tj40

jump the harness at the firewall just unplug the whole harness that goes to the trans. CAREFUL there are two rectangle shaped plugs that go to the trans. You will need to trace it up the plug that you want comes from the pass. side of the jeep. the connection is at the trans dipstick tube area, well they both are. On my jeep the nss harness is black and the other harness connector that you can leave alone is white. but don't go by that cause years change, you can unplug the harness jump the plug at the engine. The other end can just dangle it will be fine I ran around without the n.s.s. for years (without reverse lights) without driving issues.

tommyis3

OK, I doing the jump in the engine bay, to the black plug B+C contacs to the end that goes to the transmission.

93XJRay

im going to jump the solenoid on mine right now. when i get back from the coffee run im going to bypass the nss and see if i have any luck.

tj40

the jump needs to be made where it goes into the computer harness not the lead going into the n.s.s. I knew my n.s.s was destroyed so I cut the harness right at the n.s.s. pulled it up into the engine bay and twisted the b and c wire together. The new n.s.s. comes with the wires and plug.

tommyis3

Ok, I must be dumb, jumpin the two black wires, B+C still does not work for me.

Heres is what I have done:
Traced the wires from the switch on the transmission upto the engine bay, the wires go to a black connector at the side of the oil dipstick, the black connector has a clip on the side that allows the connector to be split open, I have opened the connector and I have jumped the B+C (two black wires) that is connected to the transmission end of the wire harness, is this not the right place to jump the wires?

I really dont understand tj40 post, sorry but I must be really dumb!!

What does work is having a pushbutton momentum switch from the small post on the solenoid and the + side of the battery, this works every time, but, what I dont like about this is the button can be pressed and it will turn the engine over without the key in, what I was thinking about doing is finding a live terminal in the fusebox, that is only live in the key start position, or should I be using a relay in the wiring somewhere.

Sorry to go on about this guys, but I really want to know how to do the NSS switch bypass.

Thanks for your patience with a dumbass!!

tj40

maybe your ignition switch has went bad? Ya, its hard for me to describe the n.s.s. thing. My friend Rob was doing the same thing while on vacation in TX. I was telling him to jump the n.s.s. harness he was jumping the wrong end the whole time, the end that connects to the transmission. I couldn't get him to understand that he needed to make the jump at the end that feed the under hood harness. It may be the ignition switch its just that 90% of the time its the n.s.s. I would try to hold the shifter forward while trying the key or try starting in neutral. I had to jam it in park to get it to start before I bypassed it.

tommyis3

Well tried the NSS bypass again and still no joy, so I`m thinking its the ignition switch, anyone know how to change the switch.

ET JEEP

Before changing out your ignition switch do a little more electrical testing. Your starter and solenoid work since you can start it with your jury rigged start switch.

You need to test your engine starter motor relay. There are 4 connections to this relay. The relay may be a 5 pin relay with one pin not used. The pins for this system are 30 power, 87 feed to starter solenoid, 86 power from the ignition switch, and 85 ground going thru the NSS.

When you turn the ignition switch to start, power goes to pin 86 thru to pin 85 thru the NSS to ground. This activates the relay. With the relay activated power goes from pin 30 to pin 87 to the starter solenoid/starter and the engine turns over.

If the NSS does not provide a path to ground in park or neutral, the relay will not activate and you get nothing when you try to start.

Pull your engine starter motor relay. Find pin 86 and 85. You should have continuity between the pins and a low ohm reading like 100 or so. Find pin 30 and 87. You should not have continuity between the pins.

Now attach some test leads to pins 86 and 85. Attach the lead for pin 86 to battery positive and lead for pin 85 to battery negative. The relay should activate and now you should have continuity between pins 30 and 87. BTW pin 87a is not used. If all this checks out the relay is good.


Testing for power at the relay socket. The socket for pin 30 should have battery voltage contantly. The socket for pin 87 should have a path to ground thru the starter solenoid. Do a voltage test at socket 30 for battery voltage. Do a continuity test at socket 87 to a good engine ground. You should have continuity.

Now when you turn the key to start, you should have power at the socket for pin 86. Test for battery voltage at socket 86 when someone turns the key to start. If you DO NOT have battery voltage then your ignition switch may be an issue.

The socket for pin 85 should have a path to ground thru the NSS. Do a continuity test at socket 85 to a good engine ground. If the transmission is in park or neutral and the NSS is good, you should have continuity.


Note that pins 86 and 85 can be wired in reverse. Normally 86 is ignition switch power and 85 is ground thru the NSS.

Hope this helps.

tommyis3

Thanks for the ET-JEEP.

I will check this out this weekend.

rustycar4wd

i have a 1992 Jeep Cherokee 4x4 that has just deleveloped a starting problem.
When he goes to start it, all accessories lights, gauges, fuel pump, etc come on, but when i turn the switch to start, nothing at all happens.
There is a click that comes from the engine compartment when I turn it to crank but nothing else. its just dead..... really dont know what to do.... im gonna fill the tank with gas and see if fuel pump is pumping fuel but it wouldnt be just dead it should at least try to turn over but not even......

Tests done so far:

i have changed fthe battery terminals...

Mason Slaughter

did you ever figure out the problem

BruceB

10 year old thread...probably will not get a reply