Electrical problem, not sure where to start
 

Hi all, new here and to Jeeps, got my xj about a year ago. It's a 99 with the 4.0 and an auto trans.

I am having a problem that is happening more and more frequently, where I turn the key to the "on" position, but the gauges don't turn on, no warning lights or anything, fuel pump doesn't prime, but the radio and lights work. If I try to start, it just cranks but never gets any fuel.

I believe there is some loose wiring or something because if I smack the small dash piece to the right of the glovebox, or if I open the passenger door and slam it shut really hard, suddenly the gauges wake up and it starts just fine.

Around the same time this started happening, my keyless locks stopped working. I'm not sure if it is an oem keyless system or not, I have been using a oem jeep remote, but I looked up behind the dome light and there is no circuit board there. Not sure if this is related to the jeep not starting, seems like an interesting coincidence.

Sorry for the super long post, just not sure where to start with this, any help is greatly appreciated! :boxing:

I've got a 98 so your electrical should be identical to mine. On the passenger side under the dash closest to the door you'll find a fuse panel. I'd check for loose fuses. Thats what it sounds like to me. If all those are ok, there is another fuse panel under the hood on the passenger side, check those arent loose, although I dont think any of those have anything to do with the interior electrical but wouldnt hurt to check anyway.

OEM remote = OEM RKE. When you said "behind" the dome light what exactly do you mean? The RKE module is IN the dome light, unless someone moved it...

The RKE module is part of the CCD bus which the PCM uses to communicate with the gauge cluster and other fun stuff. If the CCD bus is corrupted it's very possible it will refuse to work.

Thanks, next time it happens I'll play with some fuses.

How would I check to see if the CCD bus is corrupted?

I'm sure there's some fancy dealer method using a proprietary tool but what I'm getting at is "find the RKE module, unplug it, and see if it starts" lol

Everyone on the Forum hates me so I won't show you how to fix it. So I'll wait and see if you can fix it. And if you can't fix it, you can come crawling to me and I'll show you how.

Har Har

Nonsense, who told you that? You're the only guy that knows '97+ fuse panel lol

My wife (the Beast) told me that. :-)

Merry Christmas Dudes and Dudettes.

:cheers: Ken!

I don't hate you :help:

LOL

Did you unplug the Remote Keyless Entry Module in the mini dome light (or overhead console) like Salad said?

Edit: Pic of RKE Module in mini dome light>

Attachment 318102

I did unplug the RKE, unfortunately still no start. On the plus side, I did find the RKE, so maybe I can replace that and get my keyless working again.

You may have a loose/bad connection to the instrument cluster causing the proble. By smacking the dash it brings things back to life would lead to thinking this.

You can check the CCD Bus to find out.

Review the CCD Bus schematic below. It shows the Data Link Connector and the various modules connected to the bus.

Do this test:

Remove the negative (-) battery post connector.

Using a digital Ohmmeter, set to 200 Ohms, read between DLC pin cavities 3 and 11. You should see 60 Ohms. If you see 120 Ohms, smack the dash and see if it goes to 60 Ohms. If you see 60 Ohms smack it again to see if it changes. If you see the resistance change by smacking the dash it is probably the instrument cluster connector C2, CCD Bus connectors (+) and/or (-).

Attachment 318051

If this test is inconclusive, reconnect the battery and check the voltages at the DLC.

Turn the ignition switch to ON, without starting the engine.

Using a digital Voltmeter set to 20 VDC, probe DLC pin cavity 3 (+) probe and pin cavity 4 and/or 5 with (-) probe. The voltage should be around 2.49 Volts. Repeat the test using pin cavity 11. THe voltage should be a bit higher.

Note the volltage tolerances on the schematic. If the voltages are out of range, smack the dash.

If the voltages stay out of range there could be a bad module on the CCD Bus.

The fix for the instrument cluster is to remove it and check the pin cavities in the connector to your right. That's connector C2. Try cleaning the pin cavities and reinstalling the instrument cluster and trying it again. If it still fails, Chrysler has a TSB kit that replaces that connector.

Also, consider what Rcrivolio said. Fuse #9 in the Junction Block powers the instrument cluster.

Revised previous post to show that the ignition switch must be ON (without starting the engine) inorder to take voltage readings at the DLC.

Thanks for the help everyone. Just to provide some closure to this thread, it turns out the problem was a loose connector behind the panel under the steering wheel. Wiggling it would turn the gauges on and off. It has been secured and all is well so far. Now to find a working RKE..