Another Jeep Won't Turn Over Thread

[dirtslinger1]

Yesterday, drove to dinner in the TJ, went out and it wouldn't turn over.

I have an 01 TJ 4.0 Automatic.

So far,
1. I have swapped relays around to see if it was a relay, no change.
2. Checked fuses under the hood, no change
3. Replaced ignition actuator, wasn't broken, and no change
4. Replaced Ignition switch, no change
5. Checked for voltage at starter solenoid wire, no volts when turned to "start"
6. Jumped across starter solenoid and hot, and the starter turns over

I'm totally stumped and really don't want to take it to a mechanic.

 

[Noxid]

Have you checked your battery? KISS principle first. Will it start if you jump it?

 

[dirtslinger1]

Battery voltage is good, when I jump across the actual starter solenoid to with a screw driver, the starter turns over, it's not getting 12volts to the starter when the key is switched to start, and I have tried all of the above things.

 

[JSpike]

Try turning key to on position then jump starter solenoid and see if it will start ? Get back with us on that

 

[dirtslinger1]

Try turning key to on position then jump starter solenoid and see if it will start ? Get back with us on that

Yes, the Jeep will start if in the ON position and I jump the starter solenoid with a jumper wire

 

[dirtslinger1]

I've also tried shifting into to neutral and jiggling the shifter while trying to start, something is NOT allowing 12v to the starter solenoid

 

[hear]

Not even cranking sure feels NSS related. I might try to turn the key while somebody underneath jiggles the harness from the NSS up over the trans housing. Seems like every jeep I touch ends up having some sort of short in the harness in that general area. And it wouldn’t be the first time everything was ok and then suddenly it wasn’t, and it turned out to be wiring.

That it will run if you jump the starter proves it’s not a run condition problem like no spark or no fuel. Off the top of my head I can’t think of any other circuits that would prevent it from turning over, other than the starter/ignition wires themselves.

 

[dirtslinger1]

Not even cranking sure feels NSS related. I might try to turn the key while somebody underneath jiggles the harness from the NSS up over the trans housing. Seems like every jeep I touch ends up having some sort of short in the harness in that general area. And it wouldn’t be the first time everything was ok and then suddenly it wasn’t, and it turned out to be wiring.

That it will run if you jump the starter proves it’s not a run condition problem like no spark or no fuel. Off the top of my head I can’t think of any other circuits that would prevent it from turning over, other than the starter/ignition wires themselves.

The NSS is the last thing I can think of, I tried to crawl under the jeep, but I can't see anything with the exhaust and skid plate in the way.

Do I need to drop that skid and or something else to get to it?

FYI, I have the 3 speed auto, no overdrive.

 

[hear]

I don't think you need to drop the skid to get to the nss, but it is sort of behind the front driveshaft-ish. The wiring goes up over the trans, so it's just generally a pain.

I'm not saying this *is* your issue, but I'm a huge fan of unplugging everything under neath and pulling the entire harness up into the engine bay. Take off all the brittle old loom & tape, and inspect everything. I would not be surprised if you were surprised by the condition of the wiring in there. There are a few known trouble spot where the harness rubs on a valve cover post, but I seem to find more issues a little further back for some reason.

The benefits of doing this job are (a) you will KNOW you have clean wiring, so you'll either fix your issue or eliminate a potential cause and (b) you'll replace it with fresh tape & loom which will make it easier to work on in the future. The loom that's in there now will literally disintegrate in your hands. But I also get why you might not want to do all that w/o knowing you've got a wiring issue in that area.

Maybe start by tracing the wires from the ignition to the starter to see at what point things break down. The wiring is REALLY complicated under the dash where it goes through the firewall (I'm pretty sure that's where the ignition wiring goes). It's a little easier if you follow the wiring diagrams in section 8W of the FSM. We're here to help you troubleshoot though.

Here is the link to the 2001 FSM: https://wranglertjforum.com/threads...ice-manuals-fsm-technical-documentation.4618/

 

[NskLJ]

The NSS is the last thing I can think of, I tried to crawl under the jeep, but I can't see anything with the exhaust and skid plate in the way.

Do I need to drop that skid and or something else to get to it?

FYI, I have the 3 speed auto, no overdrive.

Check the fuse 6 in the under hood fuse box it should have power all the time.
Check fuse 20 in the glove box should be hot while cranking.
If both those are good go to the neutral safety switch.
Disconnect and jump the brown/light blue wire to ground and test, if it cranks now replace the neutral safety switch. It is a 3 pin connector and the wire will be the center pin.

 

[hear]

Good call on the fuses. I’m inclined to believe it’s the wiring rather than the switch, but jumping the pigtail will isolate that and you’ll know either way.

 

[dirtslinger1]

I gotta head back home, so I'll get to these fuses and the NSS in a couple week. I'll report back.

 

[dirtslinger1]

One quick update, when I started it to move it into the garage, it had a Check Engine and an ABS light on. Neither of those were on before it decided to not start. Guess I'll grab a code reader when I head back out to check out the NSS.

 

[Noxid]

One quick update, when I started it to move it into the garage, it had a Check Engine and an ABS light on. Neither of those were on before it decided to not start. Guess I'll grab a code reader when I head back out to check out the NSS.

I truly suspect its your battery. Pull it and take it to be tested and or buy a new one and swap it out. You can always return the purchase if it ends up NOT being the battery.

 

[Mitchrb1]

I have the 32rh auto also. I had a similar issue with the cable putting it fully in Park. I could start the Jeep in Neutral when that happened but, not while in Park. The cable had come lose from the Bracket that holds it. Snapped it back in and put a zip tie in to keep it from popping back out.

 

[dirtslinger1]

I truly suspect its your battery. Pull it and take it to be tested and or buy a new one and swap it out. You can always return the purchase if it ends up NOT being the battery.

I haven't load checked the battery, but when I test the wire to the solenoid, I'm not getting 12v when the ignition is turned to "start", I can also jump the solenoid with a 12v source and it starts just fine, which leads me to believe the battery is just fine.

Also when turned to "start", I get no change in the battery voltage.

 

[dirtslinger1]

I have the 32rh auto also. I had a similar issue with the cable putting it fully in Park. I could start the Jeep in Neutral when that happened but, not while in Park. The cable had come lose from the Bracket that holds it. Snapped it back in and put a zip tie in to keep it from popping back out.

I cannot start it in Neutral or even while jiggling the shifter, nor any combination of shift positions.

 

[Jerry Bransford]

I haven't load checked the battery, but when I test the wire to the solenoid, I'm not getting 12v when the ignition is turned to "start", I can also jump the solenoid with a 12v source and it starts just fine, which leads me to believe the battery is just fine.

Also when turned to "start", I get no change in the battery voltage.

Your battery is fine. I'm leaning towards the NSS or its wiring too. Note the NSS has 3 wires going to it.

 

[dirtslinger1]

Your battery is fine. I'm leaning towards the NSS or its wiring too. Note the NSS has 3 wires going to it.

View attachment 389190

Thanks for that picture Jerry, whats the best way to get to this thing? I couldn't even locate it when I looked under there, LOL. Seems like a cheap part, and if I can get to it, not a hard job to replace, so when I head back out to my vacation place, I'm just going to bring one with me.

Would a wiring issue or NSS, cause a check engine light? I never had that or the ABS light until I had this issue, or started checking fuses and relays.

Also, when looking into my engine compartment, which harness should I be focusing on? My jeep is completely unmolested.

 

[Jerry Bransford]

I can't think of any reason a bad NSS switch could cause a CEL. The wiring harness for the NSS and torque converter lockup (at the very rear of the transmission) connectors drops down from the top of the transmission tunnel.