Information Electrical - A2 earth points

Birchall

Dick Chown Award 2016
I have not yet checked the eart to the starter but did try to undo the bolt to the body behind the ABS pump but is very tight so think will remove the headlamp and try again.
That is the one i mean.

The bolt can simetimes sheer off but off but there are other points on the body that you can use if it does.

Steve B
 
Sorry for dragging up an old thread. But thanks to the power of others knowledge..

Having had a few problems recently I looked at this thread and thought as mine is a 2003 model I shall investigate if this could be the problem.

Today I removed the old cable to look under the sleeve and hey presto THE PROBLEM !! IMAG0124.jpg
 
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Behind the n/s headlight attached to the body.. If you remove the headlight and look at a 45° angle you should see the bolt with the cable.
 

cheechy

Member
Sorry for dragging up an old thread. But thanks to the power of others knowledge..

Having had a few problems recently I looked at this thread and thought as mine is a 2003 model I shall investigate if this could be the problem.

Today I removed the old cable to look under the sleeve and hey presto THE PROBLEM !!View attachment 44857

I think I may have to look at doing this whilst i have some time off. I obviously know where one side is (under headlight) but how much of a job to completely remove? Do I have to get under tray off not sure where it goes?

I'm aware of a number of earthing points on the car but this is related to temp flap motor and slightly rough starting so I'm edging towards a damaged earth cable...I've already cleaned up and replaced the washer
 
Cheers Sarge ! little surprised when I found it, I thought I was looking for a small item the ccu, full of surprises my A2. I also found diagrams in there which I will post later for all. Might as well be foreign language to me but I'm sure someone will decode.
 

Andrew

A2OC Donor
A snippet of information to add to this useful thread.

This week I detached the earth point high up the left hand A-pillar under the quarter light (my dash is off), see the pictures in post number 9, to gain better access to the big loom below it. I also had the big connector on the ABS unit off and out of interest thought I would test with a meter continuity between the two biggish earths that serve the ABS unit and the detached earth. Sure enough continuity on both ABS earths, so this earth serves the ABS unit. Now you will notice In the pictures two biggish earths at the body bolted earth end and two biggish earths arrive at the the ABS unit. My money is on this body earth point exclusively serves the ABS unit.

Andy
 

Howey

Member
A snippet of information to add to this useful thread.

This week I detached the earth point high up the left hand A-pillar under the quarter light (my dash is off), see the pictures in post number 9, to gain better access to the big loom below it. I also had the big connector on the ABS unit off and out of interest thought I would test with a meter continuity between the two biggish earths that serve the ABS unit and the detached earth. Sure enough continuity on both ABS earths, so this earth serves the ABS unit. Now you will notice In the pictures two biggish earths at the body bolted earth end and two biggish earths arrive at the the ABS unit. My money is on this body earth point exclusively serves the ABS unit.

Andy
I have an intermitent fault with ABS and at the same time indicators dont flash just stay on constant when activated!
Have already fitted a additional engine earth but wonder if these two body earths could be a potential cause to my occasional faults (have always cleared with cycling ignition so far)
 

tbc

Member
I think my TDI seems to have an earth problem seems fine when starting from cold and left for for a number of hours but when driven then switching off then trying to start the car it stuggles to start almost like battery is flat turns over slowly and faults start flagging up on dash , battery seems to have enough power in and alternator is charging about 14v .
I have this problem with my 1.4, starts fine and you can drive for miles, the engine running and accelerating fine, then the windscreen wiper will move by itself when switch off and the car will chug twice. If you stall or turn the ignition off it won't start, no battery light but almost like you have a flat battery.
 

Robin_Cox

Member
The part numbers needed (if new required) for the starter motor earth behind the passenger headlamp are......
Bolt - N0901484
Washer - N01152426

http://www.partsbase.org/audi/audi-...attery-wiring-set-for-three-phase-alternator/
Ta
Dave
:)

To update this post in 2020 - the above link is no longer valid.

However, I found the equivalent 7zap page here with the part numbers for various starter / alternator earth & loom-related components :


For reference - the part numbers above refer to another connection (M6) bolt (part 22 on the 7zap diagram)

The starter motor earth bolt I was working with is 8mm with a cognate washer (parts 23 and 24 on this diagram)
p/n N90520201 (possibly updated by VAG to N90520202).
 
I found the earth point from the battery today. It’s behind the carpet just inside the rear left hand door. The plastic door trim is really tricky to put back, but I recon you could successfully just pull the corner of the carpet out. It’s the same size 13mm head bolt and washer as the earth point behind the headlight. It was in reasonable condition, but slightly corroded. A quick clean and grease, and all seems well. This was the last earth point to clean, and even so I think it did slightly improve the starting.
 

Ami

A2OC Donor
I found the earth point from the battery today. It’s behind the carpet just inside the rear left hand door. The plastic door trim is really tricky to put back, but I recon you could successfully just pull the corner of the carpet out. It’s the same size 13mm head bolt and washer as the earth point behind the headlight. It was in reasonable condition, but slightly corroded. A quick clean and grease, and all seems well. This was the last earth point to clean, and even so I think it did slightly improve the starting.
Hi:
do you have a picture of this, I am having a lot trouble with what seems to be a short circuit across +ve & -ve upon cranking the engine, the battery voltage drops from 12.8 volts down to 5.5 volts, have replaced, starter, cable behind headlight, battery. Have had lots of advice with thanks to @audifan but just can not locate the short circuit, it happens upon cranking the ignition/engine as mentioned, which stops the car from starting. it was hard to start but gradually got worse, I can put two batteries in parallel & start the car, but even that not always work.
Maybe a Relay somewhere causes the short when turning the ignition, its doing my head in.
Cheers,
Ami
 

kp 115

Member
Hi:
do you have a picture of this, I am having a lot trouble with what seems to be a short circuit across +ve & -ve upon cranking the engine, the battery voltage drops from 12.8 volts down to 5.5 volts, have replaced, starter, cable behind headlight, battery. Have had lots of advice with thanks to @audifan but just can not locate the short circuit, it happens upon cranking the ignition/engine as mentioned, which stops the car from starting. it was hard to start but gradually got worse, I can put two batteries in parallel & start the car, but even that not always work.
Maybe a Relay somewhere causes the short when turning the ignition, its doing my head in.
Cheers,
Ami
Hi AMI,
Have you checked the starter for a winding going down to earth?
If you have a spare bench test it fed from the car, after securing it to the said bench.
Hope that is of help.
Keith
 
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Ami

A2OC Donor
Hi AMI,
Have you checked the starter for a winding going down to earth?
If you have a spare bench test it fed from the car, after securing it to the said bench.
Hope that is of help.
Keith
Hi Keith:

I have changed the starter motor and the earth cable, there is a short circuit upon cranking the draws the battery voltage down to 5.5 volts, but if you just turn the ignition without cranking, there is no volt drop, it seems a relay or something finds itself to earth when trying to start, never seen this in 45 years of driving, very odd.
Cheers for your input,
Ami
 

kp 115

Member
Hi Keith:

I have changed the starter motor and the earth cable, there is a short circuit upon cranking the draws the battery voltage down to 5.5 volts, but if you just turn the ignition without cranking, there is no volt drop, it seems a relay or something finds itself to earth when trying to start, never seen this in 45 years of driving, very odd.
Cheers for your input,
Ami
Does sound like a fried relay then
 
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Ami

A2OC Donor
Fed directly from battery small red wire 10mm according to Jigsaw
Se A2A2 post

HELP! 1.4TDi not starting​

Just tried removing the alternator belt in case the tensioner/alternator/air con pump are seized up but all 3 were fine turning easily by hand, dont know where else to check, when cranking the engine, the voltage drops & the earth wire on the battery pack very warm.

No idea where else to look !
 
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