More Wiring Woes. Alternator D+ connection plug

[SammoVWT]

Ugh. Old wiring is the bane of my life right now.

Ok so heres the siutation... alternator output good, 00532 alarms were pinging up on 6-10 (high intermittent) on both the ECU and airbag. Cleared those.

Inspected all wiring, ground points, all clean good etc. Even resat alternator regulator and installed a second one - same issue. Pulled apart dash to check wiring from the new ignition switch. All fine.

Went back to the bay and noticed my D+ wire going between the switch and alternator (yes, the blue one) had many bits of copper showing around all the connectors. The worst one was the socket near to the exhaust manifold/starter. Wiring frayed - hence intermittent connection.

I was going to repin the plug, but I was left in the middle of Tescos garage with an overcharging alternator due to a completely dead D+ connection. So.. I lopped out the bad connector after much wiggling, resitting and praying it would re-connect to get me home. No joy. Not that lasted anyway - so I fitted a new plug with some freshly pinned spade connectors (pinned it myself - lucky I had some spare in my toolbox). Wrapped the whole new connector with electrical tape through sheer paranoia of developing this again.

So this is the fun part. While I was inspecting the rest of the wire, noticed the D+ wire is also showing copper at the other end at the alternator socket. So, I was planning to re-pin this too or replace with a new bosch connector, or if worst comes to worst, pin a spade connector directly onto the alternator terminal with no socket (really trying to avoid this). But, I have two problems.

1) I have no tool to unpin these bosch connectors.
2) I have no idea what the part number is for the bosch connector to buy a new one to re-pin/connect.

So I am here to ask for help - been trawling the interwebs high and low trying to find the connector - but they are all the wrong size.

In the hope of help my alternator is 028 9030 025 h - has a bosch 2 pin socket/connector combo, but only 1 pin/wire is used (no alternator tacho monitoring). Can anyone help me find the correct bosch socket?

Thanks in advance, trying to avoid doing a sloppy fix. (This socket is still giving me intermittent connections occasionally, would love to avoid a battery fire).

[SammoVWT]

Bit of an update:

I think I found the part number after some more digging. Hopefully will be of use to someone else

Bosch: 1 928 401 920 - now I just need to find some junior pins or a connector kit and a supplier.

EDIT:

Now im on fire: 2- napainen liitinsarja, Jetronic, pikalukko sivuilta irroitettava, 0.5 - 1.5 mm - Electrical Connectors 2 pole connector sets with pins and seals connector kit. Im sure i'm not the only one with wiring issues.

Edit 2: Waiting for someone to get back to me regarding the exact part - but ordered some generic what I now know are called junior power timer terminals to check for fitment

[SammoVWT]

Ugh the plot thickens.

I replaced the broken connector today by repinning a new one on.

In my excitement I noticed the battery light wasnt on and assumed it was charging the system. I was incorrect.

So I checked voltage down the blue wire to the alternator and I have 12.05V showing all the way down to the connector pin at the plug end. This is lower than my battery voltage (12.5V). Alternator not charging (12.3V while running) and no battery warning light showing.

Also which is of note, the battery light on my dash seems to have stopped working. I have the ignition on and car off, but no battery light is showing (bulb gone?).

This charging issue is making me lose the will to live. Not sure where to start next. I can't need another new regulator surely when it was a mild overcharge surging?

I even de-pinned the plug and put the female socket straight onto the pin of the alternator. Checked the voltage while connected - still 12V with ignition on, still no charging. Not sure what to do next. Assistance is most welcome.

[SammoVWT]

Not sure what to do now, I just ran a fly wire from the plug to the alternator casing with the ignition on and the battery light lit up on the dash. So that circuit is working.

So now I either have a broken regulator, or the connector plug going on the alternator itself is damaged. I might just pull the alternator off and take it a part to look. Fun times.

[SammoVWT]

Right bench pulling old nessie the nasty alternator, going to see why I havent got a ground connection. Will post back with grubby pictures!

[SammoVWT]

I could have sworn I was going crazy. Never had such nonsense with a voltage circuit before. Right so I have 100% proofed the wiring from the ignition switch to the plug end - I have tested the female plug end attached to my new exciter loom by touching it to ground (with ignition on), and the battery light pops up on the dash (hurray).

Cleaned up the regulator contacts after removing the alternator to be 100% sure, but same issue - even plugged the female pin directly to D+ on the alternator incase of incorrect plug fitment. Still nothing. No battery light no charge. So.. either my D+ is physically open, or my regulator has gone open circuit. I have no voltage drop between alternator casing an battery post also, and no voltage drop B+ to battery+.

I did a resistance check from D+ regulator D+ connector pin and there was a connection, I.e. no open and a smallish resistance. So I believe the physical socket is OK.

So with any luck, its just a bad regulator.

Will fill the thread with pictures later. Worst case I will need a new alternator... best case this new vemo regulator will fix all my ill's and I will have no more overcharging/non-charging problems.

What a day.. I just hope it works - tuesday at the latest apparently. The duff regulator is a Meyle one, which was surprising - so hopefully just bad luck.

[SammoVWT]

Hurray. My qualifications werent wasted.

After waking up this morning a little sad because I couldnt drive the old girl until tuesday afternoon at the earliest. I wasn't sure what to do. I had a coffee, a think and realised that I keep my old components for a reason. Hastily went to my toolbox and there it was, my old original bosch voltage regulator. Almost worn to the nubs, but this should prove the fault beyond doubt. Regulator failure.

So.. despite being rather battle hardened and worn, I loosened up the alternator, slapped the old regulator in after a liberal polish with some contact cleaner. I removed the old original wire from the new plug I made. Ran the tested good new wire I ran yesterday into the pin. Quickly re-fastened the cables so I can test my 'home made' socket Plugged the pin into the connector. Tested battery light with a paperclip and earth connections in the D+ wire. Voila, connection still there. Steady volts. A well done moment.

Plugged in the harness onto the alternator. Turned on ignition (with the old regulator), I couldn't help but cheer when I saw that red battery light - my neighbours must think i'm a bit crazy. Started the engine - light went out.

Cracked it. So I've now fastened everything up properly and cable tied the new wire to the alternator down. Voltage tested the alternator output. Initially 14.4V (expected as I had been running on battery power only), but very quickly dropped to 14.2, revved the engine with the meter connected and it was holding steady much to my surprise. A rock steady 14.2. The new one didnt do that, there was always a fluctuation slightly, but not enough to concern me.

So there you go kids. Theres a lesson in here somewhere. Glad I didnt condemn my alternator which I was almost certain of doing yesterday. Now I have a few days of being able to use the car until my new regulator comes. The smile has returned, and I don't want to jynx myself, but I think my old golf is now electrical fault free, with the exception of some window motor brushes I need to get to.

I might faint.

[SammoVWT]

Confirmed Fixed. SWMBO demanded that I play taxi-driver yesterday - which resorted to me having to drag the car to pick up a regulator locally on saturday against my better judgment to avoid a breakdown on the motorway from a worn out brush. So now I have a spare on the way.

Did a bunch of voltage and load/rev tests. Compensating perfectly vs temperature, voltage, draw and engine RPM. It hasn't missed a beat. No overcharge, no undercharge.

Once I get some time I may put up some extra pics to show extra loom points of failure. Not so much the loom (some of it at least as I found), but the brackets that hold them in place which tend to be the root cause of this. Since mine seem to have aged and cracked off, its important to check for anywhere in the engine bay which leads to cables rubbing against metal also.

Cured a lot of my intermittent issues which never trigger an alarm. Will MS paint the areas too. Will bust the camera out after work - hope it will help someone else by short-cutting their time down. Heat and vibration - a looms worst enemy.

So.. with that being said. All gremlins are now gone. Car runs smooth and on the money, no stutter/flutter/odd loping/missfire etc - all gone. I might be able to focus on tidying her up now. Two solid weeks (well evenings and weekends), tracing, testing and repairing wiring, replaced ignition switch and clock spring. Worth it though although I did nearly want to torch the thing last week. So much love hate with this car. Now I love it again.

Shouldnt complain too much. It is 20 years old and I should expect it really.

[niall campbell]

what make of regulator did you put in it to replace the Bosch ?

[SammoVWT]

The replacement was a meyle/topran - this one was broken.

The second was a non-branded german part - let me check the invoice to see what it says, I did read the stamp on the back of the transistor block but it was just the regulator spec. Gimme a couple of mins will run to the car and grab it. Cost me £28+vat

Edit: Invoice isnt very forthcoming - has their part reference on it 46470 (looks like it might be a autopulley one - but I can't be sure), however I got it specced against bosch part number: 028-903-803/d - the genuine bosch one is £68.00+vat

Edit 2: Also finished up with the photos - will start adding them later on after work