Paul Distefano

Does anyone have any idea where I may be able to find an engine wiring harness for my 1999 Cherokee Sport? I recently needed to replace the PCM because I was getting the "no bus" error on my odometer. My problem is that I cannot get this thing to pass inspection because there appears to be a break in the circuit between my fuel pump relay and the PCM. I have had four OBDII codes which keep coming up in the "not ready" state as soon as I shut down the engine. Apparently, I can drive the car and get at least some of these monitors to read "OK", but this break in the A61 circuit is preventing the PCM from retaining this in memory. Dealership says that the harness is no longer available and they are hesitant to try to get into the harness to try to splice in a new wire because they feel that due to the age of the Jeep, it is too fragile and likely to cause additional problems. I am hoping that someone here has a suggestion....... my Cherokee is coming up on 400,000 miles and still runs like a champ, but my inspection sticker is almost two years old! I got NJ DMV to give me a letter to keep in the car with a two year inspection (after attempting to go through inspection several times) because they could not get a good reading. Shockingly, I have only been pulled over once, but every time I drive her, I get paranoid! If anyone has advice on where I may be able to locate one, it will be greatly appreciated. I cannot seem to find anything online. Thanks, and Happy Holidays to all.

PD

Ralph77

I think, operative word being think, this might be the one you want. Best I can tell this would be for a '99 with a 4.0 automatic that does not have ABS, Daytime Running Lights, or Fog Lights. Now what shape is this in? Will it solve your problem? Who knows.

https://www.ebay.com/itm/1999-Jeep-C...temCondition=4

Scroll down to the same part number to read the parameters.

https://www.factorychryslerparts.com...duct=4570479#1

Paul Distefano

Thanks Ralph. I am going to contact them. No fog lights or DRL, but do have ABS.

Ralph77

If that is the case I don't think that is the one for you. Trying to decipher what one it might be a that second link can give you a headache. Good luck.

jordan96xj

Something seems off there. If the PCM could not provide its ground to the switch side of the fuel pump relay, then the fuel pump would lose power and leave you walking. But that does not match up with the rest of your post, where it would seem the vehicle is running fine. What lead you to suspecting that this particular circuit was damaged in the harness? was it something a mechanic or friend suggested?

Paul Distefano

You are correct........ and very observant! My apologies, but I had neglected to mention that before I brought my Cherokee to a dealer, and before the real cause of the problem was discovered, I had brought her in to my regular mechanic because I simply could not get it started. It would crank until my battery was dead, but would not start. He had identified that there was no ground to the fuel pump relay and this was why the Jeep wouldn't start. He had also thought there was a problem with the ground circuit for the auto shut down relay, but I had been experiencing issues with the PCM, including getting the "no bus" thing on my odometer readout and he thought my PCM was malfunctioning anyway, so he jury rigged a solution to get the thing started by running a wire from the power distribution center directly to the ground terminal of the battery to provide a ground for the fuel pump relay. Without that wire run, the Jeep will not start

I had pointed this out to the Jeep dealership service manager and technician when I brought it in. They performed voltage drop tests on the electrical wiring and determined that it was that particular circuit that was damaged in the harness. Because my Jeep is just shy of 20 years old and has 400K miles on it, they worried that if they tried to get into the harness to re wire that one circuit, they would probably create more problems. Unfortunately, they tell me the harness is no longer available and I have not been able to locate one myself. In the state of NJ, a vehicle of this type would be exempt from inspection if it were a 1995 or older. I am trying to get an OBD bypass exemption from the state now, but have been initially denied. In the appeal process now. If that is denied, I may need to take the chance at a repair if I want to keep her on the road....... but it would just be easier to replace the harness if I could find one!

jordan96xj

I see. Thanks for the clarification.

I don't believe any aftermarket recreations of this harness are being sold. If they are, I have not bumped into them. Many will suggest trying to get them from a junk yard. That option doesn't work as well these days as it used to, because there are pickers that clean these vehicles out at the junk yard to list the items on ebay. Most of the XJs at my local yards are completely stripped of every valuable electronic component. Only body, trim, and rusty suspension items remain (if that). So I just go straight to ebay these days, and skip the junk yard step (I think of it as paying a small premium for someone to go to the junk yard for me).

If it was my own harness, I would simply troubleshoot then add new circuits to the exterior of the existing harness as needed. Like what your mechanic did, but not a work around going directly from the battery.

If there was a ground from PCM problem on the ASD relay, ignition would be disabled (no spark). So I would be testing/diagnosing that and running that back to the PCM.

Just because adding a ground between the battery and fuel pump directly allowed it to operate, does not mean the PCM is bad. In order to blame the circuit you would have to confirm that the ground is being produced at the PCM connector, but that it never reaches the associated relay.

Fuel Pump relay ground, and ASD relay ground are grounds that the computer are going to disable when it is not happy with things (like a missing crankshaft position sensor signal, etc.). So I would have a hard time taking someone's word for it that the PCM is bad or that a circuit is bad. Did they confirm that the PCM was -actually- producing the ground, but that it wasn't reaching the relay?