Heavy Equipment Forums Heavy Equipment Community

Wacker ST45 Won’t Start – HELP?

exekia ยท 2026-09-22 08:59

Hi - I have a 2015 or 2016 Wacker ST45 (Perkins model). Has been a reliable workhorse. 1700 Hrs. New Battery. A couple of days ago, went to start it - key wouldn't move past "ON" - couldn't get to the spring part to start. Didn't think anything of it, flipped the key around, couple of more tries and starts. Turned it off (at temp) about 20 minutes later to change attachments. Won't start. No codes. Took battery out and charged it. No go. Relay clicks (behind the seat). Changed it anyhow. Starter fuse behind seat is ok, changed it anyhow. Mega fuses in engine compartment above battery are ok. Cables on back of starter are tight and look ok. Didn't disconnect or clean and reconnect but seemed ok. Ground to engine looks ok. Not sure where to go next. Could it be lap bar safety switch? Why does relay click then? Could it be the ignition switch itself? Same question about relay clicking. Pics and video attached. Thanks in advance!

Replies4
  1. #1Simon C2026-09-22 09:52

    Does the key turn over to the "S" Terminal spot, furthest right or not. If it doesn't, don't expect any cranking. Position just before "S" Terminal of key is usually IGN or ACC, cant remember exactly, but will put relays on and dash and other things as well. Simon C

  2. #2exekia2026-09-22 10:35

    It does get to the "S" (spring loaded part to start). Sometimes, however, it will not let me get there. Then I go back to off and it lets me get to S again.

  3. #3Simon C2026-09-22 14:30

    Need to have someone hold the key in the start position while you check the small "S" terminal on the starter Solenoid to see if there is power there. If there is no power there than start at Key switch to see if there is Power at the back side of key at Key "S" terminal. If no power at key is there power at the Key "Battery Terminal". Assuming you tested all fuses with test light not a multimeter. Even the smallest path will give full voltage on a multimeter. Start somewhere. Simon C

  4. #4HarleyHappy2026-09-23 10:11

    Sounds like you need a new ignition switch. Try and oil up the key.