Noah911

I just figured it out that dashed line (the lighter colored one)!

I am going to post what it was that helped me. It means they are part of the same connector. Which now makes sense.. maybe?

Noah911

X1997J

That does make sense. Thank you.
Maybe I can unplug the o2 sensors and see if the fuse still blows?

Noah911

I never thought of that... it sounds like a good idea to me.

awg

You could try, but I dont think your vehicle will drive with front one disconnected, and as your problem seems to be intermittent ??, possibly not feasable

I would look very close at the coil, wires & connector, and also at the wires underneath the fuse as there can be corrosion from moisture

Noah911

I agree, as disconnecting it would not really be able to provide you with a definitive answer. You would still have to find where the problem is after doing that anyway...

BlueRidgeMark

No, disconnecting them will definitively tell you if the problem is there, or somewhere else. If the fuse does NOT blow, then you know it's in that circuit beyond the disconnect point. If the fuse blows anyway, then it's somewhere on the side of the disconnect point.


The engine should still run, but super rich. Not a problem for a few moments of diagnosis.

awg

In my opinion, you provide high quality diagnostic pointers for those who are having these sorts of issues

I am a qualified Electronics Technician, (a long time ago though), so probably had more practice than you at reading circuit diagrams

Nevertheless, I still have to look at the " legend" to work out what various dotted lines and arrows are supposed to represent, the whole diagram, its sub-sections etc

like anything relatively complex, it must be broken down into a logical step-by-step approach to understanding (of circuit diagrams)

You are miles ahead of the pack...I feel very sorry for people attempting to maintain an XJ with no electrical knowledge

X1997J

If I have time today hopefully I can get the jeep running again.

dave1123

Just to clarify, these wiring diagrams are misleading sometimes because a component with a dotted box around it doesn't show all the circuits in that component, but one with a solid line, does. The major problem I have with the FSM diagrams of fuse boxes only shows circuit numbers for each fuse, not it's function. You have to go to a circuit list to see all that is on that circuit. The FSM connector pinouts are a lifesaver though.

This however is the type of circuit diagram you can get by subscribing to an on-line service for technicians;

X1997J

So I unplugged and replugged every plug/wire harness including the o2 sensors and what do you know, it started right up and not blowing the fuse anymore. Kinda weird to me especially since I still don't know what the exact problem was.

I guess the new problem is the CEL is on and there are 5 codes that I picked up from my scanner;
P1694 manufacturer control
P0443 evaporative emission system purge control valve circuit
P0118 engine coolant temperature sensor 1 circuit high
P0700 transmission control system (Mil request)
P1492 manufacturer control

So ya, I'm not sure where to go from here.

BlueRidgeMark

In the act of unplugging and plugging in connectors, you moved wiring around. I"m betting you'll find a wire that has the insulation worn through somewhere. You moved it so it's no longer touching a ground, and so the fuse does not blow.

It will be back.

X1997J

I figure it'll blow again since the problem wasn't fixed but any guess on all those CEL codes? Thanks.

X1997J

I did pull the computer and on one of the bottom corners there was some corrosion but I cant tell if its just corroded on the outside of coming from the inside.

dave1123

Okay, now with it running move all those connectors you just unplugged one by one, flexing the wires as you do it. You'll know when you've found the right one.