Light machine faulty?

Hello dear community,

The fan belt on my 2.0L 136 HP diesel engine has broken. Has completely gone off the rails...

I have then installed a new ABS unit and replaced the gear drive belt. The battery was charged, and everything seemed to be working again. Then, during the first kilometer of driving, it suddenly displayed an ESP error. I drove another 5 km, then parked the car and drove home several hours later. On the way back, the ESP error appeared again. After turning the engine off and on again during the drive, the error disappeared.

The next day, I drove another few hundred meters. After a short stop and restart, the battery was already noticeably weak. I had covered about a kilometer when the servo failed while turning...

Since the belt was still driving the alternator, I thought the alternator must be broken. Measuring at the battery showed a very low 11.9 volts. I had forgotten to reconnect the charging device, including the car's contacts, when I installed the alternator. As a result, there was a spark when I accidentally bumped something near the installation point with the alternator. I thought that must be the reason why the alternator was broken.

Subsequently, I obtained a used alternator and, as expected, there was no change... 11.9 volts at the battery. I then measured from B+ to battery negative... 4.9 volts. B+ to alternator housing... 4.9 volts. B+ to Engine Block...4.9 Volt.

When the engine is turned off, I measured 10.5 volts on the B+ line with a battery voltage of 12.5 volts...

Is the second alternator now also broken randomly, or could there be something else?

Does the charging indicator light up?
Whether your used alternator is actually defective, no one can tell you for sure; it was probably cheap.

B+ is the positive terminal of the battery. If you don't measure the battery voltage there, then the cable is broken.

Most likely, there is a fuse somewhere that tripped due to your initial short circuit (fortunately).

Greetings
Guste

Fuses are typically located as strip fuses directly on the battery.