Brake Pad Wear (+ABS) Cable Repair Kit - 8Z0 927 904

Hi Andrew,

I do a fair amount of wiring on these, honestly for this sensor I would just get a good quality crimp or soldier on the old wire


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Back to it later today but I am well aware any earth will do and in fact the simple neat solution is to use a ring terminal on the big convenient earth bolt at the foot of A-pillar. I have nothing against crimped connections, in fact every wire on the A2 has crimped connector pins but to a much higher standard that I can achieve manually, I just want to use the repair kit as Audi intended. With its long leads and pre-crimped connectors they must have an intended repair plan but the yellow wire is a puzzle.

Andy
 
Back to it later today but I am well aware any earth will do and in fact the simple neat solution is to use a ring terminal on the big convenient earth bolt at the foot of A-pillar. I have nothing against crimped connections, in fact every wire on the A2 has crimped connector pins but to a much higher standard that I can achieve manually, I just want to use the repair kit as Audi intended. With its long leads and pre-crimped connectors they must have an intended repair plan but the yellow wire is a puzzle.

Andy

If you need a good crimping tool with nice crimps that heat shrink these are great.

Lolypot Crimping Tool Cable Ratchet Wire Terminals Crimping Plier Kit Hand Stripper Crimper Tool with 200 Pieces Heat Shrink Butt Connectors 0.5-6mm² https://www.amazon.co.uk/dp/B07PDLNZG3/ref=cm_sw_r_cp_api_i_0k9YEbEQW433E

Now I’ve also used these a lot and when done right, the results and very good can take a few tests first. Get them nice and hot even a lighter will work although best with a heat gun, but make sure you don’t under heat.


50 Pack Solder Seal Wire Connector, Heat Shrink Butt Connectors Insulated Electrical Solder Sleeve Terminals Waterproof Marine Automotive Butt Splices


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If this is to fix the brake pad wear circuit, just disable it by short-circuiting the circuit.

The pad wear sensor does not makes any sense being applied for 1 wheel only, and being on this forum I assume you have somewhat of a montly feeling (check) of the pad thickness. Furthermore the car is subject to regular MOT where pad thickness is one of main test items.

-> nothing to worry about
 
I need to do this job and have the long cable* and was thinking of pushing it through the bulkhead alongside the main cable and fishing it out behind the glovebox. But looking at the photo above with the dash removed, that doesn't look possible because of the pre-moulded tunnel .

Looking at the photo of the engine bay (above - thanks's Andrew), there is a triangular (?) panel with 2 bolts visible. I guess that is the ventilation tunnel. Could one slacken the nuts and push the cable through there. Key thing is: can it be accessed inside the cabin behind the glovebox?

Any thoughts?.

*actually, I also have the short cable repair kit that is spliced in but then the long cable kit became available at 1/2 price so I bought it.
Hi,

Getting the cable through the bulkhead is not easy, both of your ideas give the impression you think you can reach up behind the glovebox and retrieve the cable on the cabin side. The glovebox is no problem you can simply pop that out, the real problem is the big lump of air con hardware behind the glovebox and the bulkhead wall, it makes most things impossible.

Yes, the triangle you refer to is the right hand side of the fresh air intake from the bonnet. If you do as you describe you will be blocked by its counterpart ducting on the cabin side. You could possibly get a cable through here by drilling a hole 1 cm to the right of the bottom nut, I would never advocate it, and anyway the supplied wires will be too short owing to the detour. It is just accessible on the cabin side, but strongly advise reconnaissance first and make a bed like mine for comfy access!:)

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If you want to use the long lead, I think no option except dash out, hours of work.

Andy
 
Can you use a piece of semi rigid rod, i.e a straightened metal coat hanger and tape some string to it. Pass that through the bulkhead area. Once inside untie the string form the coat hanger and then tie the loom to the string and carefully pull it into the cabin. I have fed numerous wires and cables through inaccessible areas in the past with this method. My preferred rod is a stainless steel welding rod.
 
If you want to use the long lead, I think no option except dash out, hours of work.

Thanks Andy. Maybe time for a rethink. I wonder just how may on the full kits were fitted if the dash has to come out.
Whilst a solder or crimped joint might not be a perfect solution, any failure is going to fail safe - i.e. a false positive and as mentioned, it's easy to check the brake pad wear.
 
Can you use a piece of semi rigid rod, i.e a straightened metal coat hanger and tape some string to it. Pass that through the bulkhead area. Once inside untie the string form the coat hanger and then tie the loom to the string and carefully pull it into the cabin. I have fed numerous wires and cables through inaccessible areas in the past with this method. My preferred rod is a stainless steel welding rod.
I have the wires already through the big grommet, it might look fearsome but actually it is thin and compliant with spare capacity, no problem using a method similiar to what you described. My last post was for Alan who had designs on not removing the dash.

Andy
 
Unless the dash is being changed that is a hell of a lot of work. Have you now got all your connection points sorted. There is no independent earth in the headlight assemblies that I can see, so the earth must be part of the wiring loom into the headlight. I thought there were 5 functions there are actually 6. Indicator, sidelight, headlight, main beam and leveler up and leveler down. Yes there are 10 locations in the plug and only 9 occupied. Only question without really studying the wiring diagram is are the pins for 6 live feeds and 3 earths or 5 live and 4 earths ( leveler switching the earth or the live feed ) . Ultimately you will have a neater job by replacing the whole loom and only having to cloth tape the earth into the headlight plug.
 
I have gleaned some snippets of evidence in my hunt for the end of the yellow pad wire and the elusive '119 Earth connection -1- in headlight wiring harness'.

I do know the old yellow wire is grounded somewhere. Evidence: my meter finds continuity with any bare metal on the car and the yellow wire tail in the engine bay, in fact the shiny metal on the exposed centre console area is good for this. Also continuity with lots of pins in the connectors at the base of the A-pillar, they must simply be other earths.

I had an idea! The yellow wire will be earthed via one of the chunky principal earth points bolted to the car. Find which one and try and trace it until I encounter my yellow wire connection.

Did not take long to find which earth, started with the bolted earth point at the base of the A-pillar, unbolted it and bingo! continuity between the yellow wire and car body vanished. Conclusion: the yellow wire is earthed via this earth. The other A-pillar earths also went dead.

Interestingly, with the big earth detached I have continuity on 4 pins in the connector (detached) of the left side headlight and yellow wire. This is in accord with the wiring diagrams.

Now I try and trace this big earth and it gets bizarre. The big earth seems to leave the base of the A-pillar making no connections there! and disappears back into the engine bay away from the pins it is earthing at the A-pillar!

SAM_4245.JPG


Once through the big grommet it drops down over the wheel arch ..

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..and appears to go straight to the power steering kit!!!!!!!???
power-steering-pump.jpg

This is not my car but notice the fat earth.

Could this group of connectors be it??☹☹, some kind of earth strip across all three? The only problem is I can't get at without taking the bumper off:mad:.

One point worth mentioning. As Edward commented above and I had noticed the wring diagrams show a lot of kit use Earth 119, predominantly at the front of the engine bay, (or logically connected to it, eg. Climate), radiator electrics, headlight, headlight washers, power steering...I feel I am getting warm.

The hunt goes on.

Andy
 
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Looks promising, the mystery is unraveling.

image.jpg


Some kind of multiple earth union hidden in the loom, will investigate further.

Andy
 
This is called a loom weld and yes there are loads of these normally in the loom


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I had heard of welds but I now assume that is a generic term as it is in actual fact a large crimped connection, done by a tool/machine that can exert a lot of compression. Five earth wires join the main bolted A-pillar earth here.

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Thanks for the continued interest.

Andy
 
I had heard of welds but I now assume that is a generic term as it is in actual fact a large crimped connection, done by a tool/machine that can exert a lot of compression. Five earth wires join the main bolted A-pillar earth here.

View attachment 64996 View attachment 64997
Thanks for the continued interest.

Andy

I don’t know why they are called welds but everything is a mechanical connection in the loom no solder, as crimps are stronger long term.


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How I found the weld was by back tracking. The power steering earth was inaccessible to see if any other earths branched off it, and it was getting too far fetched anyway as a line of enquiry. I think I commented I found, with the big bolted A-pillar earth detached, four of the pins in the left headlight connector still had continuity with my yellow pad wire. Idea: trace these headlight wires and I will encounter a connection with my yellow wire. Almost instant dead end, found they also disappeared through the big fat grommet at the top right of the engine bay and did not arrive at the base of the A-pillar. Something is going on with the big loom as it drops down from the fat grommet cabin side to the foot of the A-pillar, inspecting it I found by FEEL this weld, it was out of sight round a bend, everything is making sense now, hindsight is a wonderful thing!

Downside is my yellow wire is not part of the weld ☹ , the hunt goes on.

I have spotted a bulge in the big loom just below the quarter light window!!!

Andy
 
A little tug of the old cable in the engine proved in my mind this was indeed my yellow wire when some slack with the yellow cable was taken up, took the plunge and cut it along with the old red wire. After a little persuasion the old cable pulled back out into the engine bay including the brown and black ABS wires. So for the record, answering my own question in the first post, yes the brown and black ABS wires while still within the thick outer casing head first through the big fat grommet into the cabin, once the outer coat finishes they do a U turn and come straight back out of the the big grommet back into the engine bay and head for the ABS unit via the upper loom, a bit of a bizarre route.

My curiosity is satisfied, just got to connect up the new cable and tidy things up.

Never got to the bottom of '119 Earth connection -1- in headlight wiring harness' , unless it's simply the second weld I found.

Andy
 
I'm glad you sorted this in the end and for sharing your efforts with photos. If you took the dash out just for this job then my hat off to you; very admirable. I've chicken out and will be using the short repair cable.
 
I'm glad you sorted this in the end and for sharing your efforts with photos. If you took the dash out just for this job then my hat off to you; very admirable. I've chicken out and will be using the short repair cable.
Yes, certainly easier (non lunatic way!) to splice in the engine bay, but I did have other reasons for removing the dash.

Only the red pad sensor wire needs to go through the bulkhead, the yellow earth wire can be earthed anywhere in the engine bay, passenger headlight would be a good candidate and the two ABS wires can route directly to the ABS unit. It would still be messy with the repair loom Audi provide because of the excess of wrie lengths unless they are shortened but you would need crimping/soldering skills for new ABS terminal pins and a source for them.

Andy
 
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