T4 horn failure

Hello,

I'm currently experiencing a very unusual problem with our T4. The original signal horn (both horns) failed, so I replaced it with a universal kit from Hella. To do this, I cut off the VW connector and crimped on standard 6.3mm connectors. So far, so good. After a year, the contacts on both Hella horns had corroded, and they were replaced under warranty. However, I recently bought a set of OEM horns, or horns with OEM-style connectors from VW, online. I crimped on the connectors again and installed the horns.

Previously, the horns had been out of order for weeks due to the severed cables.


Okay, here's the problem: When I turn the ignition on, the horn sounds (it "beeps"). However, when I start the engine, I can honk the horn as much as I want, but there's no sound anymore.

In my opinion, the problem likely isn't with the horn itself or the wiring, since power is reaching the front of the car. What I haven't measured yet is whether power is actually reaching the horn when the engine is running.

Since the entire problem seems to be voltage-dependent, it must be due to the relay, as that's the only component that is sensitive to voltage due to the coil.

Or do you have any other ideas?


Circuit diagram: http://t4-wiki.de/wiki/index.php?title=Datei:Elektrik_Hupe_Schaltbild_Hupe_zweifach.jpg&filetimestamp=20080315162059

Hi,
What are the voltage levels at the relay for the horn (control and power supply) and at the button when the ignition is on and when the engine is running?
Does the wiring diagram match your T4, or is it complete? The background is that one of the circuits might only be connected to ground via a bridge that is not shown in the diagram.
Okay, I understand. Please provide the German text you would like me to translate into English. I will only provide the translation.
Herbert.

Hello Herbert,

I still need to test everything, but I didn't have a multimeter with me yesterday. I've found that I can easily swap out the relays; the turn signal relay and the horn relay are probably the same.

Okay, I'll check if the relay's ground connection is properly established through the steering wheel contact, and verify that there are 12V at the relay itself when the engine is running. I'll also measure the voltage at the horn connector.

It's quite peculiar that the running engine prevents the horn from working...


Circuit diagram matches; 3 pieces available from the bus.

Vehicle series TRANSPORTER with single-tone horn, no relay.
Vehicle series CARAVELLE / MULTIVAN with dual-tone horn and relay control.
Vehicle series CARAVELLE / MULTIVAN with dual-tone horn and relay control, vehicles equipped with ESP.

Ours is the second one, so it's the double-tone version without ESP.

Please provide the text you would like me to translate from German to English.
Measure from the body to the steering column!

Common mistake when horns are not working.
Since the steering column is mounted on rubber bushings, it requires a separate ground connection. In many vehicles, this connection is often located in a way that makes it prone to corrosion over time.

Okay, good tip!

But how does that relate to the engine's performance?

I haven't had a chance to check the wiring yet. However, another issue I'm experiencing is that the windshield washer system sometimes stops working. I don't understand this at all. The horn has a connection to the ignition power and receives its ground connection through a relay. As far as I know, the windshield cleaning system also has a ground connection, and it's connected to the pump, which is grounded near the reservoir. It also receives ignition power through a relay.It sprays for 1-2 seconds, then stops, and then doesn't work again. There's some kind of strange electrical issue with the car.

Okay,

The problem persists. The wiring seems to be okay. When you turn the steering wheel, the horn sounds... I suspect the slip ring is the issue.


Can it be cleaned? I hope it's the metal tab for the grounding contact... because the slip ring for vehicles with airbags/facelift is really "expensive."

Does the spare part number 7D0959653 fit a T4 manufactured in 2/1999 with the facelift features, such as blue lighting and a longer front section?

It's all very similar technology to that found in the Golf 3.

To my knowledge, it still had the conventional contact point for the horn, despite having an airbag.

The suspension was easy to see and clean - otherwise, it just gets clogged with dirt and stops working, or it starts to make a scratching noise when you steer (like it did for me).

A bus is supposed to have a http://www.aibas.de/assets/images/BigBlast_III.jpg.

m;

Okay, I was thinking about trying to lower it a bit, lowering the steering wheel, cleaning the contact terminals, applying a little battery pole grease, bending the terminals slightly, and hoping .

Or, alternatively, just let everything sit and then pull through a soft, fluffy cloth.

Regarding the horn connectors that corrode: If the connector is energized with a positive terminal and activated via a switched ground, then my keyword is "electrochemical corrosion". This can be prevented in mass production by using sealed connectors, thus keeping moisture away, or in aftermarket horns with unsealed flat connectors, by mounting them with a generous application of pole grease preservative. However, this also doesn't last forever and will eventually need to be renewed.

Quote:

mit satter Polfettkonservierung.

Regarding the T4?
Where is that thing located, in the constant path of the front tire?

I would recommend moving the plant to a drier location first.
Furthermore, when installing a long 5th gear, you won't hit your head on the horn and its steel bracket .

m;

It even had a "shield" or "guard," didn't it? But you're right, you could also attach it somewhere else.

Hutfahrer wrote:

Didn't that thing even have a "shield" or "cover"?

Yes, it did.

But the original equipment has sealed connectors, right? At least those should be tight...

Okay, so the replica horns with the printed VW number from eBay, which come with original connectors, are leak-proof.

The error has also been found... don't ask what the steering wheel slip ring looked like; it was completely crumbled, including the coil spring.

I'm not surprised the airbag light hasn't come on yet.