99 WJ electric system going crazy
 

Hello,

Just when I thought I was done with fixing things (https://www.cherokeeforum.com/f5/98-...cident-248579/), my little jeep (99 WJ, 4.7L, V8) started acting weird on me.
Here is a sequence of what happened:
1. the check gauges warning light lights up while driving, no problems for about 10 minutes
2. the abs light goes on, still driving no problem
3. airbag light on
4. (probably unrelated, but just in case), some brief transmission noise (like when it has trouble getting into gear), no problems of this nature afterwards
5. Radio went off
6. dashboard main lights (not the warning ones) off, as well as the console
7. Speedometer as well as other meters (electric, oil, temperature) go to zero and cabin lights turn on by themselves, not as bright as they usually are
8. red car warning light on as well as seat-belt light
9. driver side blinker sound on, although not as strong as when I turn
10. Front lights go off (it was the worst part since it was night)

All this happened in about 25 minutes and luckily I was able to get off the highway and reach a friend's house.

11. After I get there, I turn off the car and then try to restart it, but it feels as if there isn't enough juice (but lights and controls are back to normal).
12. wait about an hour and try starting again: it starts!
13. I let it idle for 5 minutes and steps 1-10 happen again, in a much shorter time, engine still running.
14. Turn it off again, since I did not want to try driving in the night without lights and risking to end up stranded
15. Tried turning the car on again, and again, no juice feeling (the starter makes it usual clicks, but the engine does not start)

Took a uber home.

It seems that similar electrical problems are relatively common on WJs with tons of different approaches (cleaning connectors, checking for broken wires or solder, replace fuses, change alternator, replace PCB etc) and I am wondering, strategically, what's the best approach to take.

Any advice on the steps I should take, in order to properly diagnose the problem and solve the issue with the least amount of work and money is appreciated.
Things such as what to check first, and how, what to change, possibly links to solutions/write ups, even just parts of the process. All is welcome.

I'm a newbie to the Jeep world.

Thank you

I had very similar instances on my WJ, but it always ended up with the car just cranking and not starting, allot of funny business while driving around, random stuff not working...

It was all related to the vehicle security system (SKIM) reader. It can malfunction & stop reading the security key correctly & basically screw you in so many ways. In fact I had so many problems with it that I ended up having the mechanic make a new key that we duct taped to the skim module itself because of how finiky it became... Not saying this is your issue but it could be.... Do some searches on the SKIM & WJ security key etc.

Thank you for the advice.
This weekend I'll try with the other key and see what happens!

Another choice is to junk the vehicle.

A week ago, I had similar problems. Airbag light, rear defrost indicator, and park lights wont shut off. Seeing you are in MI, I would speculate you may have a similar situation. We have had a couple decent snows here and I drive the highways a lot. So a lot of slush. Then I went to the car wash and did the wheels and wells. My fuse block in the passenger side footwell had taken on water from the wheel well where it is welded together had come apart slightly and was letting it in. Long story short, I removed the entire fuse block, and found it is pressed together with layers of steel circuitry in between. Well, those sandwiched layers were bulging and oozing with bright green funk. The whole thing was toast. $400 at the dealer, but they didn't have any, out of production. So off the the junkyard, and the first zj I walk up on, there is one already pulled on the passenger seat, and it is as pristine as the day it was made. 13 plug on connectors, something like 5 relays, and the flashers..Oh and I also needed a couple of the connectors as when I pulled them the pins were corroded right off. Ha, I say to myself this may explain a lot of flukey stuff going on for years. Got it home and in, and everything is perfect as the day it was made. Blinkers go klunk! klunk! and everything is bright and nice.
Just sayin. Oh the cost...$21 with tax.

Good news :)
I checked the battery, and it wasn't working as expected. Luckily I had another one, but after replacing it, somehow it wasn't charging consistently.
Checking the alternator, I found out it was not functioning so I replaced ($150) it and now all is fine again!

On a side, I also found that the wires of the electric fan had been cut open by the clutch fan when I used the jeep for a short trip before replacing the fan shroud. Fixed those as well.
Perhaps they are the cause of the failing alternator that then ruined the battery.

Thank you all for the help.