'notify me when a response is posted' thingy must be switched off again; so s'cuse my not having acknowledged those previously.

Link to some pix with explanatory text, relating to this and other posts.
https://www.facebook.com/media/set/?set ... 6f3814dc2f

Also, while I'm at it... re 405 headlight upgrade (mine are the singles which are known for the silvering degrading much more so than the twins). It CAN be done
BUT..... even though I have the necessary wiring plug behind the 'Blank' for the twin headlight raise/lower switch, which I have available in my spares; there (surprisingly) is no suitable wiring to power the raise/lower facility at the headlight end. The 'Twins' do however have a recessed Hex to perform this function manually / set them at '0'.

[Pug_XUD_KeenAmateur]

oh & a ps, especially for White Exec, I fully agree with you bout running an earth lead to the bodyshell, rather than just the tailgate, but it looks at the mo like its sorted without actually needing to. However, if I'm proven incorrect, that's next.

[Pug_XUD_KeenAmateur]

just to put the 'tin lid' on this one, and 'close' it, after a rainy day yesterday, much head scratching and plenty of faffing about with a multi-meter, the fault is found at last.

With a temporary earth in place (a very in-elegant but effective wire to a boot latch bolt) and the HRW on, three small round clear patches in the fog on the window showed up at least 3 broken elements.

Currently they're equally in-elegantly highlighted with some bright masking tape X's (on the outside where they'll not rip off the element when removed), but if you look really closely you can see the breakages as grey or brown areas in the element.

I've some 'Silver' repair on order, which at £7 is half the price of the kits whereby you also get a Cocktail stick and a little brush (whoopee-doo); and I'm going to 'enjoy' sorting it out as its clearly one of those nasty fiddly jobs I loathe; but that's clearly the fault.

Thanks again everyone and if your HRW doesn't work either, but you've got current across it, take this as advice and hopefully sort yours.

[spider]

The silver repair paint I've never had a great deal of luck with but I've only tried it probably twice in my life.

I'd recommend careful use of tape (or someone to hold something like a plastic rule) when you apply it.

The problem with tape is there's a slight risk of pulling the "new line" off if you're not careful.

[Pug_XUD_KeenAmateur]

I'm a bit doubtful meself about it too Spider, it'd be more likely to work if I was to remove the tailgate and lay it flat but I ain't that desperate!

Weird that it worked just once or twice and then popped several elements, me thinks maybe there was some crud on it or summat (having replaced the glass recently after that post jumped out & hit me).

A further 'when I can be bothered' task is having a go at getting sealed glass out, practicing first on anything with the glass sealed in at my local scrappy (eg. any 3 door hatch) with a thought to maybe being able to remove one of my rear fixed lights (side of the boot) to sort a slight bit of rust that's just appeared and ain't gonna get better on its own. Understand the method is Cheese Wire. Ever had any luck?