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CAT 420D Not Starting – Electrical Issue?

CATinLiberia ยท 2021-06-07 18:35

After a couple years of not running, I am doing some repairs to my CAT 420D to get it back into regular use. Unfortunately, I cant get the engine started. When I turn the key, all that happens is the electric pump kicks on. The starter is totally silent. The battery is charged, the cables have good contact, fuses are all good, the frame is well grounded, the direction control switch is in neutral and the hand brake is engaged. When I turn the key on, the alarm starts beeping and the normal lights come on, but nothing from the starter. Like I said, when I turn the key to engage the starter, all that happens is the electric pump kicks on. Last time I ran it, no issues starting. I.ve never had this problem before. One strange observation: the digital hour meter is blank. Any advice for troubleshooting?

Replies6
  1. #1CATinLiberia2021-06-09 14:09

    I'm bumping this to see if anyone has any advice. Thanks!

  2. #2heymccall2021-06-09 14:58

    Can you put test light on starter trigger terminal and verify 12v when in crank?

  3. #3heymccall2021-06-09 16:33

    http://www.catsch.info/renr3587.html Is link to schematic.

  4. #4CATinLiberia2021-06-10 11:11

    Good thought. I assume that's the single wire/terminal on the lower front of the starter. I tried a positive jumper wire to it from the battery, but the only result was the electric pump kicking on. Nothing from the starter. I'll check with my multimeter. Thanks! If I have 12v when attempting to crank, I assume that means I need to pull the starter and check for internal issues... maybe the solenoid or brushes?

  5. #5CATinLiberia2021-06-10 11:11

    Great! Thanks!

  6. #6CATinLiberia2021-07-12 16:20

    Yes, juice is there. I ended up pulling the starter. Two of the four brushes were shot, so I changed them and cleaned everything else up before reassembly. After two years, it fired up immediately! Thanks for the advice!