Finding the Autocheck Relay for headlamps

[HenryG40]

Hi guys,

Although I've searched the forum for the autocheck relay as I've just fitted a HID kit, I'm having problems finding the Autocheck relay in my S4. I've found the relays in the box in the engine bay on the drivers side, and one or two relays under the steering wheel, I'm yet to find the Autocheck relay I'm after!

Where am I going wrong! I Understand what I need to do once I find the damn thing.

Here are some pictures of the relays I've found so far:






Cheers
Henry

[Fat Audi 80]

Don't know!

You should be looking for relay 305 as per post 13 on this thread. (But I guess you know that already...)

http://www.s2forum.com/forum/showthread.php?t=2947&highlight=Autocheck+mod

Cheers,

Steve.

[S2central.net]

It might be numbered differently... IIWU - turn on your side lights with the key out of the ignition and open the drivers door - you should get a warning buzzer. Remove relays ONE BY ONE until the buzzing stops - that will be the relay you want !

Hopefully you will find it b4 the battery goes flat !


Paul

[HenryG40]

I'm assuming the relay should be in the box within the engine bay? There are two relays in there marked with the 'Hella' logo but have no effect on the buzzer. According to link posted above, it should be a double sized relay in the S4, but the pins appear to have a different layout to the relay shown in the images.

Trust me to make a pigs ear of one of the easiest modifications!

[S2central.net]

Actually I might be talking arseflaps on this one... The buzzer unit may be different than the bulb monitoring relay. I can look it up on Bentley if you like (for S4/S6).

Paul

[HenryG40]

If you could look that up Paul, it would be much appreciated. I am saving my pennies for the Bentley manual. I can generally work my way around a whole mk1,2,3 polo without too much bother but it's proving to be quite difficult to do the same on the Audi!

[S2central.net]

Dangit - knew I shoulda bought the paper version - I have this particular manual on CD-ROM and its a PITA to run with MacOSX so be patient if you can !

Paul

[S2central.net]

Burger it - I'll have to dig out the old trusty Win95 machine to access that Bentley CD. Later dudes !

Paul

[80Quattro]

It's the hella one with 301 on the top, it covers the headlights rear lights and brake lights not like the S2 one where there is a separate headlight one.

[S2central.net]

Yep - found it on the Bentley CD for 100-S4. Its referred to as the Lamp COntrol Module (J124) and is shown as a double wide module in positions 14 and 15 on the auxiliary relay carrier... NOT the one at the fusebox.

[S2central.net]

The mod on the S2 is to remove the K-wire from the front lamp control module (J123 which is marked 281 on the relay body)...

The same logic on the S4 with relay 301 should apply, but because the S4 uses a single controller for front and rear there are actually two K-pins notated 'KS' and 'KB'

Following the logic from S2 wiring that shows 'KS' for the rear lights then I'd go for pin 'KB' on the S4's 301 module. That is pin 3 on the module, but if that doesn't work then go for pin 9 which is 'KS'... Just remove the control unit and carefully bend the unwanted K pin over 90 degrees so it doesn't raise an alarm to the autocheck module. Make sure it doesn't touch other pins on the 301 module.

If there isn't enough room to bend the pin over without interfeing with other pins, then don't cut it off. Instead, remove the wire it connects to in the relay pod. KS is a grey wire and KB is red.

To summary - try pin 3 (KB) first - or its red wire
If that doesn't eliminate the HID triggered warning then go for pin 9 (KS) - grey wire

HTH,

Paul

[HenryG40]

Can't thank you enough for the help, will give that a go in the morning. The irony is that after trying to find the relay and work out how to disable the autocheck for the headlamps, the brake pad wear indicator is now coming up on the autocheck! Ideal considering that I'm driving to lands end tommorow from Cambridge

It appears that EBC Red stuff pads are the common choice, and they come in at around 100 pounds it seems! The joy of buying a new car

Cheers again, will let you know which pin saves the day!

[S2central.net]

Actually the EBC reds are no great shakes really... Ferodo, Textar or Pagid are better pads in my view. Search the forum for this subject and please do let me know which pin it is for the HID mod thang.

Paul

[80Quattro]

I'm going to guess and say it's terminal KS as the grey wire is the colour the S2 uses for the headlight and tail light warning. Also the red wire does appear to go to the brake light warning lamp on the current flow diagrams for the C4 A6. There is no easy way to tell even though I have the relay in question in front of me.

However, I would not suggest bending either the KS or KB pin as you will loose your tail light warning as well as the headlight one (saying that if not having a tail light warning doesn't bother you then go ahead and bend the pin). I would suggest you follow the link in post 2 of this topic and modify your relay as shown in post 8.