My Jeep won't crank over!

I seem to be having an issue with my '98 Cherokee, in that it won't even crank over when I turn the key to the START position. Everything else works just fine. When I turn the key, the relays in the underhood fuse box click, as well as a relay inside the passenger-side kick panel. There is no clicking from the starter solenoid. I've swapped the relays out with other ones and the problem remains, so I don't really think it's related to that. It can be started if the key is turned to ON and I jump the starter solenoid with a screwdriver. Still, this is an intermittent problem.

Now, I bought this Jeep as a totaled vehicle (front-end collision). It's basically road-worthy now, but I've heard stories that important wires tend to be severed in a front-end Cherokee collision, rendering the vehicle unstartable. I looked when I put everything back together and I didn't find any broken wires, and the only wires that traverse the front bumper are part of the headlight harness, anyway.

I'm currently thinking that it's either a problem with the neutral safety switch or the crankshaft position sensor. If it were the CPS, though, I think that I would experience some engine issues -- it idles just fine when it does run (I haven't actually driven it yet). Is there anything else that I should check?

The CPS doesn't affect cranking ... only firing. A vehicle with a bad CPS will sit there and crank all day.

Have you tried starting in neutral rather than park?

My guess would be the Neutral Safety Switch. Then after that i'd check the starter. Check out this link, it tells you how to repair the NSS. As soon as i did this, it fired right up.

Check your battery cable to the starter.

Thanks for the insight, guys. I didn't know that about the CPS, so I can rule that one out. It didn't crank when I tried starting in neutral.

I was able to start it last night and pulled it forward about three feet (read: moving the shifter) before I realized I forgot to add power steering fluid. I put it in park, turned the engine off, and it hasn't started since then. That sorta leads me to believe it's a neutral safety switch-related problem. Thanks for the link, MudslinginXJ, I'll have to try that. It's certainly better than spending $250 for a new switch!

I will check the battery cable more thoroughly than I did last night. It still looks fairly new, though.

Have you tried turning the key with one hand while jiggling the shifter with the other? Last ywear I was at a gas station and a young lady with a brand new TJ Wrangler was wandering around looking for someone with jumper cables. Her Jeep was at the pump and wouldn't start. Once I saw how new it was, I just hopped in and jiggled the handle ... it fired right up.

I also think that it is the NSS. When I put in my rebuilt tranny and tranfer case I had the same problem when I went to start it. Only by jumping the starter that it would start. Switched switches and problem solved.

Well, it turns out the neutral safety switch was the problem -- though for a rather unusual reason.

When I took everything apart, I found the wiper arm CRACKED and in two pieces. How this happened I have absolutely no idea, since there's no stress whatsoever on the arm. I was going to try JB Welding it back together, but I'm afraid that it would break again at an inopportune time (really though, when is a good time?).

Instead of shelling out $267 for a new switch, I'm going to try the junkyard. Hopefully they won't know how much it really costs . Did the Aisin AW4 come in any vehicles besides Jeeps?