nuggie

89 jeep cherokee 4.0l auto trans 4x4

Okay so I got new plates for my jeep today drove it 100 ft no problems at all or so to my garage (closer to the tools) after swapping plates can't get it to start. Messed around for a bit and noticed that the aftermarket voltage gauge the needle is at (~)12.5 when in on position but when in start position the needle drops to 0 then when let go bounces right back up. The sudden loss of starter has me leaning to the nss. How do you check that? Haven't seen if the reverse lights work but I tried starting in both park and neutral and nothing. I was reading and the nss controls the ground to the starter(?), then what all controls the power going to the trigger wire? I haven't tried jumping over the starter yet I am ganna try that in the morning and thing else to test? I also watched on bleepinjeep about him cleaning his does that normal fix those, or do I gatta bust out another $200 for one

firehawk618

One way to kind of test the NSS is hold the key in the start position with one hand and slowly move the shifter through the gears. If you hear the starter engage at all while doing this then the chances are good the NSS is to blame.

You could always take a decent gauge jumper wire from the + post of the battery and touch it to the smaller wire on your starter solenoid to start your rig, or rule out the starter as bad.

You can also do this same thing with a strategically placed screwdriver on your starter between the positive post and the solenoid post.

*EDIT* I wanted to add the fact that your aftermarket gauge goes to 0 when you try to start is most likely meaningless. The person probably tapped into a wire that has no voltage when the ignition is in the start position.

The other thing you didn't mention is whether or not you lose power to EVERYTHING when you goto start. If so that is most likely crappy connections at the battery.

nuggie

Just tried it the lights on the dash work when attempting to crank tried moving the shifter while ting to crank and nothing

DFlintstone

Battery gasses have a nasty habit of helping a thin, hard crust form on the bat post's and clamps. They can look pretty good, but that micro-thin layer is a surprisingly good insulator. SHINNY! Lead is what you want. I use a pocket knife, (gently), for the insides of the clamps. For the posts I might use one of those post cleaner wire brushes, but still scrape it with a blade. If you have a condition where you have power, (dash lights ect.), then when you hit it power goes out altogether, that's a common result of a layer of oxidization there. Btw, a half *** connection could be expected to get hot during cranking, or while it's trying. Cleaning those is something to do now and then anyway, so if you are having starting problems, you might want to make sure you have bare lead on lead. Might save you some grief!


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The solonoid wire comes up to your starter relay by the battery. If you could click on the link in my sig, you would find this photo>

nuggie

Okay so I by passed the relay and I can get the starter to turn but I am getting a ground out of it so that means the nss is working right? The fuel pump will turn on but with the key no power is making it to that green wire

DFlintstone

I believe the Ign switch should power up that Ign terminal when starting, (yes, while the NSS grounds that ground.) Ign switch failure is more common then relay failure, I think.

There is an adjustment for the rod from the key down to the ign switch on-top of the column down there. More likely, the plug on the ign switch is melted, jacked up, then it suddenly being out of adjustment.

Have someone turn the key and see if it powers up that Ign terminal. Also look at, jiggle the plug on the switch and try it.

nuggie

so I checked and I do get power to the relay 5 volts in run 12 when in start. I by passed the relay and it work so I replaced the relay...same problem so I did a few more test I do have a ground until the relay is energized then the ground opens. So then I tested the reverse lights...nothing so I am thinking its back to the NSS. So does the NSS get a power supply from somewhere, it must right because it triggers the reverse lights? So I wonder if that getting power then activates the switch thus turning opening up the ground? where does it ground to maybe I don't have it grounded right. I have it "rigged" so I can start it now but I still wanna fix it right. I can confirm that my reverse lights did work the other day but no longer do. is there a fuse for it? I would love to try everything else before I throw new one on there I was thinking about taking it apart and trying to clean it does this normally work?

DFlintstone

O geez bud..I'm still working. (NSS adjustment for backup light aside), if the start relay is grounded by the NSS, and the key shoots 12V to the ign terminal, I think the relay should energize the solonoid. If you bypassed the relay you might toast your Ign stitch. Maybe try grounding the ground, then don't run over someone starting it in drive! (maybe the NSS does need cleaning, and is not grounding the new relay well, Idk....

Having 5V to that running might doesn't sound right. (there is 5v to lot's of sensors from the ECM, wires do chafe and short to each-other, so there's that.) Jiggling the wiring harness while metering things, sometimes reveals problem spots.

nuggie

Doesn't the starter relay also control the fuel pump what's that wire for then. It just doesn't sound right failing so suddenly. If I can fix it then I am ganna rig in a relay so the starter will only work when the brake is pushed... should be simple as long as that is one of the circuits that is shut off when the starter is triggered. Also I tried taking a look at the ignition switch is that the connector down on the steering Column with what looks like a metal rod going to it? I didn't see any burnt or melted wires beside a fuse to my blower motor that was melted in the fuse block. Any idea on where the nss grounds too?

nuggie

So you reccamend just grounding it out instead of by passing the relay? Makes sense I was kinda concerned that the 5 volts that was supplied would cause the starter to run when ever it was in run but aperently it isn't enough

nuggie

Ohh cool just notice I have a spare trans we pulled out of a junker jeep we had and it has a nss on it do they differ from year to year I think that one was a 90 or 91 it had the same motor and both are 4x4 don't know if the trans differ but it has the same connections

DFlintstone

I meant, ground the ground terminal on the relay. If that makes it work, then you know if the NSS wasn't grounding it well enough, and that everything else works. Just ignore the ballast resistor terminal. I'd guess it provides power for the fuel pump while cranking.

Starting, all the NSS does is ground the start relay. Cuz it's on the shifter, they also added separate stuff for it to turn on the reverse lights. Newer might be different...likely it's the same to 95...I don't know.

See if grounding the start relay works. If not, a new or cleaned NSS will not change anything.