Why is the first boom section on my Liebherr LTM 1400 not unlocking even though the solenoid valve is working?

[Emmanuel M.]

I'm having an issue with my Liebherr LTM 1400 (1998 model) and hoping someone here has dealt with this before. The first boom section will not unlock. I already checked the solenoid valve, and it seems to be working fine, but I'm missing power on wire No. 110. So far:

• Solenoid valve tested okay
• Boom still won't unlock
• No power reaching wire 110

I'm trying to figure out where to look next before I start tearing deeper into the electrical system. Could this be a relay issue?

 

[Felipe Rances]

If the solenoid is working but wire 110 has no power, I'd definitely start chasing the electrical side before digging into the hydraulics. A bad relay, limit switch, corroded connector, or even a broken wire somewhere in the boom harness could be the culprit.. sometimes it's the simplest electrical fault that causes the biggest headache.

 

[James R.]

No power on wire 110 definitely sounds like an electrical issue. I'd check the relay, wiring, and any limit switches before digging any deeper.