Wiring to Rear Lights

[Magic01]

Hi all

Still new to this T25 ownersgip and only my 3rd post

I'm in the process of getting my van ready for MOT and trying to fix a number of issues

I have a rear indicator light that doesn't work and after investigating I have this unusual wiring that I was hoping someone might recognise? There is also some strange little black box?



I have read many posts on here and my Haynes manual so think I know all of the colours that should be from the light loom to the 6 terminal connectors on both the right and left side light boxes. However mine seem to be a horrible mess to be fair all of the wiring is a mess I have no engine junction box which I'm trying to reinstall.

Here is the mess of my junction box too so please feel free to pass any comments on this mess too



Any help gratefully received, thanks.

[Mocki]

The first picture shows previous muppettry installing a towbar , all the scotch botch lock things are your problem
What i would do is cut all that bad mess out and repair with good soldered heat shrink protected jointing to reinstate the loom to a working state .

As for the black box , all you appear to be missing is infact the plastic box , which you will be able to get from one of the many breakers , just put a wanted ad in the classified section

Actually you maybe as well to try and buy a complete new lighting loom, they unplug at the round cylinder plugs you have hanging that should be in the black box you dont have

[Magic01]

Hi Steve

Thank you for the quick reply I did wonder if it was a towbar/trailer bodge!

I actually have a new rear lights loom so think I will just replace the lot with that as you suggest and start again!

As for the black junction box I have bought one of those too to fit, the only real issue I can see is that there is no live feed from the alternator/starter motor to the relay/manifold heater?

I also have a very thick brown wire that is just taped off you can see it in the picture I have no idea what this is??

[Mocki]

Ok, so i cannot know what the thick brown wire is , you will have to trace it back , it may well be the feed for the live stud in the black box you dont have …….zooming into your picture i noted :
That red wire ( arrow 1) should be connected onto that stud , giving the live feed for the relay for the manifold heater

Arrow2 point to the bleed screw on the thermostat housing, which if it isnt leaking air in , is a problem waiting to happen .
Arrow 3 points to a very dirty bad earth point that will have an effect on the ignition circuit if it isnt already a problem

[Magic01]

Thanks for the feedback

I will trace the brown wire back to see where it leads to.

If I have understood you correctly Arrow 1 for the red wire should be connected to the stud in the black box and is missing the live feed to it (possibly the brown wire) or missing all together. I'm guessing at the moment that relay for the manifold heater isn't doing anything as its got no power going to it? Is this a big issue?

Apologies I don't understand the issue with Arrow 2? The bleed screw does not move at all to be fair, what is the potential future issue here?

I did notice the bad earth point from Arrow 3 today although I haven't worked out what it earth's yet, I haven't had any ignition problems that I've noticed, but will clean it up or replace it accordingly.

[Mocki]

Yes the red wire is currently earthed out to the body , should be onto the live stud in the plastic box , which will also have a live feed from the alternator onto it . Which maybe that brown , maybe not

The bleed screw is a potential cooling system weak point , i wouldnt trust it !

The earth point on the head is where the ignition module earths

[Magic01]

Super thank you always more work and investigation to be done!!!

Are there any issues apart from real cold starts with not having the relay wired in? It isn't at the moment and I haven't noticed any issues, famous last words I know!

When you say you wouldn't trust the bleed screw does that mean you would update it and change for a new housing or remove altogether some how? I don't think I've ever seen one of the later types without the bleed screw as I say it is sealed solid at the moment and won't even budge at all!

[mioba]

Ahhh the joys of T25 ownership and cleaning up a mess.
The wiring is old and many terminals you will see just break in your hands.
Clean all connections, new terminals and a dab of grease to prevent moisture
ingress
Those connectors - yuck.
I found a handful of them behind my dash - all out and wires soldered.

Doesnt answer your qu but a tip.

[Mocki]

I would be replacing that thermostat housing top , the bleed screw isnt really crucial , but it not suddenly leaking is and it looks like it isnt to be trusted imho .

As for the manifold heater , yes, you’ll need it when the temps drop close to and below freezing , Mr VW wouldnt have bothered with it if it wasn’t needed . Yes you will maybe get by without it , but for the minor amount of effort and cost involved in sorting it , its not worth the hassles further down the line

[Magic01]

Hi mioba

Yes, these T25's really are the gift that just keeps on giving aren't they!

Luckily I have some recently purchased wiring looms that I can replace them with so that will help as will check them all out of the van and change/update any parts that need it.

Thanks for the tip on grease, interestingly I have just bought some dielectric grease so hopefully this is the right sort of grease to use on the connectors to prevent moisture ingress

Was also going to use it on the ground connections to prevent corrosion.

[Magic01]

Thanks again Steve

I will look to replace the top of the housing then so will still have a bleed screw but will be newer and hopefully not likely to fail.

As for the manifold heater I will sort it but was just checking that it isn't crucial.

I have a number of other things at play, like a weber carb that I need to get my head around and at some point someone has put in manual points and removed the electric points so different dizzy/Coil as well. So trying to work out with all these changes how everything interacts with each other vs the factory fit.

Also trying to work out my priorities and list of urgent jobs vs good to do etc.. but point noted and added to the list.