Alternator load sense wire

[t140pete]

I know this has been covered a thousand times, and I apologise to those that have already described the procedure, but having done this this afternoon I thought it might be helpful to newer members to see how straightforward it is to sort out this problem.

 

My symptoms were: ASR light coming on after 10 mins then could not be switched off until engine restarted, and alternator not seeming to charge until car had been revved a bit (noticable in this weather by the fan speeding up). The battery symbol was not showing in the dashboard when ignition on (engine off), and a final confirmation was no voltage at the alternator connection with ign. on (eng. off).

 

After searching this and other forums for info, the main suspect was the "load sense wire" located beneath the starter motor - a common VAG fault caused by pennypinching and saving an inch of wire :( 

 

In preparation I bought a connector from eBay (VAG part # 1J0 973 722 ?) and soldered appropriate coloured wires in place, using approx 6 inches to allow for corroded original wiring.

 

I got the front end up on ramps, and removed the undertray (T20 Torx screws - 9 off), the wires and connector are beneath the starter motor, front nearside (UK) of engine bay. As can be seen from the following images, the wires were indeed both snapped clean off, and corroded. I had to cut back the wires about an inch to get to clean copper (not green muck), which made joining these to my new connector & wires a little bit tricky (best method is soldering these together then sealing with heat shrink tubing) but patience and perseverance pays off. Once correct operation was confirmed, all was wrapped up, tied away (not too tight lol) - now working as it should

 

There's no need to be all the way underneath - to get a good view I only had my head approximately in line with the wheels. You could use crimp connectors, or even a terminal block, but expect to have to do it agail some time in the future. You could also bypass the connector altogether.

 

Tools needed : T20 Torx bit/driver, gas or 12v soldering iron (or mains if accessible) and solder, penknife or wire strippers, heatshrink tubing and tape/cable ties

Anyone wanting to do this should be able to do it well within an hour, brews optional. Make sure you trim the wires back to clean shiny copper before soldering, and be careful as it's a tight spot and solder drips hurt - use eye protection and make sure the back wheels are chocked. Safety first ! If you're out of your comfort zone, any competent mechanic or auto electrician will have this sorted in a jiffy.

 

Hope this is of help.

[elaasi]

Hi, soo...quick question. I had the same issue, and when I looked at the gable, I realized that it was already once fixed, but unfortunately, the new piece of cable, were of really bad quality so I decided to fix it temporarily (without soldering, fast re connection and isolation) until I get a new connector (that comes with new wires);  But now something new's happening, at the ignition (engine off) still no battery but no weird lights on (like power steering, or airbag, etc.) but after I turn the engine on, the battery light comes up, goes out, usually at low RPM. Now my questions, a new proper connector will solve my problems, or there's something more to it? As well, I tried to check continuity from the alternator to the connector and I hadn't had any, is that normal?

 

Because the current connector itself was ok, but the cable, the new part, was totally garbage, all of it was rusted and just destroyed, I tried my best to connect (just connect) the broken parts, and check the continuity on the cables - there was - but...when I get the new connector, I will cut from above where it was previously fixed....

 

Edited 26 January, 2020 by elaasi