GRA Outlet Box Kl15a - Disconnect Switch

Hello,

I installed a GRA (Gas Recirculation Valve) in my 1Z engine.
Unfortunately, the GPU occasionally experiences glitches, which means:
GRA active, speed set --> then suddenly it turns off, and even resetting doesn't work.
So, the stored value is gone.
The interruptions sometimes occur unexpectedly, and other times when another consumer, such as the electric heater or windshield wipers, is in use.

My assumption is that, according to the Single Line Protection (SLP) documentation, the power supply should be provided via circuit breaker Kl15a.
Since I couldn't find a suitable connection, I connected it to terminal block Kl15.
Is that where the error lies?
What is KL15a?
Okay: Part number 028 906 021C.

Right off the bat: It's not the clutch or brake pedal sensors, because if it were, the value would remain in the memory.

Thank you in advance for your help.

Regards,
Okay, here's the translation:

"Nick"

The GRA (presumably a device) not only has the set button, resume button, clutch switch, and brake switch, but also the power on/off switch itself. The latter would also explain your symptoms.

Therefore, simply wire both inputs of the Message Signal Generator (MSG) directly to "ON" to reliably disable the switch.

Best 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."

Thank you for the tip.
I've already tried that. I shorted the switches, but I still have the same problem.
I couldn't detect any instability or other contact problems.
The X-relay has also been checked.


I was more inclined to suspect that the power supply might be coming directly from the MSG (Main System Ground), specifically terminal KL15a, in order to rule out potential differences caused by other consumers.

Regards,
Okay, here's the translation:

"Nick"

Unfortunately, you didn't specify which vehicle this refers to. Based on the "1Z" designation, I'm guessing it's a Volkswagen Golf 3. According to the wiring diagram (SLP), terminal 15A is essentially the same as terminal 15, but protected by fuse 14. The reverse lights are also connected to this terminal.

Therefore, there shouldn't be any difference compared to class 15.

If you want to rule out interference and have some basic knowledge of electronics, you can add an LC or RC damping element to the power supply line. (In the simplest case: a capacitor, approximately 100 nF, connected in parallel between the GRA input signal (pin 66) and the measurement ground (e.g., pin 46). Then, connect a resistor in series between the switch and pin 66/capacitor. For example, 100 ohms, or even 1 kOhm.)

I suspect other issues are more likely, such as a loose connection in your wiring. Where did you bypass the switch? Directly at the switch itself or at the MSG (Main System Module)? If it's the former, first disconnect the connection between MSG pin 66 and the switch, and then bridge MSG pin 66 and pin 68. This will allow you to safely rule out any wiring problems.

Or do you perhaps have other unauthorized devices installed that are completely messing up your car's electrical system? (I once had cheap xenon retrofit kits in my Golf 3, and they caused all sorts of problems...)

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."

Ah, now I've found it too...

It is located on pin D11 of the ZE box.
I need to check again where I put it.
But as you already wrote, they are actually just ordinary KL15 models.

Hmm, well, I've already added quite a few optional extras.
The vehicle is a Caddy 14D with engine code 1Z. However, I've done the electrical work very carefully and mostly used genuine parts. All wiring harnesses are new and from models G3 or G2.
eFH (G2); eASP (G2); SHz (G2); GRA (G3); MFA (G3); ZV (Accessories);...

I'm going to investigate potential contact issues again.

Let me know if you need anything.
Thank you again...