Near side lights electrical issues - Help me please

I've drawn a blank on this one & it's starting to annoy me now as it's stopped me getting the car mot'd & on the road this summer.

Background story: Previous owner replaced fusebox due to water damage with a second hand item, they messed up all the relay positions when swapping it over, car then failed to run, they then lost interest, i bought it.

Thanks to the forum, i've corrected all the relay locations, removed the crappy alarm system, the car primed as it should & now runs - yay! Except i can't for the life of me get  the n/s brake light, side lights to work! It keeps blowing the fuse every time.
So far i've removed interior, traced the loom from box to light all the way down passengers side, checked for any damaged wires - none. I've replaced the entire length of wire for new just to be sure. I've cleaned the lights internally, checked all connections, etc, but it still blows the fuse every time.

All i have left now is the fuse box itself?? It looks second hand, is it possible it has an internal fault somehow? Could previous owner have damaged it by putting connections in the wrong place? It's driving me mad!!

Left or right side, I am assuming the right side.

The Brake Lights and the Side markers are on 2 separate circuits.  

So the fuse number is critical for us.

Now if you mean the rear running light, and sides then look for static ground via the rear.  

Fuse blowing is a Direct short from earth to 12V source.
So it likely isn't a Bulb.  

For sake of argument, what year and model assists us.

Ever wonder what is under that fuse box cover?



Well,


While it is possible that you have a bad box, you may have a issue with the plugs for the sides or the tails, and if they are the near side is the issue at the front or rear.  To disconnect the circuit, I would take all the bulbs out, this eliminates continuity in the circuit via a bulb……  

Turn the lights on and see if the fuse or fuses blow? If they still blow then you have a wire short in the box or wiring to ground.  

To eliminate the issue of loom or box, you can disconnect the loom from the fuse box and try it.  If the Fuse blows then you know it is possibly a relay, box, or if the lamp switch is in the same loom, then it is possibly a bad switch.

Until I know the model I can't look up the schematics to assist you …….

Trust me to leave the car info out!

Thanks for taking the time to reply. The car as an 83 tin top gti.
It's the passenger side front and rear side lights and brake light.
I've tried taking all the bulbs out already, I've replaced the light switch for a new item,  still blows the 10amp fuse as soon as you switch it.
If you do have any diagrams handy it would be much appreciated.

Still blows the fuse with the bulbs out?

So the issue is that you have something screwed up.

The brake lights are a dual filament bulb IIRC that is one half is for Brakes and one half is for tails or markers.
SO it is most likely the Running side of the Brake light.

Easy to tell as the Tail light socket has 2 metal strips separate from the ground.  

I suppose that some one could of wired it backwards, instead of the Markers having full time ground ans switching 12V they could of made a mistake and got the wires crossed for that side…..


I imagine that if you put the brakes on, they work both sides.

Which fuse?

I have back to 84 Cabriolet, and I have the WESTY (USA) versions of the Wiring 77-84.I also have a Bentley
for 77-79 Rabbits/Scirocco, the price on it is 18.95usd….dated 1980, the wiring diagrams are in COLOR and fold out…. AWESOME.

My Brother bought it at a yard sale for 50 cents.

The EURO which is more like the Cabriolet I am a little shallow on.  

You may have a corroded Socket or one that is shorting earth to the power.  

If you take out the fuse and use a meter between ground and 12v on one of the lights I imagine you will have a short (resistance ).  You will have to look at the bulbs sockets in the rear and front to see if they are corroded internally.  I would suspect the side markers over the tail lights.

An DIGITAl Volt Ohm Meter is going to be your friend….

Right I've had another go at this today. Spent another 4 hours on it and still no further forward.

It's fuse no6 that keeps blowing, near side circuit.
Today I've unplugged every single lights on that side, still blows. I've replaced the fuse box for a brand new one as it was showing signs of corrosion, it still blows.
I found out that if I unplug the yellow 'c' plug from the fuse box, the fuse won't blow so I've carefully stripped that section of loom back all the way through from box to headlight connectors but it all looks ok.
I've removed the dash again to see if anything obvious under there, not a lot.  
I've taken a few pictures to show you what I'm dealing with - not fun. It's surprising any thing works.  
I wish someone reproduced these looms.

Headlight switch plug

This shows corrosion on the white black lead.

Just for giggles have you replaced the switch?

A fuse that blows is a Direct Short to ground.
One of your power leads (wires) on that side has a Path to ground.

Now-a-days engineers are wrapping the looms and trying to prevent issues, but over hear manufacturers are using a "Green" wire, that the plastic is very tasty to Rodents….. (soy plastic).  So newer cars while almost better designed, are tasty morsels for Rats, and Mice. So I suspect it is a trade off.

To find the wire you are going to measure for resistance to ground all the power wires from the switch to ground.
So if you undo the yellow connection, one of those wires powers the lights on that side and goes to ground.

A DVOM is going to be your friend, and or a 12V test light.

With a 12V lamp, you could place one side of the light on +12 and then touch each wire on that yellow connector to see where it is lighting the light, and it doesn't have to be very greatly lit to be the issue.  Once you find the wire then you can trace it to the breaking point, or cut it out and run new.  Solder less or Crimp connectors are good, but solder and heat shrink are better and usually last a life time.

Measure each wire for 0 Ohms to ground, you will find one that is pretty close.  That is the wire I would suspect.
It could be cut any where from the Fuse box to the tail light.
Usually from my experience it is under the carpet or at a bend where the break and short are.

I too wish there were replacement looms, but there are only the different parts, and you make your own.
I had to do that on a 58 Bug-eye, Granted there weren't a lot of wires but what with Lucas and the 2 Fuses, there were a lot of places that
would produce smoke to protect the fuse.  I learned alot on that car, Carried over to my 67MG, then my Rover.  I learned even more
working on Aircraft Electrical, and then Computers…  Wiring issues while not fun to most, are fun for me I relish in figuring out where the break is.


 

Thanks for reply. I'm so close to giving in and selling up.
I've got a brand new switch and tried that, no difference. I noticed the corrosion on the plug that's why I pictured it but I'm not convinced this is the cause??
I have a digital volt meter but only know basics.
Ive gone through the pins on the yellow plug with all bulbs removed to check for any shorts to ground by doing a continuity test and drew a blank as I couldn't find any. Can you elaborate more on what I need to do?

I have exposed all the passenger side wiring from taillight to fuse box and from box to front lights. I've checked all wiring and it seems to be OK visibly.

I'm at a loss, it's a complete mess around the box as it seems to have loads of parts added over the years. Can you buy the plugs still? Tempting to rip it all out and start from scratch.

Any corrosion is resistive to the circuit.

Start at the Yellow Pin, find where all the wires go and measure resistance to ground on each pin, then check it against the Schematic for your car.  I don't have Euro Diagrams for the 83.

I would Since you have the Fuse box out, you might want to open it up and verify that there isn't any corrosion in it.  Corrosion in it will look Crusty, or chalky in relation to the photo that I posted earlier of the 89 Fuse box out of a Cabby.

I could also be that the circuit is overloaded, that is one side is shunting the voltages and exceeding the current value on the Fuse.  

It could be that they are improperly fused, ie: a 10Amp fuse in a 15 amp circuit.  in the Bentley or Haynes next to the fuse number is usually listed the amperage value of the fuse.

Explanation of Circuitry difference parallel/series
http://volkswagenownersclub.com/vw/showthread.php/78433-Typical-Series-Parallel-Relayed-Circuits

Some Basic electrical information

Electrical/Educational

Educational:

Inside of a fuse box
http://forums.vwvortex…er-Look-inside-a-fuse-box

Definitive Radiator fan operation explained:
http://volkswagenowner…-Fan-operation-explained-

Basic Electrical Tools for most common Repairs/Diagnosis.
http://www.toplessrabb…/viewtopic.php?f=7&t=3211

Improving your grounds 93 digi.
http://forums.vwvortex…nd-the-repair-of-your-car

Improving your cluster grounds.
http://volkswagenowner…er-Connections-and-ground.

Electrical Primer
http://volkswagenowner…php/32254-Electric-Primer


Parasitic Drain Video
http://volkswagenowner…228-Parasitic-Drain-Video

X Circuit, and Ignition switch explained.
The "X" Circuit from the Ignition Switch. | VW Vortex - Volkswagen Forum

Ok thanks.

The fuse box is brand new, I changed it to rule that out.

Each side of lights is running a 10amp fuse which I'm sure is ok as the drivers side doesn't blow with the same rating.

I'll read up and try get back on it soon. Thanks for the guidance so far.

Going to have another go with a fresh head. Have re read your replies and I think I'll start with this:

With a 12V lamp, you could place one side of the light on +12 and then touch each wire on that yellow connector to see where it is lighting the light, and it doesn't have to be very greatly lit to be the issue.  Once you find the wire then you can trace it to the breaking point, or cut it out and run new.  Solder less or Crimp connectors are good, but solder and heat shrink are better and usually last a life time.

fingers crossed
 

check out the CE1 section of this thread:
http://www.clubgti.com/showthread.php?219775

with the C plug disconnected and sidelights on, does the rear sidelight come on?

for the left side the wire you need to chase is C/4, grey/black.

I dont like the look of the loom near the fusebox, I see random cut green wires, a random black wire with inline fuse tapped in. lots of black loom tape covering probable bodgery.

What I would suggest is you remove all the black insulation tape, and all of the extra wire bodgery that has been tapped in. cut back to factory wiring harness, then work back to source to see whats been cut into. refer to my fusebox faq guide to repair said bodgery, then see how you go.

see my signature link also, jetta89.pdf should help a fair bit as its the same fusebox, it is for us spec jetta mind but it should be close enough for your needs. I do have the 83 ce1 mk1 diagrams scanned in from the haynes but haven't got round to converting them  to a pdf yet so feel free to email/pm me and I'll send you those too if you need them

Update:

Right i think I've got somewhere with this - fingers crossed all seems to be ok at the moment.

It seems i had two faults,

Someone has fitted i boot popper as the tailgate has been smoothed in the past. Turns out it had been wired via the OE rear wiper motor loom but had left exposed connections within the boot which occasionally shorted to the body!

Other fault was very corroded number plate bulb holders with a dodgy supply which might have been shorting to body.

All seems to be good now (for now!) so thank you to all who helped me. I'm now going to clean the loom up and re-tape it, sorting any other bodges i may come across.