Hi all Jungheinrich Experts,
My Jungheinrich truck model ETV214-2008 has problem as: after turning ON the Key SW, the display 3U7 only show the working hour meter without any else information - the main contactor K1 doesn't close. I have checked all the fuses are OK; have tried to make the bypass for the power contactor 1K7 but the main K1 couldn't be ON; change the new full charged battery but the problem is still the same.

I have tried to replace the display Julia 3U7 and MFC travel and brake 1U23 by the new ones taken from the good truck but the problem is still the same.

Due to the display does not show any error messages and any else support information so it is very hard for me to find the way how to check.
I'd be gratefull to you very much if you could please give me some advise how to solve this problem.

Thanks in advance & Regards