1JeepJeep

Hello. My first post here although I have been a huge fan of this site for many years as it has helped me through many a fix for my beloved jeep. Kudos for all the great advice I have gotten through others issues that matched my own.

So here is my new issue. I'll start with my basics. I have a 1998 Jeep Grand Cherokee Laredo 5.2 liter V-8. I have had many of the electrical issues discussed here throughout the years and have fixed most of them through all the helpful advice. Now I have some new issues that I am hoping I can get some help to diagnose so i don't have to throw money at changing parts until I know it is faulty...if possible.

So here is what happened. My wife drove our daughter to the hospital. After the doctor visit she came out and turned the key and nothing. I towed it to firestone to get a scan and they called back and said they needed to do their 109 dollar scan and that the 29 dollar scan was no help. So I reluctantly agreed. After that they called and said they couldn't fix anything, had no idea, and wouldn't do anything to it. The good news was they forgave ALL the charges. So at least they are honesty, albeit pathetic at car repairs.

So i paid the 85 dollar tow charge to tow it back home. I first tried the ole tried and true smack starter with hammer and see it it would start method.
That didn't work. So I got a cheap scan tool and put it on the Jepp and it came back with Err. It couldn't read anything. So I was on my own to figure it out.
I starter with the starter. I tried to jump start manually with a screwdriver on the 2 solenoid posts. I got spark...but no cranking at all. I removed the starter and bench tested it......incorrectly. I guess I didn't read how to do that correctly as I had attached the positive to the top post instead of the bottom post. But when the starter did nothing, I felt confident the starter was bad. After all I bench tested it...so I thought at the time.
So I go down, buy a starter/solenoid and bench tested it. This was when I figured out that I didn't bench test the old one correctly. I figured out my mistake and bench tested the new one correctly and everything seemed fine and dandy.
I installed the new starter/solenoid and was hoping it fixed the issue even though my expectations were tempered knowing that I hadn't bench tested the old one correctly.
After install I got in, turned the key, and .....nothing. Same as before. However, now I WAS able to manually start the vehicle using the ole screwdriver method to the solenoid posts. So even if my bench test was faulty, there was obviously improvement made by installing the new starter/solenoid.

So this is where I am at. I have checked the starter relay in the under the hood fuse box. I also checked the 40 amp fuse that is related in there. I have checked ALL the fuses actually and all are fine. I checked the 10 amp fuse in the passenger side fuse box for the starter and it was fine. I actually checked ALL the fuses there too. All were good.

My battery is no more than 1 month old and reads 12.4 volts. Good there. Connections are solid and tight and ground to side is solid and tight.

After reading several of your other threads I am leaning towards the ignition switch being bad. But I would like to know if there is a way to test this before I throw more money at it. I do not want to put a remote start switch in it unless I have too. I also do not really want to put in a ignition tumbler unless it is bad because of the new key issues it might bring.

But can you guys and girls help me diagnose my ignition to starter electrical problem here? I have digital volt meter and pen light and lots of determination to get this Jeep back on the road. This is my wifes car and she is scared to drive my truck. Plus this Jeep is family now. We got it after hurricane Ike destroyed our house and our 3 vehicles that used to work.
It has been a great Jeep through all the time since the hurricane and has been a life saver for us. Please help me get this Jeep back on the road. I will be coming back and will never abandon this thread like so many others seem to do. What good is it if you don't come back and say what fixed the issue?
I've seen that a lot and it is frustrating to read through a thread and the thread starter never comes back and says what happened.

Okay..let me know if you need any other details. If we get it running again, I'll start in on my other issues, like the horn, the radio, the windows, lol typical Jeep electrical issues. I am a carpenter so diagnosing electrical issues is not my forte. I have the wiring diagrams in the Haynes manual but I'm not sure what readings I am supposed to be getting and so I am having a hard time figuring out how to diagnose the issue of the key not starting the Jeep.

Thanks again.

Turbo X_J

Probably a wiring or connection issue.
Go over the entire engine compartment wiring harness and pay particular attention where it crosses over the engine behind the valve cover. Look for any chafing and/or broken wires. As well clean up all the under hood grounds.

ETA:
Sorry, I didn't mean every single wire, but the "main" harness that enters on the drivers side of the engine compartment and crosses over to the passenger side.

1JeepJeep

Every wire in the engine compartment? I'd like to focus on the ignition to the starter problem. Can you tell me what color these wires are? Is there a way I can test to see where the voltage is losing it's path?

I'd specifically like to know a way to test the ignition switch, which is what I am leaning towards being the problem.

My second possibility from what I have read, is the Position Crank Sensor. I have watched a video on how to remove and replace and so, I'd rather not deal with that until I get the ignition switch validated as good, and the ignition tumbler validated as good.

I'd be willing to follow the wire that could be my problem, but inspecting every wire in the harness all over the Jeep seems like a wild goose chase, no offense. I know these Jeeps used poor quality wiring plus put wires in exposed areas where they shouldn't be.

But since I am waiting on responses, I will go out and see what I can see about your suggestion. Thanks for the response. I'll report back any findings.

1JeepJeep

I took a look around. Everything is wrapped up in the plastic tubing and then factory wrapped in that black tape. I looked at the ends and connectors and don't see anything that stands out. Like I said, electrical stuff is not my forte.

I'd rather not open all these factory wrapped bundles to inspect unless it is verified we are losing the connection somewhere in between. Is there a way to verify my relay in the under the hood fuse box is getting the proper electrical response? If we can verify something is good, we can cut down where we need to look.

I have the testers, just don't understand wiring diagrams to know if I am supposed to get voltage, and how much, and under what conditions I am not to be getting voltage.

Here are a couple of findings that I can start with to begin eliminating ...

1.)The first with the key turned to crank, do we have 12 volts at the solenoid wire. Small wire to solenoid

2.)At the same time, do we have 12 volts present on the battery wire at the starter.

3.)Make sure the body of the starter does not register any voltage at all, at this time as well. It should register 0.0v-0.02. No more than that.



I think I can do these tests and see if I am getting proper current to the starter, (which obviously we are not somewhere or it would crank) But maybe these tests can help further my cause. If anyone thinks this test info is bad, let me know. I'll go and get the wife to help me volt test and report what I am getting there.

1JeepJeep

Findings:

Wires are still connected to starter.

Small wire/post -

Key off - .01
Key on - .06
Key crank - .03 - FAIL EDIT: I think at crank you should have no voltage here from what i read.

==============
Large wire /post
Key off - .4 - .6
Key on - 2.5 - 3 (fluctuated up as high as 6-8 momentarily but not consistently)
Key crank - 6 - 8 fluctuating - Below 12 volts FAIL

====================

Body of starter
Key off - .01
Key on - .01
Key crank - .00


=====================

Well obviously I am not getting 12 volts to the small wire and significantly less at the big post.

Should I be testing these wires with them disconnected from the starter?

Turbo X_J

Automatic transmission?
Have you tried moving the gear shifter or while in "N" with the key turned to "start"?

Jeep Driver

Yep, my first thought too.


NSS

1JeepJeep

Yes. It will not crank in neutral. I have read all about that Neutral Safety Switch on here though. That's how I knew to check that. I tried shifting it all around and it does nothing in park and neutral and wiggling around.

Remember though that it will crank up and start in Park by arcing the solenoid. So to me, that rules out NSS.

Tomorrow after work I'll take a knife to that bundled up wire package and inspect thoroughly although I do not want to. lol


Yes an automatic transmission.

Turbo X_J

It's not necessary to open it up, just check for any places that may have been chafed or damaged/burned. That fact you could not jump at the starter solenoid previously and now can sure points more towards a wiring/ground issue than the ignition switch itself.
You can download your own copy of the FSM with wiring diagrams from this site:
http://www.pacificcoastmanuals.com/j...e_manuals.html

1JeepJeep

Well remember that I installed a new starter solenoid between the time when it wouldn't arc and it would arc to start. So I was thinking that had something to do with it. But for it to be multiple things going wrong at one time does seem odd. Maybe the wiring is the issue. I'll look more closely at the bundle tomorrow in the sunlight. I didn't really see any damage other than 18 years of normal wear and tear.

My wife babies this Jeep. I don't think she has ever been over 45 mph in it in the last 9 years. haha That's how she drives. The Jeep seems to love it too.

I'll report back when I have finished a thorough wire bundle inspection.

Thanks for that link. I'll be checking that out too. I have a Haynes manual but the wiring diagrams say that they are a bit generic and may not be specific to my vehicle and it is hard to read the tiny print. I also am lost as to how to read a wiring diagram. It's a lot different than a blueprint to build a house.

CCKen

98 starter circuit:





PDC fuses:





98 JB fuses:

1JeepJeep

I can't see any wiring damage. There is a lot I can not get to to see though.

The wiring diagrams do not look like my jeep. Clutch switch looks like a standard transmission and my under the hood box has 5 point relays, not those large ones.

Is there a way to test signals at my relay switch?

Also that diagram looks like I should have 12 volts at the large solenoid bolt.

All the time. If this is true then I need to figure out why I have such a large voltage drop there. The most i read there was 8. Am i reading that correct? It looks like the battery+ is hooked up directly to the starter motor and should have 12 V. Does that sound right?

Jeep Driver

You've ruled out the NSS when you should not have.

A dirty switch will not make contact no matter where you place the shifter or how much you wiggle it.


Simple first, then complex.

Take it apart and clean it.

1JeepJeep

Okay. Thanks. That helps. This is why I am having trouble diagnosing. I do not understand enough to know when something is good and when it isn't.

Okay, i guess I am off to rewatch the NSS removal and cleaning video I watched last week. It's supposed to rain tomorrow so maybe I'll be able to get on it if it is a rain day. Thanks. I don't suppose there is a way to test the NSS before I remove and clean it up is there?

Turbo X_J

https://www.cherokeeforum.com/f2/wir...98/#post372618