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Old 04-21-2019, 06:58 PM   #1
Join Date: Oct 2010
Posts: 54
Neutral Safety 2007 Newmar with isl400 and 4000 Allison

Good Evening Gents,

Looking for some advice and direction where to go next. I have a no start issue with my 2007 Newmar Dutch Star. It has a 400Cummins ISL and 4000 Series Allsion. I have narrowed it down to an issue with the neutral saftey relay circuit which when energized then pulls in the starter lockout relay. There is no issue with the keypad and showing neutral. I can jump the starter relay and the coach runs with no issues, transmission shifts as normal. The 12V signal to the neutral start relay that is supposed to pull the relay in has no constant voltage. It jumps all over. I have verified ground to battery and continuity is good. I cant figured out where the 12v signal comes from. It appears direct from Transmission ECM which leads me to believe the ECM has failed?


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Old 04-21-2019, 10:13 PM   #2
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Join Date: Apr 2011
Location: Powell River, B.C.
Posts: 19,642
Issue could be with the wiring or controls in a wiring/fuse/relay module at the rear of the coach .
Is your coach on a Freightliner or Spartan chassis ?

Either company could provide wiring schematics for your chassis .

Is the neutral relay you're testing in a module like the one pictured below?
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99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
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Old 04-22-2019, 11:59 AM   #3
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Location: Sarasota, FL
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If you think it is the TCM, call John at Transmission Instruments - this guy knows TCM/ECMs and talk to him. After talking to him, I sent my TCM to him, he jumped right on it and emailed me to tell me there was nothing wrong with it. I called him and we talked for quite a while and he then sent a wiring addendum that fixed my problem. Since there was no problem found it only cost me shipping both ways.
Rick and Larrie Dee
1997 40' Newmar London Aire DP CTA 8.3 (Mechanical) 325 Spartan MM
Bringing her back to her glory.
'08 Jeep GC Overland.
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Old 04-22-2019, 06:03 PM   #4
Join Date: Oct 2010
Posts: 54

Hey Skip thanks for reply. Yes my box is similar but probabaly twice the size with double the amount of relays and fuses. It's on a Spartan Chassis and I have the wiring diagram. I can't figure out where the transmission ECM gets the neutral signal. I have pulled the Neutral signal relay and checked per wiring diagram. The neutral signal which should be 12v with iginiton on is not a constant voltage so it won't pull relay in. The voltage jumps all over.


Thanks for advice, I will reach out to him for some advice.

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allison, newmar, safety

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