Electrical issue

[Gazelle05]

Replaced dead starter batteries. Went to start engine turn on ignition key , dash lights up , low air alarm sounds for about 30 seconds then all goes quiet. Nothing happens when try to start, dash goes dead. Any ideas as to where I should begin to solve issue.
2005 Safari, Cat 400. Thanks

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[Artum_Snowbird]

Take your jumper cable and connect from the battery negative to a very solid ground on the engine. If everything works as it should, keep looking at the ground connection from the battery to the frame until you find the problem.

If that does not help at all, follow the positive lead, even running a single jumper cable from the positive battery to the starter to see if that fixes it.

It's most often the negative not hitting ground, but I have been both ways. Once you do this test you eliminate half of the possibilities.