Hello, I cannot find a very nice thread with repair guide of G25 H-pattern malfunction when in 4th or 6th gear.

It's a known problem with electric pots/paths wear out. When you put 4th gear in, it send 2nd gear signal after few secs. Same is with 6th>4th gear.

There was a great topic with pics, how to repair this thing but I can't find it anymore

I found the thread but all of this pics no longer work. Here's a YouTube video of how to disassemble the shifter:
http://youtu.be/dJeBq6kqAnU

From all the posts I read on various forums, the most likely cause is loose or broken wires due to PCB (printed circuit board) movement. The common solution was to replace or resolder the thin wires.

For images, search Google Images for "g25 shifter repair' - there are many images there that may be useful to you.

Hope this helps.

Thanks Gunn. I found first evildoer - red cable is broken.
I have to wait for my soldering iron till friday and hope this fix will help.

sounds like the loose potentiometer problem (that i'm having again )

you can see in post #22 here:
http://www.simracers4life.com/index.php?topic=787.15

fix is to glue something somewhere so there is no wiggle in the potentiometer that detects left-right.

Thanks for tips guys. Fixed red wire and it's all ok now.

Potentiometer on the right side was loose by 1-2mm but it doesn't cause any problems yet.