No power to ECM

[Hollywood142]

I just replaced my chassis batteries on my 2001 Monaco Knight and now the wait to start light doesn’t come on and no fuel is getting sent to motor. Monaco hasn’t been much help so I had Cummins send a mobile tech out to look at it. $700 later he tells me that there is no power to ECM and that since he didn’t have a wiring diagram that it would be an additional $160 per hour to follow wires to finish job. Since all I did was switch batteries I dint think it was necessary to follow wires and that it had to be a fuse,relay or I didn’t hook up batteries properly. Does anyone have a picture of how this model should be hooked up or any ideas of things to check?

[FL420]

This is a real shot in the dark but is it possible that when you hooked up the battery cables on the new batteries you might have lost track of and failed to hook up a small gauge wire to the batteries?
The pic below shows two wire bundles connected to the negative terminal of one of my 12 volt chassis batteries on my '05 Monaco Knight.

[Hollywood142]

This is how I have it connected.

[FL420]

Originally Posted by Hollywood142

Attachment 283014

This is how I have it connected.

Did you clean and wire brush all the ring terminal connectors and battery posts when you installed the new(?) batteries?
I would clean all the posts and ring terminals and reassemble them tightly, especially the terminals attached to the 4 white wires and the wire(s) in the black wire loom directly under the white wire's ring terminal on the negative battery post.
That might do it but if not I would have a helper monitor the dash lights while I gave each small gauge wire a wiggle test along the length of each wire looking for an intermittent open in a wire.
If that doesn't work I'm all out of altitude, airspeed and ideas.

[RamiDav]

I'm pretty sure FL420 is on the right track .

Did you take a picture before ?

[153stars]

I have read many times that a wire that a wire disappeared by gravity or wire stress. I looks like many smaller wires have been combined into loops you may want to cut away the heat shrink to look for corrosion. Then get HD heat shrink in proper color to help in future.

[Ivylog]

Find the small red/positive wire you didn’t hook back up.

[Jeff753]

On mine the ecm is wired directly to the chassis battery along with things like smoke detectors etc. when I had master tech put batteries in they crushed and severed the ground wire (and blew up my odometer).
You are likely missing a small wire. Take them out and look again

[kidz_driver]

One other diagnostic check.

Does your transmission shifter pad light up?

There is an interlock between the TCU and the ECU and if there is no signal from the transmission the "wait to start" light and lift pump will not operate.

Power to the TCU is usually by a separate wire with a fuse which often is overlooked when re-installing the batteries.

if your shifter pad is not lit up, check for that wire and the fuse.


Dave

[ronster]

Most diesel computers are wired directly to the battery,about 10 gage wire with a fuse holder.Some Cummins have 2.Bet one got lost!

[Hollywood142]

Thanks FL420 I actually took a grinder to the wires to make sure I had a good connection and have looked many times for a missing wire. When the Tech hooked up to ECM his diagram said it showed 4 positive leads into ECM that weren't showing any power. Monaco has said that the ECM is powered directly to the battery as well but there is no bundle of 4 red wires anywhere to be found

Kids_Driver I do like where you are going with this but my coach has a shift lever not a pad and I don't think it typically lights up anyway. Something I didn't mention before is that I did find a blown 20amp CLTCH fuse in the Monaco #3 panel that I replaced. Not sure if this could be related. I do have the red wire hooked up with 60amp fuse in it and it does have power to fuse. There is also a small Orange wire with a 15amp fuse on the house side but I have deduced that this goes to the generator which does start and run fine.

Ronster and Jeff753 I have heard the same thing from Monaco but I have looked several times and had 2 diesel mechanics look at it as well and no extra red wire laying around.

Thanks for all the great ideas. This is much more assistance then I have gotten from Cummins and Monaco so far. I appreciate everyone taking the time to help out!

[FL420]

Originally Posted by RamiDav

Did you take a picture before ?

An excellent question and an important suggestion.
With a modern smartphone and a good camera it's very easy to take and save before and after photos of every system you need to work on. It aids in understanding, troubleshooting, repairing and returning your systems to operable conditions.
I have never taken a selfie but I do have a selfie stick which allows me to put my cellphone camera in places I could never reach or fit into otherwise. I have taken photos of just about every part of every system in, on and under the coach I can access. I concentrate especially on connections, Model Numbers, Part Numbers and Serial Numbers. I then organize the pics into system albums to find what I want easily.
It never fails to rain when I need a model or part number but I no longer have to get wet to find the info I need to find and order a replacement part online. It's on my phone.

[Jeff753]

Originally Posted by FL420

An excellent question and an important suggestion.
With a modern smartphone and a good camera it's very easy to take and save before and after photos of every system you need to work on. It aids in understanding, troubleshooting, repairing and returning your systems to operable conditions.
I have never taken a selfie but I do have a selfie stick which allows me to put my cellphone camera in places I could never reach or fit into otherwise. I have taken photos of just about every part of every system in, on and under the coach I can access. I concentrate especially on connections, Model Numbers, Part Numbers and Serial Numbers. I then organize the pics into system albums to find what I want easily.
It never fails to rain when I need a model or part number but I no longer have to get wet to find the info I need to find and order a replacement part online. It's on my phone.

Do you have small wires directly wired to the battery? How many positive? How many negative? Hopefully an equal number. My ecm issue was a crushed negative.

[FL420]

Originally Posted by Jeff753

Do you have small wires directly wired to the battery? How many positive? How many negative? Hopefully an equal number. My ecm issue was a crushed negative.

All the 5 white wires on one ring terminal and the 2 white wires on another ring terminal are connected to one negative terminal of one of the two chassis batteries. The only other small gauge wire attached to the other chassis battery is the ground wire from the TRIK-L-START to the negative terminal. There are no small gauge wires of any color attached to a chassis battery's positive terminal.
Hopefully I understood your question and answered it properly.