Ignition Problems: Troubleshooting & Repair

Hello everyone!

First things first: The vehicle in question is a Volkswagen Golf 3 TDI (engine code AFN, 81 kW, manufactured in June 1997).
...and I swear that I have used the search function extensively.

Since the beginning of this summer, I've been having major problems starting my car.
"This happens especially when it's hot outside or the car has been sitting in the sun for a long time. The ignition does turn on to level 1, but the starter motor doesn't make any sound. Initially, the starter would engage after 5-10 attempts, but now I can only start the engine when it's cool in the morning. If I want to drive home from work in the afternoon, I almost always have to push the car or let it roll downhill, which is quite embarrassing!"
When I turn on the ignition and disconnect the red 4mm² cable from the starter motor, then directly apply voltage to the starter motor, the engine starts immediately. Therefore, I can probably rule out the starter motor as the source of the problem.
Is it really the ignition switch that's defective, or could there be other causes for this problem? (Immobilizer, sensors, relays, etc.) How can I check this? I don't want to remove the ignition switch prematurely because it's quite a complicated process.
"Especially disassembling the airbag, which I have the utmost respect for... Unfortunately, I don't have a diagnostic tool."


I am grateful for any advice!


Best regards, Olli.

...who really hates pushing his car in the heat.

Before you start disassembling anything, I would definitely recommend connecting a diagnostic tool or having it connected by a qualified mechanic. It's better to spend a few euros on getting a proper diagnosis than to randomly remove parts and waste your time.

"I don't think a VAG-COM will really help you with this. In my opinion, the cause of the problem is clear: somewhere you have a cable connection that isn't conducting properly (due to corrosion or something similar). So, check all the affected cables. A bad ground connection is often the culprit, but it probably isn't your issue since you mentioned you can bypass it by connecting +12V directly from the battery to the starter and it works. Just verschandeln all the contacts carefully."

I would like to try starting the engine in a "Polish" way by...
Disconnect the plug from the ignition switch and bypass it using jumper wires.
Which contacts do I need to bridge for this? Unfortunately, I don't have a circuit diagram.
Do I really have to completely remove the entire ignition switch assembly if I want to replace the immobilizer control unit (ZAS)?

Best regards, Olli.

"Do-it-yourself" repair guides like those often provide helpful information.

Olli76 wrote:

Which contacts do I need to bridge for this?

You need to bridge the connection from the thick, constantly energized cable to the starter cable. The starter cable is located at terminal 50 or 50a on the ignition switch. You should be able to easily identify the constantly energized cable using a test lamp.

A good tip is to consider an alarm system, especially one that was installed later. Do you have something like that? This has nothing to do with the immobilizer.

Regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It can also be used as a verb, meaning "to gust."

@Guste100

However, that would only cause the starter motor to whir, but not start the engine.
It's not possible for the engine to start if the ignition is turned off (engine electronics), right?
A friend recently advised me to get a ZAS (presumably a type of permit or document) from the "friendly" office and to do this...
simply hotwire it and start the engine with a screwdriver.
Once it works, I can remove the steering wheel and replace the ZAS (presumably a component).

What seemed strange to me yesterday was this: When I started the engine "manually,"...
"When I turn on the ignition, disconnect the red 4mm² cable from the starter motor, and apply voltage directly to the starter motor, the engine starts immediately..."
"The starter motor was running along with the engine, which was clearly audible when I restarted the engine."
"When I turned off the engine, the starter motor continued to run for about 3 seconds. However, this is normal behavior."
The starting process is not initiated by turning the ignition key. Therefore, the ignition switch must have other functions.
Connect with contacts?

Olli76 wrote:

However, wouldn't that just cause the starter motor to whir, since the engine can't start with the ignition (engine electronics) turned off, right?

Okay, the ignition is working, but. You can turn it on using the ignition key, and then you need to create a connection between terminals 50/50a in addition to activate the starter.

Olli76 wrote:

A friend has now advised me to get a ZAS from the "friendly" place, and this... simply hotwire it and start the engine with a screwdriver. Once it works, I can remove the steering wheel and replace the ZAS (presumably a component).

Sure, that's possible. The question is whether the seller will simply accept the return of the ZAS. Electronics are generally excluded from the right of return. However, some sellers may be willing to negotiate. I would definitely inquire about this beforehand. (Otherwise, malicious people might return a defective ZAS.)

Olli76 wrote:

When I started the engine "manually," "When I turn on the ignition, disconnect the red 4mm² cable from the starter motor, and apply voltage directly to the starter motor, the engine starts immediately..." "When the engine was running, the starter motor continued to run with it, which was clearly audible when I turned off the engine; the starter then ran for about 3 seconds after that. However, this does not happen during my normal starting procedure using the ignition switch. So, the ignition switch must be switching other contacts as well?

Nö, keine weiteren Kontakte. Hast du das Kabel zum Anlasser denn auch wieder abgenommen, als er angesprungen war, so wie du normalerweise den Zündschlüssel nicht ewig in Startstellung hälst? SonIt's clear.

If it's stuck, either the starter motor was already engaged through the ignition switch without you noticing, or it engages intermittently. The cause is likely a lack of lubrication in the starter solenoid --> Remove, clean, and lubricate it.

Regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It can also be used as a verb, meaning "to gust."

Okay, so I tried everything yesterday. The ignition switch is definitely...
faulty! Now I'm faced with a dilemma: Do it myself or have someone else do it?
If it weren't for the airbag issue... Has anyone had any experience with that?
"Have you ever had the airbag removed from the steering wheel? Perhaps it was already missing when you got the car."
Did anyone manage to get it working? I've already read the instructions about it.
https://community.dieselschrauber.org/en/viewtopic.php?t=8761
What would the workshop cost approximately? I'm not sure if it's worth my while to attend.
Putting your health at risk, and of course, also the functionality of my airbag if it were to deploy for me...
It's flying around your ears!

What do you mean?

Enjoy your meal! / Have a good lunch!

If only the "on" position isn't working, I would simply install a start button.

I've heard from several people about the 35i that exactly this is happening at the ignition switch.
"This could be something that happens more frequently with ignition systems in this generation."
works.

Hi, Jockel.