fade94

A few months ago I stopped to help a guy that had the plug that plugs into the LP short out on his 99 CTD.
Well, it happened to me last night. No wires touching anything, factory harness. The plastic that surrounds the wires at the plug melted allowing them to touch. When they did, it blew the 40 amp relay/fuse in the distribution block.
So now I'm wondering just how many lift pumps aren't actually failing? Could it be the plug itself is what is failing and taking them out? I cut the plug out and bypassed it until I can order a different type of plug that this can not happen on.
Just wanted to pass the info on so that everyone can take a look at this plug on the harness side and make sure that it has not gotten hot and is about to fail.

JSPulliam21

This is one reason I think that a warning light, in addition to a gauge, is a good idea. It will immediately alert you to a problem when you may not have your eye on the gauge.

nickg

Maybe its the LP causing the electrical load which is taking out the plug

fade94

That could be also. I have had a FASS system on mine for several months now. Since my truck is 6 years old, it is very possible that when I lost my LP before, it took out the plug.

I looked at the plug closer tonight since it is no longer on the truck. The negative wire actually spins inside the plug. It won't pull completely out, but turns freely.

SCARY STUFF

Totallyrad

What gauge wire do they use on that plug?

fade94

Maybe 18 or 20. I'm thinking it's 20. Not very big at all for the load it is under. If I get ambitious, I'll track that sucker down and replace the entire power wire with some 14 or 16 gauge.
I swear some of the things I have seen that Dodge has done in building these trucks amaze me.

bnold

If you have a full FASS that plug should not be carrying much current at all... should only be tripping a relay correct?

Totallyrad

40 amp relay and 18 gauge wire seems a little mismatched IMHO.

fade94

It tripped the relay as well when the Dodge wire plug went nuts.

bent valves

I also had questions about the wiring to the lift pump and being curious, I did some digging. What I found out about the lift pump wiring and connectors follows:

Deutsch makes the lift pump connector. It is the DT series P012. It is designed to carry 13 amps continuously and is used with 18 AWG wire in our application. The maximum current that the lift pump can draw is dependant on the pressure it is making and is a maximum of 4.8 amps with the pump dead headed, or blocked off. The 18 AWG wire will allow 12 amps of current to flow without a problem. The connectors consists of a female end which connects to the ECM, part no. DT04-2S and a male end that is attached to the lift pump, part no. DT04-2P. These connectors withstand immersion in 3 feet of water without loss of electrical qualities or leakage. They show no evidence of corrosion after exposure to 48 hours of salt spray per MIL-STD 1344 method 1001.

I guess those having problems with the lift pump connections must have experienced 49 hours of salt spray.

fade94

That is all well and good. However, I pulled the plug apart tonight. The negative terminal has come loose INSIDE the plug itself and contacted the positive side. A closer look found that the tab that holds the male post in had failed letting it shift.
No saltwater involved.

nickg

It can be loose in the plug BUT once the plug is pushed onto the LP it should be tight, if it was making a poor contact then it would melt down, maybe with the failed tab, when the plug was pushed on the terminal it was not seated properly.
Are you running thru an extra relay and using the existing LP wire for the trigger wire for the extra relay? or have you plugged your existing LP wires to your new pump?

fade94

The way the FASS comes, you just uplug the LP and plug right into the FASS harness. The harness has a relay already.
I just put this post out there so that people could be aware of a problem I have seen on two occasions now.
I'm not trying to open a big debate on the affects of salt on the system or anything else. Just an FYI for guys to check as part of normal PM.