Glow Plug Not Working: VW Passat 35i Fix

Hello!
Can you help me?
I'm having the following problem with my Passat 35i B4, 110 HP TDI, manufactured in October 1994...
After my engine swap, replacing the 1Z with an AFN, I still had a few...
Minor electrical issues. I have the efh's from the front, and the e-mirrors.
including the complete wiring harness throughout the car and the installation of the WFS system.
After that, my fuel gauge and interior lights started working again.
no sunroof (donor vehicle without sunroof).
After a long search, I discovered that a pipe is connected to...
Fuel sensor and a ground wire to the sunroof located elsewhere.
The fuse box was already there. I modified it as needed.
It was working the way it used to. Now, everything is working again.
The only problem that remains is the correct display of [something].
Water temperature (approximately 80 degrees Celsius) and a glowing preheating lamp.
It doesn't even light up when I check the temperature sensor in the engine compartment.
abziehe und dann Starte. Vorglühen funktioniert soweit. Only the.
The preheating lamp is constantly glowing, but this is only noticeable in the dark.
Can someone help me with this? Is something missing here?
Combination instrument or control unit?

[Translating...]

Kann mir da keiner einen Tipp geben was das sein könnte? Bin echt ratlos.
MFG

[Translating...]

Wenn du uns jetzt auch noch erzählst, aus welchem Fahrzeug (Typ+BJ) der AFN mit Kabelbaum kam sind wir schon ein Stück weiter. (AFN gab's im Passat Modeljahr 95 ja nicht).

Außerdem wäre wichtig, wo du den Kabelbaum überall getauscht hast. Innenraum hast du schon erzählt, aber was ist mit dem zum MSG? Oder dem zum KI?

Gruß
Guste

[Translating...]

Hallo!
Erstmal danke für deine schnelle antwort.
Also der Motor ist aus einem 96er Passat 35i Facelift B4. Motorkabelbaum wurde nicht gewechselt. Mir wurde gesagt das es der Gleiche ist. Bei VW im AKTE hat er auch die selbe Teilenummer.
MFG

[Translating...]

Hi,

leider habe ich für beide keinen genauen Stromlaufplan und kann dir daher nur grob helfen.

Beim ML95 Passat TDI soll die Vorglühleitung vom KI Pin 20 über gn/ws über Steckkontakt auf bl/gn bis zum Motorsteuergerät Pin 48. Das Signal ist Masse geschaltet. Wenn die Lampe an ist solltest du gegen Masse also ca 0V messen, wenn die Lampe aus ist solltest du auf der Leitung also etwa 12V messen.

Beim Ende 96er AFN läufts aus dem KI aus Pin 13 über br/gn bis zum MSG Pin48.

Die Schlatlogik ist identisch geblieben, nur die Pinbelegung des KI hat sich geändert.

Wenn du aber das alte KI + Verkabelung drin gelassen hast und nur das MSG getauscht hast, sollte es eigentlich gehen. Also hilft nur ein: MSG pin48 gegen KI pin 20 durchmessen.

Gruß
Guste

[Translating...]

Hallo!
Sorry das ich mich erst jetzt melde. War viel Unterwegs. Ja erstmal vielen Dank soweit. Werde dem mal nachgehen. Werde euch auf jeden Fall dann berichten ob es Läuft.
MFG

[Translating...]

Hallo!
Also ich habe das mal durchgemessen.
Wenn ich den Pin 20 vom KI an masse halte leuchtet die Vorglühleuchte.
Dann habe ich mal den Pin 13 vom KI an Kontakt Pin 20 gehalten.
Dann blitzt die LED nur eimal kurz auf.
Kann mir jemand sagen wie ich die Vorglüh LED wieder zum leuchten bringe während des Vorglühvorganges?
Es ist gerade im Winter doch ein Vorteil, wenn ich sehen kann wie lange er Vorglüht.
Wenn mir da jemand weiter helfen könnte währe ich sehr dankbar.
MFG und schon mal danke im vorraus.

[Translating...]

Hallo ich hatte das gleiche problem da sind 2 adern verdreht vom 1z zu afn am steuergerätestecker Vorglühlampe und heizung Kühlwasser leider weiss ich die pins nicht mehr aber wenn du die noch unbedingt brauchst bekomme ich das noch raus. ausserdem habe ich über die led einen 1k wiederstand gelötet weil das glimmen immer noch nicht weg war.

[Translating...]

Hallo!
Also ich fahre schon die ganze zeit mit Glimmender Vorglühleuchte.
Man gewöhnt sich an alles. Also wenn du da was genaueres weißt,
würde ich mich freuen dieses Problem beseitigen zu können.
MFG

Okay, I checked, and you need to swap pin 48 (blue/green) with pin 26 (black/brown) directly at the MSTG connector. One of those wires goes to the light bulb, and the other comes from the auxiliary heater relay on the splash guard. After that, the light bulb should work, but it will still glow dimly. Then, I added a 1 k ohm resistor in parallel with the light bulb (I soldered in an LED), and now it doesn't glow at all.

I cannot guarantee that this will be the case for you.

I converted my fuel injector from part number 1Z 028906021B to part number 028906021DF, which is compatible with a Golf 3 MSTG AFN engine.

Hello!
I tried it right away. And now the light is working.
Thank you for the tip. Regarding the 1kOhm resistor...
I will also do that. The child will have to do it anyway.
Reflow the solder joints due to the likely presence of dead solder joints.
Thank you again.

Good day, esteemed forum members,

I have a similar problem. But I don't have a solution yet, maybe you can help me.

Background:

The base vehicle is a Passat 35i B3, manufactured in 1992, with a 1.9 TD AAZ engine.

I recently had the opportunity to buy a donor car at a very good price. It's a Volkswagen Passat B4 1.9 TDI AFN, manufactured in 1996, with full equipment including electric seats, heated seats, cruise control, electric windows, climate control, central locking, and ABS.

This donor unit was missing the alternator, starter motor, and key.

Ich habe das Steuergerät weggebracht und die Wegfahrsperre deaktivieren lassen. The engine is running.

After that, I installed everything, including the central locking system and Climatronic, into the B3. It runs, drives, and brakes. I didn't install the airbag. I took it for a first, longer test drive, and during that, the electronic diesel MFA speedometer from Motometer almost melted.

I haven't found any obvious errors yet. I haven't tested the power windows and central locking system yet.

I've acquired another speedometer. However, this speedometer now exhibits the glow plug indicator light flickering, but it also shows the normal preheating indicator.

Have I forgotten to assemble something that could have caused the Tachobrand incident? I need your help to move forward.

Thank you very much.

Hello,

If the new instrument cluster doesn't have a traditional preheating lamp (incandescent bulb) but instead uses an orange LED, the problem might be that a minimal amount of current (a test current for incandescent filaments?) doesn't activate a traditional bulb at all, but it's enough to cause the LED to light up slightly.

To fix the issue, as mentioned above (I've corrected the value), add a 1 kOhm (1000 Ohm) resistor in parallel with the LED connection. Just check the wiring diagram to see how the wire from the ECU is connected, either to ground or to +12V.

The 0.25W power rating of the resistor should be sufficient. Everyone is happy because the control unit now sees a "glow plug test current," and the LED no longer flickers because the test current is flowing through the resistor instead of the LED.

Best regards, Rainer.

Hello Rainer,

Thank you for the quick response.

Do you have any idea why the speedometer was reading so high? Was it a fault in the speedometer itself, or was the problem caused by the ZE (likely referring to an electronic control unit)? The ZAS (likely referring to a sensor or module) is also new.

Passat35iAAZ wrote:

Hello Rainer, Thank you for the quick response. Do you have any idea why the speedometer was almost maxed out? Was it a fault in the speedometer itself, or did the error originate from the ZE (control unit)? The ZAS (sensor) is also new.

Incorrectly connected, or is the wiring slightly different?

That's exactly what my problem is.

"Does anyone have a wiring diagram for a 96 AFN for the instrument cluster, engine, and Climatronic with Econ? I'm not sure if the components are working correctly or if the wiring is wrong. The cruise control isn't working either, and the ABS is also showing an implausible error message. Also, relay 109 is getting very hot (I've already opened it, and it looks fine), and I can't access the MSG."