Last week we went out to start our forklift and it wouldn't turn over. We did the obvious things, hooked up jumper cables from our big diesel truck, took out the starter and had it tested, and replaced the starter relay. But it still won't turn over. When we turn the key, we can get a clicking from what sounds like under the dash, but that's all. Not only that, but it has recently started making the clicking sound on it's own, with the key in the off position. Any help would be great. Thanks.

-Dave