Golf 3 TDI AFN Engine: Won't Start?

Hello everyone!!!

I NEED URGENT HELP!!!!!!!!!! My Audi (AFN engine) won't start, and all the electrical systems are malfunctioning – the turn signals, wipers, etc., aren't working.

Here's a brief background! Today, I (having completely replaced the interior of my car, including the side panels and the window switch) modified and rewired the switch and cables for the electric window on the passenger side so that the Golf 4 switch would work. Everything worked fine, except for the LED in the switch! When I was trying to get the LED to light up, meaning I was making some adjustments inside the switch itself, I wanted to test it again, so I turned the ignition on. And from that point on, absolutely nothing works anymore!!! (((((((((((((((((((((((((((((((
The engine won't start, etc... When I turn the ignition on, I hear a 'click' from the climate control system, and (I think) the engine control unit for the immobilizer! I've already checked everything, fuses, etc... but nothing seems to be the problem! My suspicion is that the engine control unit has failed. Can you possibly confirm this suspicion?

I REALLY NEED YOUR HELP!!!! I'm desperate because the car needs to be finished by Sunday, and now nothing is working!!!!

And are you sure the battery isn't dead?
Just revert to the last change you made, and everything should work again.

Don't worry, if the MSG (Motor Control Unit) were faulty, for whatever reason, at least the starter motor would turn, because it's connected to the ignition switch.

The answer is usually found much faster than the post is written. As I already mentioned, dismantle everything that's new and re-check the wiring. Also, take a look at the relevant fuses and relays to see if you might have accidentally damaged anything.

Okay, as I may have already mentioned, you might have simply consumed too much power during the renovation (lights, music, gadgets), and now the battery is depleted. That's actually quite simple to check and aligns with your description.

@ mserge: no, the battery is weak, but not completely dead! I even connected a large, fully charged battery in addition, using jumper cables, but I got the same result .
Yes, I've already done that! I removed the Golf 4 switch again and reconnected it in the original Golf 3 configuration.


@ matthiasTDI96: yes, the starter motor is also turning! As soon as I try to start the engine, it turns and tries to start the motor, but it doesn't maybe it's a faulty engine control unit (ECU) ???
As I mentioned, I removed the Golf 4 manual transmission and reinstalled the Golf 3 transmission, but the problem persists.

Bitte gib mir den deutschen Text, den du übersetzt haben möchtest.

Okay, my suspicion is, and I'm now 99% sure, that I caused a short circuit to ground through the Golf 4 switch. Now the question is whether this short circuit, somehow, might have reached the engine control unit, or perhaps a cable somewhere might have melted, causing it to constantly short to the body.

I'm really at a loss .

Maybe you're just having a problem with the immobilizer?
Perhaps the antenna is not properly connected or is defective?

Sure, Maxx.

IT'S WORKING AGAIN!!!! YAYYYYY!!!!

I likely had a significant grounding issue. Anyway, I connected a cable directly from the negative terminal of the battery to the chassis ground. As soon as that connection was made, everything started working again – the engine started, etc. However, without that cable, I'm experiencing major problems again. To summarize the current situation...

'Strangely enough, everything is working again now, but WITHOUT the extra cable!!! So it's back to how it was before! Which means I'll probably NEVER know what the real reason was, 100%.'

But now I'm happy first!
Thank you to everyone who helped me!

Quote:

So, everything is the same as before! In other words, I will probably NEVER find out what the real reason was, 100% of the time!

WARNING!

You're still having a problem with the ground cable, although it's not happening right now. You should fix that immediately, otherwise, if the battery fails as a buffer, you could experience voltage surges that damage the control units. We had a similar case in my family. In that situation, the ground cable in the terminal intermittently had no connection. We've also had batteries that had no internal connection.

Yes, I understand that! I'll also run a ground cable directly from the battery to the chassis. That should definitely fix it!
What do you think about that?

Neno wrote:

Yes, that's clear to me! I will also add a ground cable directly from the battery to the chassis! Then it should definitely work! Or what do you think about that???

Make it thick enough, at least as thick as the original!

Just take a look at the ground connections. One goes from the battery to the chassis, and the other should go from the chassis to the engine-transmission. Perhaps something has rusted away or corroded. Often, metal mesh straps are used for these, and they tend to corrode over time. Since I'm not specifically familiar with the Golf 3, I can't say with 100% certainty where these cables should be located on your car.

Now, finally, everything is working again! There was also a short circuit to ground, among other things. I have found the cause.

Aber nun endlich funktioniert alles Einwandfrei! Jetzt weiß ich auch wieso das Xenon beim Einschalten immer geflackert hat, und nicht anging! MASS!!!!
Now, let's get started!

I'm really, really happy!