GT2 with various electrical headaches

[MacColl]

I have had a intermittent rev counter, checked earth straps, coil wires now nice and clean and not liking the look of a lot of the wiring on the car so I decided to remove the old alarm and what a nightmare it was spliced in all over the shot especially round the ignition which involved me having to cut, solder and where possible shrink rap..


I also found this wiring on the rad fan and don't know how to wire it? see the second pick I left out the red and white wire from the rad which I believe is an option for a slower speed. Hope the fan kicks in?



Now I have removed the alarm the interior light isn't working and I have cut the wire but not the original wiring as you see in the pick there has been overheating/melting, don't know how to sort this, don't like the way the new wire (black) has been routed and starting to tear the headliner..


Also why would the wire seen here be cut and what seems like earthed to the body (see green ball) should this brown wire be soldered back to where it is cut at the green tape?



I've also got these wires under the dash that I have shrink rapped on the ends, don't know what they are? one I might have cut that goes to the centre console..



I also had the rev counter/speedo out and don't see any bad connections or breaks? I also find the speedo works but is very twitchy?
The car has had electric windows and central locking both not in the factory and they still work electrically (windows stick but more mechanical)

Whats this stuff for, the blue box? is it for the windows or central locking? also does anything here look dodgy?



I can match wires that look stock and solder/shrink rap but now I am a bit lost with this How will I sort the inner light without damaging the headlining? I'm thinking there is some sort of earth issue or total incompetence issue

[MacColl]

Made some discoveries, the black wire to the centre console I believe was to the small led light for the alarm so that is accounted for.

The blue and black wires under the ignition, one is an earth (see screwed to body) probably from the alarm and the other is for the interior light switch that the door activates. It seems to have been replaced with a black wire up the windscreen seal. So if I can get new wires up the pillars I can re-wire the light properly.


The speedometer seems to have improved now that I have messed with the cable at the back but is still very jerky at low speeds.
The rev counter remains dead Maybe just needs replaced so I'll look at taking the clocks apart and swapping the rev counter and damaged clock from the old Scirocco clocks I have.

So questions still remain..

1. Why would someone earth the brown/black wire from the Pierburg to the body at the green ball?

2. Is it correct to wire the black/red wire leaving out the third white/red wire for a single speed rad?

3. Is there any other reason why the rev counter wouldn't work like wiring/earth or simply broken? it was working intermittently

4. I take it I should be able to pull good wires through the pillars of the windscreen with the old?

Any suggestions would be appreciated

[DT1]

Do you have a Haynes manual to check the wiring?

According to that there are 4 wires connected to the switch:

3 earths
brown/white = left door switch earth
black = right door switch earth (although on mine I think they used another brown/white)
brown = permanent earth

1 power
red = power (you have checked the bulb and the fuse?)

Just check the continuity between the interior light switch and the door earths, check the power circuit, it should be permanent live and if it is check the permanent earth using the light switch.

There is nothing suspicious about the red wire being melted, the lamp gets very hot and if the wire wasn't routed properly it may have come too close to the bulb and melted. I even had the light fitting itself crack once due to the heat, that's why it is good to swap it with an LED bulb.

In the same vein, the 'new' black wire might just be replacing more damaged wiring.

It's hard to tell what is connect with that lump of red tap in the way.

[MacColl]

Colin much appreciated,

I was looking at the wiring in the Haynes, never really had a clue about these diagrams but I do see those three earths/power wires on p292

I've never done anything like checking continuity before but I suppose this would be time to have a go. I'll maybe get a tester from my local Toolstation.

I have definitely cut a wire, probably the 'new' black one that seems to be joining the red wire at the light. It had an led style light that I didn't like so I had put in a standard bulb. Only one of the door switches made the light work until I had removed the alarm the other day. I'm a bit dyslexic so it has taken me a while to get my head round this and the other bits of wiring like the stereo. The amount of wires for the electric windows that passes the bottom of the pillar made things a bit intimidating. I've now got all the plastic panels out from under the dash so can hopefully get this figured out. Also very close to fitting Weber Carb to simplify things. Nothing worse than not knowing what a problem is

Was thinking of posting something up about a Scottish get together, what do you think?

Thanks again

[ianaudia4]

You can pick up an inexpensive multimeter from the likes of Maplin, maybe for a tenner and it does more than test continuity.
I hope you get your Scottish get together, collective minds etc.

[MacColl]

Good call Ian

I'll get a multi meter, as you say will have more uses.

I was actually thinking of a Scottish meet as much for social reasons but any input would be good. The car is bugging my life right now with a number of issues.

[MacColl]

Well I had bought the Draper Multimeter on the left and found it was completely dead with battery fitted so rather annoyed I had look about my Grandfathers bits and found these two..


He passed away over 15 years ago and what a legend he was, an engineer like his father who worked on Spitfires during the War and the sort guy that who taught himself to re-wire the house. What I am impressed by is the fact that he had the foresight to remove the batteries so they are in working order The middle one has a buzzer to test continuity

[MacColl]

Found the remnants of the red live wire for the interior light near the fuse box..


The three earths main/door switched all have good continuity so what I'll need to do is track where the live comes from the fuse box and hopefully replace it. Think I can drag the wire through the A-pillar with a thin piece of string.

The interior light shares the same fuse with the Cigarette lighter, radio, dash clocks, interior lights and central locking? I see the fuse is a 10A not a 15A that I believe it should be?
Would any of these or simply the heat from the interior bulb cause the melted insulation/therefore shorting?

So might get this sorted soon then get an understanding/address the other bits of wiring with some better heat shrink tube. Also been reading up on tricks to soldering

[Nate]

i'd put money on that being caused by a chaffed wire somewhere. not completely shorting out, but drawing enuf current to get the wire way too warm. either that, or something had been earthing back thru it due to a dodgy earth somewhere else

[MacColl]

Thanks for suggestions Nate, I'm hoping that it was simply the hot bulb causing the problem, it has had the electric windows installed and central locking post factory. There is evidence of other melting on another connection maybe the old alarm.

I found where the wire goes on the fuse box sharing the rear boot interior light which works. So I should be able to replace the wire by soldering here. I can't seem to pull through the old wire and plastic covering so might put the new wire up the drivers side A-pillar. I'm concerned though because the two earths that do have continuity beside the melted wire might cause problems.



I know it's only an interior light but I just want things back to standard and safe

[MacColl]

There is light

With force and a piece of string attached I pulled the two earths through the A-Pillar and found..


Even with continuity they could have posed problems with shorting so I made up two new ones added a fresh live wire all nicely soldered and heat shrunk pulled back through and re-fitted everything. No burning smells and fully functioning with door switches




Not intimidated by wiring any more, got the stereo to sort next. The rad fan hasn't been kicking in when in town traffic so will put the wires back the way they were. The fan has clearly been changed at some point.