PDC

[JAG1]

Daleb, 

 

         Another item keeps ringing my thoughts.... you said the wipers came on by themselves even though the switch was off. Something is crossed there in that circuit causing it to get power when it shouldn't be powered up. My experience has been that when a switch gets old and worn it almost always fails to go on into the on position. so somewhere it may be getting power from another source after the switch.

 

Have you looked into the wires running down the steering column?

 

I don't like the added P/O fuse panel you talked about with the old circuit that it should have eliminated, but is still active because you found the old circuit fuse still there. Something isn't right .... try to find the reason that's been added and is still there. 

 

What's hard for me to understand is how failing burned contacts in a grid heater relay can burn my fuseable links to the starting ignition circuit(s) that are wired a few feet away. Just now learning that excess heat will do it's damage and show up at the weakest point in the circuit. I wonder if the P/O had this same problem from burned poorly connecting grid relay contacts and tried bypassing something he did not fully understand.

 

Edited April 7, 2019 by JAG1

[Daleb]

I thought the extra stuff under the dash was for the starter but its not because the starter works without it being hooked up. the light blue wire on the steering column is what its hooked to. Im going to have to trace the wires and see where they go. Cummins mechanic told me what to test on ecm to see if its getting power I will do that tomorrow.As for the wipers A bad ground can cause that sort of problem they seem to work fine now. This truck is quickly working its way to a ppump.

[Daleb]

Well there is a 98 24v in my area that just had his joint connection 2 burn up. That makes 2 total failures in the last few months also I have one here off a parts truck that got hot enough to blacken the plastic and have looked at a few others when I was shopping for my new harness that were the same. Im starting to see a pattern here that I'm not liking. Wonder If the early 24v are going to start having issues you all might want to pull the pdc off at the bottom and inspect joint connection 2 for signs of melting plastic.

[Tractorman]

Sounds like there might be a trend here - thanks for the heads up...

 

- John

[JAG1]

X 2

[Daleb]

I was just thinking if JC2 goes bad should we not be able to bypass it and run the wires to a new fuse block and join them there. Or does JC2 serve another purpose that could not be served by fuses?

[Tractorman]

57 minutes ago, Daleb said:

I was just thinking if JC2 goes bad should we not be able to bypass it and run the wires to a new fuse block and join them there. Or does JC2 serve another purpose that could not be served by fuses?

 

If I understand correctly, that junction connecter supports a few fused circuits and some other circuits.  I don't see anything stopping one from bypassing just one damaged circuit and leaving the rest intact, just as long as the new circuit has the proper size fuse and wire gauge.

 

- John

[Daleb]

Good news I got the truck running was a loose plug in the engine line out harness. Bad news is the head lights stay on and if I turn the head light switch on the truck quits. Also getting code p1689. I cleaned all the grounds as I installed the new harness. The head lights are on as soon as the key is on and the high beams don't work anyone know what other grounds could be the problem or might this be another problem?

Dale

[Tractorman]

46 minutes ago, Daleb said:

The head lights are on as soon as the key is on and the high beams don't work anyone know what other grounds could be the problem or might this be another problem?

 

If the headlight wiring is OEM with a factory one bulb per side system, then all of the headlight controls (headlight switch and dimmer switch) use the ground wiring side of the bulbs to switch the headlights on and off.  The headlights are fed by a hot lead.

 

Does your truck have fog lights? 

 

I am assuming your headlights were working normally before your problems with Joint Connector #2.  Try the following:

 

  *  Leave the key switch off and operate the headlight switch.  The low beams and high beams should operate normally.  If they don't, operate normally, then I would start my troubleshooting here. 

 

  *  If the headlights do operate normally with key switch off, then I would be looking for something powered by the ignition switch circuit that is switching the ground side wiring for the headlights to ground.

 

Sometimes when I am troubleshooting electrical problems I like to prove what is working correctly rather than trying to come to a conclusion that I can't prove.  For me, it is a process of elimination.

 

- John

[Daleb]

thanks I will try to see if lights work normally with key off.No the truck does not have fog lights.

Dale

 

[Mopar1973Man]

Since I made it home... 

 

Here is the joint connector 2 pin out...

 

Looking at the joint connector I'm going to bet money either the wrong fuse is being used or excessive electrical load is placed on the joint connector. Being a majority of it is +12V power supply and only 3 pins are grounds. Then being trailer power is from here then it could be a trailer electrical issue and/or wrong fuse size used. Yes, I've seen dealers increase the fuse size and cross out the old fuse size. 

Edited April 14, 2019 by Mopar1973Man

[Daleb]

The worst wires in the damaged pdc I have are melted at the wire thats goes to the fuel pump relay. I wonder If the damage was down when one of the original engine mounted ecm powered fuel pump failed and heated JC2. Maybe it was slowly deteriorating over the years until it failed. Might explain why there seam to be a bunch with the same damage. All my fuses in the pdc where the proper size but who's to say what was in there over the years.

Dale

[dripley]

The lift pump is fed directly by the ECM and does not go thru the PDC. In a stock configuration. The fuel pump relay in the PDC is for the VP.

Edited April 17, 2019 by dripley

[Tractorman]

20 minutes ago, dripley said:

The lift pump is fed directly by the ECM and does not go thru the PDC. In a stock configuration. The fuel pump relay in the PDC is for the VP.

 

@dripley, when my first VP44 failed 64,000 miles and was replaced at 87,000 miles, it was replaced under warranty along with the lift pump and the associated wiring.  At that time the factory fix was to install an in-tank lift pump and to relay that lift pump.  The coil portion of the new relay was triggered by the ECM, but I don't know where the power source comes from for the relay portion that actually operates the lift pump.  I was wondering if you might know.

 

I think I might have to do some investigating

 

- John

[dripley]

1 minute ago, Tractorman said:

 

@dripley, when my first VP44 failed 64,000 miles and was replaced at 87,000 miles, it was replaced under warranty along with the lift pump and the associated wiring.  At that time the factory fix was to install an in-tank lift pump and to relay that lift pump.  The coil portion of the new relay was triggered by the ECM, but I don't know where the power source comes from for the relay portion that actually operates the lift pump.  I was wondering if you might know.

 

I think I might have to do some investigating

 

- John

I still have the relay harness I got with mine at the house. It did have a seperate power source but I cant remeber where other than maybe battery connection to the PDC. Its been a long since I took that off.

 

The funny thing with my VP failure at 75k is they only replaced the VP and not the lift pump. It took another 75k for it to fail. Then I got the intank pump on my dime. But the VP on the truck lasted another 70k before I replaced it. It sid not fail but I had had some issues with it due to low fuel pressure and just swapped because I had the money then. 245k miles later it is stil going strong.

 

[Mopar1973Man]

On 4/7/2019 at 11:13 AM, Daleb said:

This truck is quickly working its way to a ppump.

 

I don't suggest this... Most end up losing MPG doing that mod. Then end up losing other things like cruise control. P-pump is great for racing but not for a daily driver. 

[Tractorman]

3 hours ago, dripley said:

I still have the relay harness I got with mine at the house. It did have a seperate power source but I cant remeber where other than maybe battery connection to the PDC.

 

@dripley, I checked where the power for the lift pump relay contacts come from on my truck.  As you suggested, it comes from the battery connection at the PDC.  A short distance away is a 15 amp in-line fuse.

 

@Daleb, I can't remember if you mentioned where your lift pump gets its power, so if you haven't checked, it would be a good thing to verify.  If the power for the lift pump is tapped into an existing circuit, the additional lift pump current could easily overload that circuit.  Ideally, the lift pump should be fused and relayed from the PDC and the coil portion of the relay triggered by the ECM. 

 

- John

 

[Daleb]

When I got the truck the fuel pump was in the fuel tank and was powered by the battery and the relay was triggered by the original connection of the ecm. When I put a fuel gauge in the truck I only had 6psi fuel pressure from idle to wot it never change so I bought a fass titanium and 1/2 inch fuel line. The pump is ran off the battery and the ecm triggers a relay and I run about 18psi. Now as for the head light problem they come on with the key on. With the key off they come on when I put the parking lights on. If I pull the head light fuse they stay on really dim. If I disconnect the day time running light module the lights go out but if I turn the head light switch on it still kills the motor if running. If I take the #1 50amp battery fuse out I can turn the light switch on with out killing the motor but the head lights are still on.Also I have no blower motor or speedo but all other gauges work and I'm not sure if the problems are all related.I am in the process of finding a good 2nd get mechanic because I think this electrical stuff is beyond me.

[Axel]

Does the PDC(fusebox/TIPM) in a 2001 Ram 3500 need to be reset by a dealer or can I just do a hard reset(unplug terminals, connect them, and turn on key for 10min to drain capacitors) myself?

 

Reason for question:

I'm planning on replacing mine with one pulled off a wrecked truck.

Mine appears to be malfunctioning.

Thanks