Chrysler put the PCM behind the fender well on the front driver side below the window washer bottle. Unplug the battery, take the fender well out and check the wiring (pull plugs and check for corrosion in the pins) I had the same issues and I had to not only rewire all the plugs but I also put a new PCM in. There is also a collection of grounds on the inside rail of frame on the driver side (above tranny). I Found the electrical diagrams for the grounds and checked for back voltage and I was seeing like 0-5v on my grounds (which means it was shorting out). some of them there wasnt even continuity to the ground. I said screw it and followed the grounds I was having issues with and made my own grounds where they were attached to. I think I used 4 tubes of dielectric grease and a bunch of sandpaper to clean the terminals. After I was done wiring the PCM (had to make new brackets and everything for it to be mounted, good thing I have access to a laser and press break) I Fluid Film'd everything to help keep corrosion down to a minimum. Hope this helps.

 

I had flickering lights and strange behavior for a while. Was pretty sure it was a bad ground. Like Shep I also found ground connections on the inside rail of frame corroded. Cleaned them all and even added an extra cable from battery negative. Seemed better for a while, but not good. The washer pumps then stopped working. Traced the fault back to the same point again. Found several wires to be corroded off from the bunch of wires ending in same wire lug. They were held in Place by dirt and pressure from other cables and looked ok until i pulled them out. Replaced all the lugs and my problems disappeared. Later on I also had the classic problem With the Earth cable to the engine corroded off. Not impressed by the quality of the cables.

 

I'm having this issue as I speak, codes uo155-lost communication with instrument cluster (IPC), u110c-Lost fuel level (open in circuit between the PCM and BCM or faulty BCM, Po660-Intake manifold tuning valve control circuit open bank 1, problem while ignition on and car running ,will not shift, head and taillights not working, front wipers, power windows, radio, havac not working, speedometer and tachometer bounce, ABS , Brake, Traction Control Indicator, Airbag light and of course Malfunction Indicator Light all stay on, turn car off all lights work, can shift while running using pink by-pass, car idles and runs fine, fixes and testing ive completed: All fuses and relays are live and functioning properly, resetting codes thru terminal disconnection worked a couple times going to check ground under battery holder and remove ignition switch and test, any other suggestions or cures help would be appreciated

 

I too have the same problem. The clicking of the relay, I pulled it out but the right foglight is what is flashing. All fault lights on the dash are on, wipers don't work, radio doesn't work, HVAC doesn't work. I thought it may be a grounding problem but haven't gotten around to checking all yet. I starts fine, but you cannot get it out of park, I know someone wants to say the broken interlock but it is doing what it is suppose to do, it has to be electrical. I have extra TIPM's (fusebox) and BCM"s which I have switched out, but no difference. Well, back to work, if someone comes up with something, let me know. I'll keep looking.

 

found problem: for all having aforementioned electrical problem, if you remove your battery and tray, looking down on wheel well there are three ground posts, the one to the left (front of vehicle) and lowest is the faulty ground there are four(4) wires coming from harness on bottom these are clamped together with one post fitting, and there is a separate ground coming from harness at headlight, if they haven't broke off they will clean and replace post fittings, clean post itself, this should take care of problem. As a recommendation while your there clean and or replace other two(2) grounds and posts. Hope this helps it repaired my problems