The advice about cleaning/checking your grounds is good counsel.

Here's some pics of the ground points in your engine bay. The pics are noted with the circuits the grounds serve.

After removing (and cleaning) the ring terminals, I recommend using a product called NOALOX, made by Ideal Industries, and available at Lowes and Home Depot, to coat the ring terminals before reassembly. NOALOX is an anti-oxident/conductor.

Grounds:









The strap at the firewall (pic) is supposed to be for radio frequency interference protection but I think you should address the connection at the fireall. I found mine to be corroded but it did not have any affect on my radio function, nor did it do anything after cleaning the connection. G100 is the main battery to chassis ground connection.

 

As I recall, there was another XJ owner that was experiencing problems like yours. His JB was [somewhat] clean but replaced it anyway. He found the C4 connector, and others, at the JB were badley corroded inside the connectors and had to replace most of the harnesses going to the JB.

 

Thanks Ken.

 

does anybody know where connector C201 is physically located?

 

Yes, I redid all the grounds in the above pictures, and took a jumper cable from the negative terminal on the battery and clamped it right onto the engine block, didnt make any changes.

ok.. here's what i found and what i did... I can remove the #6 underhood fuse, and the truck will still start and run (also, even with that fuse removed, the blower will still function normally from its switch, but doing so still causes the engine to stall). I cannot unplug the HVAC control head or the truck will stall and become a crank/no start condition until it is plugged back in. Verified G108 to be clean & tight.

heres where things get a little interesting... the a/c blower relay, behind the glovebox has 4 wires going into it, Green, Black, Blue w/white stripe, Red w/green stripe... If i unplug the blower relay the truck will stall and become a crank/no start, until it is plugged back in. however, if I apply battery voltage to the Green wire, the CEL will come back on and the truck will start and run, even with the relay unplugged, so long as I keep applying voltage to that wire. Do you think we're still looking for a ground issue, or some sort of power draw that the blower is causing on the PCM somehow??
I also tried leaving the blower relay plugged in, applying 12v to the green wire, and then turning the blower fan on by its switch but the truck will still shut off when i engage the blower.

It may also be worth mentioning the jeep has had all underhood A/C components (not recently) removed; compressor, receiver/dryer, condensor, refrigerant lines along with the pressure switch.

I've also noticed that with the key on and engine off, if i turn the blower on, and turn it off, the fuel pump will prime itself when the blower comes to a complete stop, as many times as I do it. The black wire at the blower relay only has ground if the blower is at a complete stop.

 

Read this NAXJA thread:

http://www.naxja.org/forum/showthread.php?t=1097000

 

I did, thank you. I'm going to try that on Monday when I can get to the junkyard.

Just to clarify, that was the section of harness that runs from connector C-201 (located on driver's side under dash) to the passenger compartment junction block, correct?

 

Not sure.

I think he referred to the connector C209 harness as having the problem.

You should check the connectors coming off the JB for corrosion before replacing harnesses.