Wiring Schematics for M1078 (1997 with new C7)?

[spoonbender]

Hi all,

I have a new-to-me truck - and it's time to get it running, as it's been sitting for over a yeary now...

After I took delivery with little info and dug in, I found out a few things:
- 1997 truck
- current wiring/boxes (dill boxes?) - no fuses (this was confusing until I got the cab raised and saw the next item...)
- C7 engine - appears to have never been run
- all kinds of extra parts in the cab - full extra dash, gauges, wiring harness - apparently they removed and left in the cab.

Appears in 2014 they did an overhaul, installed a new C7 - but never fully finished. Headlights, wipers, blinkers, etc all work - but no starting - just a relay click. Looking at the engine, appears they were either flashing the ECM/ECU and/or troubleshooting, as none of the gauges/wiring are connected - and a "diagnostic cable" is still connected coiled up.

I found a mechanic - current tech in the reserves, but he's having issues accessing the info he says he needs. I can post plenty of pictures if helpful, but my real question is - is there a current wiring schematic I could get him to assist? I found a schematic, but it references the older reset-able fuses/board. The wiring is similar, but ... different. I know I can trace each line, and eventually figure things out, just asking if there's a better way.


Thanks all in advance!

 

[coachgeo]

nope.... the schematics are inside software now... and software for that not released by govt.. Closet you will get is what his Guard mechanic can get for you thru their software or the older version for A1 (maybe better said A0.5) that can be found in TM section of S.Soliders. it is a separate post to the one in their about all the TM's for FMTV's.

You likely also should pick up schematics for any generic truck and/or tractor with C7 to help you make heads/tails of things. Oh.. and what is transmission model number in it? (aluminum tag, driver side? behind battery box on trans. impossible to see. (phone stuck in their take pic?) Also need to know what Keypad you have for transmission.... what does it look like? take picture ? Is a harness attached to the transmission yet... if so where does it go from trans back toward cab.... hooked up there anywhere yet?

 

[GeneralDisorder]

I find it unlikely that a qualified Reserve technician can't figure out the schematics for the various models in question. It's all readily available in EMS-NG on his MSD3 or MSD4. I find it more likely that he doesn't know what to do with this information in terms of how to adapt the C7 to the A0 chassis because this isn't covered in any of the military technical manuals since the military never did this or offered this as an upgrade. He's probably in way over his head trying to tie a WTEC-II to the C7 and install the A1R PDP into an A0 truck.

And the people that can figure this out - their time is exceptionally valuable. It will probably cost more to get this truck running and properly functioning than you think. In the end probably cheaper to just pickup an A1R and get the newer transmission along with the C7 and factory wiring.

 

[spoonbender]

Yeah, had a feeling this was perhaps a "whoops" - and dumped parts into the cab. (I realized quickly I was in over my head (!) ... sigh)

I'll get pictures of the transmission, and see what I have. Truck is about 45 min drive away, and that is one part I did not capture yet. Will report back here when I get time to go for the drive soon.

I did see 3 of these odd parts in the cab (very odd being 3 - one still in the paper wrapper), and when I researched, appeared to be controller/something to do with the transmission, so believe you are both onto something.

 

[GeneralDisorder]

The crank circuit will not operate till the transmission controller powers up and engage the neutral start circuit (confirming the transmission is in neutral and it is safe to start) that allows the PDP circuits to pass power to the starter solenoids. My guess is they couldn't figure out this system and/or the truck has a bad trans control module - not unheard of especially on the A0 trucks - or worse they have wired it in such a way that it damages transmission control modules. At this point it's going to take sitting down with several schematics and verifying the trans module has everything it needs to power up without damaging it - and the A0 trucks had a separate relay module used with the transmission controller that was later integrated into the newer style PDP so you will have a bunch of redundant and overlapping circuits. Honestly it's going to be kind of a mess I'm sure. Especially since you have no idea what they did or did not do and ultimately were unsuccessful at the attempt. Could be a lot done wrong in the attempt.

 

[spoonbender]

Got a little more info - pictures attached. Appears the transmission controller is from 2017, so not sure when the overhaul was attempted. Tried to get pics of the silver transmission tag, controller and dashboard transmission controller - as well as the lines from the cab down, and into the transmission unit itself. Appears all wires were intact, but I didn't trace them all through the runs.

Had to take these quick - a bit chilly outside today (high of 0) - let me know if any other pictures/info helps with a direction...

Is the transmission old or new? Is this as hard as first thought?


Thanks much!

 

[GeneralDisorder]

Well that appears to be the original 1997 MD3070 transmission - which was originally either a WTEC II or III. The transmission control module and the shift selector is for the WTEC-IV 3700SP transmission used in the A1R trucks starting with transmission serial 6510653277 and later.

The two transmissions have different wiring harness connections - the older one is a round connector on a short harness from the transmission body just forward and above the data plate. The newer 3700SP uses a rectangular bulkhead connector in a similar position.

I do not know if the 3700SP controller can work with the MD3070 internal components - it may work fine or be possible with the right combination of parts. But the wiring will have to be "customized" to connect it together if it hasn't already and since the truck doesn't run I've got to believe it potentially hasn't been done or hasn't been done correctly or mistakes were made elsewhere.

 

[spoonbender]

Thank you sir for sharing your knowledge. I'll start digging around for schematics/specs, and see what I can find. If I can find a solution, I'll share it here.

 

[coachgeo]

Got a little more info - pictures attached. Appears the transmission controller is from 2017, so not sure when the overhaul was attempted. Tried to get pics of the silver transmission tag, controller and dashboard transmission controller - as well as the lines from the cab down, and into the transmission unit itself. Appears all wires were intact, but I didn't trace them all through the runs.

Had to take these quick - a bit chilly outside today (high of 0) - let me know if any other pictures/info helps with a direction...

Is the transmission old or new? Is this as hard as first thought?


Thanks much!

ok.. so it is an MD3070. that is the original trans to the 3116... it mayyyy have got internal wire harness updated..... may not. See https://www.steelsoldiers.com/threads/md3070-vs-3700sp-allison-7speed-tranny-in-these-trucks.154061/

not real familiar with the M1078 A1R or A1Rp2 to know if that trans key pad came from one of them or not. It is NOT from an A0 or even an early A1 if I recall right. Never seen that one actually. Others will chime in soon.

PS- where are those pics hosted? IMHO move them to here since they are hosted elsewhere.. your thread can end up being very informative for someone in the future...... or complete JUNK since pics hosted elsewhere pretty much always go bye bye, rendering the info. in threads on a board like this mostly useless.

 

[GeneralDisorder]

not real familiar with the M1078 A1R or A1Rp2 to know if that trans key pad came from one of them or not. It is NOT from an A0 or even an early A1 if I recall right. Never seen that one actually. Others will chime in soon.

Model's are A1(R) and A1P2 - actually the military doesn't officially recognize the "A1R" - it's just a late model A1 in terms of the EMS-NG system - but some documentation including PS Magazine articles and some of the schematics mention it so it's kinda stuck. A1P2 is the "phase 2" which are all LTAS (Long Term Armor Solution) cab trucks.

The wiring harness and key-pad are both WTEC-IV like my 2008 A1R. The latest A1P2's are WTEC-V.

 

[spoonbender]

ok.. so it is an MD3070. that is the original trans to the 3116... it mayyyy have got internal wire harness updated..... may not. See https://www.steelsoldiers.com/threads/md3070-vs-3700sp-allison-7speed-tranny-in-these-trucks.154061/

not real familiar with the M1078 A1R or A1Rp2 to know if that trans key pad came from one of them or not. It is NOT from an A0 or even an early A1 if I recall right. Never seen that one actually. Others will chime in soon.

PS- where are those pics hosted? IMHO move them to here since they are hosted elsewhere.. your thread can end up being very informative for someone in the future...... or complete JUNK since pics hosted elsewhere pretty much always go bye bye, rendering the info. in threads on a board like this mostly useless.

Cool - thanks for the info. I'll have to see if I can check the serial numbers for compatibility ... somewhere(?). Obviously, the C7 has a ECU, so perhaps that was the reason for the overhaul replacements (still not clear why all things were replaced, but I digress ...)???

And not sure on the pic hosting - I attached to the post here, and the links on my side say steelsoldiers.com - what are you seeing?

 

[spoonbender]

Writing up an update on some research - just incase anyone is reading along - or has ideas.

Dug through the pile of parts and found the old 2 transmission controllers (pic attached), as well as the selector (WTEC III by the look of it). (Please let me know if I'm not attaching pics for a long-lasting forum post!).

And forgot about the other extras - circuit board PDP - AND the entire Cab wiring harness (with WTEC III connectors). Didn't notice either until today - the door latches are 'down', and there are led lights on the exterior - must have been part of the overhaul.

I have the pin outs from the WTEC III bulkhead schematics, so what goes to where after the bulkhead, but so far - have not found the 3700sp bulkhead (trying to confirm they are the same...). And based on the manual - there's a section on the TransID (TID) that says a 3000 series controller "should" work with the "3000 series transmission". I'm planning to reach out to Allison to confirm

Also will look into the dashboard lights thing (what ever is the official name... pic attached of the label) - as I suspect it functions off the CAN bus, and currently goes into 'diag' mode. Also, diag port registers nothing with a reader, so - definitely CAN bus issues. Any suggestions on how to diag CAN bus issues welcome(!), and with no schematics - I'm not sure where the termination on the chain is supposed to be...

Hopefully will warm up more, so I can dig in and start tracing wires.


Thanks for reading!

 

[coachgeo]

Wonder if that truck was a test bed truck. hence why so many variations of parts included.

 

[GeneralDisorder]

There are two termination resistors - one is near the engine ECM, and the other is below the dash on the passenger side. They are 3-pin Deutsch termination resistor connectors:

DEUTSCH DT06-3S-P006 J1939 CAN Bus Terminating Resistor

PRODUCT DESCRIPTION DEUTSCH DT Series 3-Pin J1939 CAN Bus Terminating Resistor Deutsch #: DT06-3S-P006 Brand: Deutsch Manufacturer: TE Connectivity Country of Origin: USA

mypartsuniverse.com

The idiot light panel runs off the MMDC (Medallion Marine Data Concentrator) that controls all the other gauges. If it loses it's connection to the MMDC (it's on it's own CAN network - not part of the J1939/J1708 ) the lights will go into a chase sequence.

A1R schematics are here:

https://ia802200.us.archive.org/2/items/fmtv-schematics-a-0-a-1-r/FMTV%20Schematics%20A0%20-%20A1R.pdf

 

[spoonbender]

Update - progress and a setback ...

CAN bus is terminated properly, and got some data from the j1587 (I think - reader did not complain it couldn't connect, just said 'no events') - so believe things are talking on the slow bus. No connection yet on the j1939, will have to chase the wires down for that (which are easier to see in the bundles with the colors).

However, trying to get the light display to function somewhat (fix the chase), using the handy schematics, I discovered the MMDC is missing. So, not sure what my options on that are, as I suspect they are hard to come by. Does anyone have a part number or anything to search on? Searching Medallion MMDC brought up a few hits on ebay (that appear to have the correct pinout/connectors), but they are asking quite a bit for it.

Otherwise, chased a few more wires on the engine ECM, and got the engine serial number (just incase I need to re-flash the ECM...). Slow progress indeed...

Thanks for reading!

 

[GeneralDisorder]

Beware the MMDC's you see on ebay - most are for boats and don't have the correct programming nor the air tank transducer fittings. I've scored a few for spares and all of them have had one or both of the pressure transducers inoperative just like my original so I sourced replacement transducers and repaired them. I also installed desiccant filters inline with the transducers to keep them clean.

J1708 / J1587 don't use or require termination so installing the termination resistors in the J1939 wouldn't have any effect on that bus working or not working.

 

[spoonbender]

Beware the MMDC's you see on ebay - most are for boats and don't have the correct programming nor the air tank transducer fittings. I've scored a few for spares and all of them have had one or both of the pressure transducers inoperative just like my original so I sourced replacement transducers and repaired them. I also installed desiccant filters inline with the transducers to keep them clean.

J1708 / J1587 don't use or require termination so installing the termination resistors in the J1939 wouldn't have any effect on that bus working or not working.

Is there a part number from any you have? Otherwise, I can dig into the TM's to find it - just curious if you have it handy.

(And yes, learning more on the J1939 and J1587/J1708 bus functionality. Termination is there for the J1939, but still no messages, so something is still not quite right. The MMDC shouldn't have any impact on it, so need to track power and bus lines still.)

Thanks!

 

[spoonbender]

Think I found it - new MMDC for sale here:

Ross Equipment, Inc. - 7020-20044-01

Even labeled “FMTV” … and not cheap.

Can anyone confirm?

(Annunciator is available there as well…)

Thx!

 

[GeneralDisorder]

Yeah that looks like the right one and about the right price. I show the price to the government in 2020 was $760.94 from Medallion Instrumentation Systems LLC.

Part numbers:

12423156, 12423256-001, 7020-20032-01, 7020-20044-01

NSN:

5895-01-591-7887

There is an updated box called out for Gen V transmission applications (A1P2's) but PS Magazine says it can be used on Gen IV or Gen V trucks:

5895-01-649-8229

Part numbers:

12423156, 12423256-002, 7020-20044-01

The updated part is cheaper - $558.36 and was introduced in 2015. I wonder if it addressed any of the issues with the transducers

 

[spoonbender]

Yeah that looks like the right one and about the right price. I show the price to the government in 2020 was $760.94 from Medallion Instrumentation Systems LLC.

Part numbers:

12423156, 12423256-001, 7020-20032-01, 7020-20044-01

NSN:

5895-01-591-7887

There is an updated box called out for Gen V transmission applications (A1P2's) but PS Magazine says it can be used on Gen IV or Gen V trucks:

5895-01-649-8229

Part numbers:

12423156, 12423256-002, 7020-20044-01

The updated part is cheaper - $558.36 and was introduced in 2015. I wonder if it addressed any of the issues with the transducers

Thanks for the confirmation! - now to see if I can order one. Will try Ross first, and maybe Medallion directly if need be...

Thx!