97 Saf-T-Liner No Start, No Crank

[Crazy]

Do you have ignition switches in the back near the engine? Have you tried starting from back there?

 

[BlackJohn]

hey Beau..do some googling on 1997 Sat T liner and read any manuals etc. They say damage can occur if bus is parked for long without battery being disconnected.
Also, about your transmission problem. I don't know the starting procedure for your bus but seems like the paek brake must be set and foot brake applied before the tranny module will activate and reset.

look for an article by John Whelan, schoolbus mechanic. I think he describes your problem to a T. Corrosion on a harness splice halfway back on the frame somewhere. Worth a read. This guy is good!

Anyway, I would start by disconnecting batteries before attempting anything. Start taking a look at all ground connections first on the whole bus. Clean them up, you'll be glad you did later. do you know how to use an ohm-meter for proving continuity? Best thing you can learn then you know what's good and how the circuit is built to work.

Get the right tools for the job, say a 1/4" socket set, a dremel tool and abrasive discs for cleaning with it, a real time saver. An angle grinder for those rusty frame connections to ground, block, starter etc. Coveralls and something comfortable to put on the ground so you can slide under the bus to work and layout you tools. Trouble/work light to see what you are looking at helps.
Persistence and patience and you will solve this and learn so much more about your bus.
Like I've read elsewhere here, if you can't fix it yourself, you shouldn't be driving it...unless you are made of money.

 

[Beau Medlar]

The mechanic yesterday didn't do much. He was hesitant for it being a Thomas. He did run me through a few things but didn't know where to start. He didn't want to mess with the starter. His advice was, if it clicks when you try to start, look somewhere else. Is this good advice lol?

I did as thorough a check as I could for grounding issues. Every ground I found was visually good. I can't find anything visually wrong. However, there is a lot to go through. I still cannot find this infamous but splice in the power wiring going to the VIM/ECU

So. This morning I had my wife try starting it while I listened for the click of the starter. It does in fact click each time she turned the key.

We then tried to start the bus from the rear. Key turned to "ON", held down my hatch button and pushed the START button as directed... ZILCH.

I did manage to find my Vandalock relay and have confirmed that it is now properly bypassed by other Thomas bus owners and as directed by two Thomas bus mechanics.

As much as I'd like to get it started, I am being told by Thomas mechanics to FIRST remedy my Shifter Display. Even if I did get it started by hotwiring it or by finding and fixing the no start problem, I still can't drive it as the transmission will not be operable.

However, I'm hoping that I can narrow my no start issue by not getting it to start from the rear, and hearing the starter click.

Please excuse my ignorance as I'm pretty much new to all of this and find it a bit overwhelming.


So far, I know this:

1)The ECU is getting proper voltage
2)My Vandalock system is now bypassed
3)the starter clicks when key is turned
4)Bus will not start from the rear
5)The Shifter display is blank
6)No blown fuses in the VIM or 'Back Box' (where the rear start button and battery shut off switch is located

Thanks for the help and patience everyone.

 

[BlackJohn]

Ok before we go any further on this. You need to undo the ground connections and clean the connector and the steel frame so they are shiny metal and put back together with new bolts, washers (flat and lock) and nuts unless you clean them shiny also.
Then start at your batteries and do the same to the terminals and connectors, both +ve and -ve. Follow the positive cable out to any and all junction points and clean them up to new condition. I mean all including feeds to fuse panels and anywhere else you can follow. If you don't you will never know what your problems are. It is an elimination process, hardly a quick fix.
Most buses have a starting sequence if diesel which makes me wonder if you heard the fuel solenoid and not the starter click sound. Did you actually have your hand on the starter solenoid and feel it try to work?
Yours may not have that butt splice mentioned but you really have to follow all the wiring and get to know what's what. How far from the start batteries to the starter? Charge batteries up good and try to start after you get your cleaning done then we will talk.
Good luck, should take you a good full week to do what I recommend. Visual tells you little.

 

[somewhereinusa]

You are going to have to either pay someone to fix it or learn to do it yourself. You have gotten some good advise and apparently chosen to ignore it. Get a good test light, wiring diagrams and learn to use them. You have a click, so what? When you hear the click is there power being supplied to the large terminal on the starter? Not the one that is hot all of the time, the other one. Since you're problems all started at the same time, I would suspect a bad connection. You can't"look"at them. You have to take them apart and PROPERLY clean them. Start at the battery cables, BOTH ends.

 

[Crazy]

The mechanic yesterday didn't do much. He was hesitant for it being a Thomas. He did run me through a few things but didn't know where to start. He didn't want to mess with the starter. His advice was, if it clicks when you try to start, look somewhere else. Is this good advice lol?

I have already stated that I am not a mechanic but apparently neither is your mechanic.

 

[family wagon]

I have already stated that I am not a mechanic but apparently neither is your mechanic.

That's kinda funny. :biggrin:

As BlackJohn mentioned, make sure the click is really the starter and not some other solenoid in the bay.

I don't remember whether there have been other items mentioned that would indicate the ignition switch is working. For example, do the interior lights, blowers, or low air pressure alarm come on when the key is turned to the run position? (I ask because the engine and transmission computers are likely to use the run position to wake them up, and the transmission control pad not lighting might be caused by this) If these all work OK, then things such as battery posts, connection to frame ground, etc may be fine. ("may be" because they could be good enough for these loads, but not for turning a starter motor)

 

[Dragonpop]

Lets start from square one, when you had the battery disconnected
did you undue both cables? Is there a possibility that the cables were
switched when they were reattached. This would make the electronic
trans control not function. Look at the battery and see if the - terminal
is attached to the ground or frame.

 

[GreyEagle-SKO]

Voltage at the batteries is at 12.6V. Bus is in neutral. This tranny doesn't have a neutral safety switch, but instead a relay (in the VIM) that checks out as functional.

I haven't checked anything else (starter,solenoid, etc) yet. I do have someone sending me information tommorow on my safety system so I can disconnect it (this is a possible problem). I know it's going to be one of those "duh" moments when I find the issue.

I'm kind of curious why the mechanics didn't check this stuff out. This so is not my expertise, but I'm doing better with time and experience.

PS I am no expert....... and
I don't know a lot about buses , but...... I did own a 40 ft diesel pusher motorhome that quit on me. I had my batteries tested at a O'Rileys Auto Parts store, batteries tested good 12.6 volts ..... as yours did with the 12.6 VDC.

I even have the batteries, alternator, checked by a so called mechanic at a shop in ??? the middle of nowhere, OK . I have CRS now and can't remember sh-t...... 12.6 volts, no problem, looks good he says. Only after calling a friend who was a mechanic in Tennessee, (I was broke down in Oklahoma) as soon as I told him the voltage was 12.6 volts he told me I needed new batteries. I replaced the batteries with 3ea - 12 VDC deep cycle batteries and the motorhome fired right up.
It wasn't until I got home that I realized that I still had a problem as the motorhome would not start again. Long story short turned out I had a short in the wiring harness just as it passed thru the firewall from the engine compartment.
I found this after 3 weekends of trouble shooting that monster (not to mention I had no ideal WTF I was doing) but I found it with the help of a short finder, again a tool that I borrowed from my mechanic friend. It sure is good to have friends in low places... LOL According to my mechanic friend (who has since passed) you need to have at least 13.5 volts or higher when you are testing you batteries. Sure hope this helps...
It sure was a big help to me....
Best of luck with your bus.

GE
Roll-On

 

[Crazy]

Holy cow, look who rolled in. Glad you're still around.

I don't think you will get 13.5 from batteries at rest. Maybe while on a charger or with the engine running.

 

[GreyEagle-SKO]

Holy cow, look who rolled in. Glad you're still around.

I don't think you will get 13.5 from batteries at rest. Maybe while on a charger or with the engine running.

Just passing on what my mechanic said...... It worked for my motorhome...
Cummins 350 diesel, Alison 3060 trans.!!!

 

[Beau Medlar]

Finally, an update.

Thanks again for the help folks... and apologies for my lack of communication and understanding what I was asking help for. I ended up finding the problem recently. Here’s a long story as short as possible:


So... over the course of my inherent ignorance with my problem, I managed to figure things out. Life got busy, as it does, and I had a total of 4 mechanics look at my bus over the course of trying to find (and thus fix) my problem. After a lot of conflicting information and mechanics giving up on finding the problem and getting confused about what to do (ASE certified master techs… BTW), I decided to learn what the **** to do. I basically learned what I needed to know myself from the very beginning, and that was to understand a starter circuit. In the end, it was very simple. And, I found my problem easily enough.

The thing is, I went through many mechanics. It turns out that my original mechanic switched the power wires that feed the ECU/VIM. This is what created the blank shifter display. I also found a lot of cut wires after that first mechanic (which the second mechanic found and fixed).

I was able to determine myself through checking the wiring harness that the power going directly to the VIM was coming in from the battery negative wire, and nothing from the positive side. My mechanics thought they found proper ground and power to the VIM, but failed to realize they were coming in INCORRECTLY through the harness. They thought the ECU was bad, or the circuit board in the VIM was bad... they blamed bad relays, etc.

So. I switched the wires to properly send power to the VIM... and VOILA.. I got my shifter to respond and my transmission is now working. However, I still had the original no start, no crank problem that started all of this.

A few minutes of checking the circuit in the back PDU box determined that I had a loose connection on the starter relay. Less than 15 minutes of work… and my bus is working perfectly now.

So, in the end, I learned like many do... through trial and error. I'm still stumped on how 4 mechanics could overlook the obvious. However, 2 of them were giving me estimates of $4000 or more to repair the bus... so perhaps they had a motive to NOT find the problem?

Who knows, but we are rolling again.

 

[Rameses-SKO]

There's a big difference between a mechanic and a parts changer.

You weren't dealing with mechanics.

 

[Shadowfax]

I know this is old but this thread really helped me out. I have a 2002 Thomas mvp ef and was able to get my bus started in about 10 minutes after reading through. This should be stickied.

Thank you OP!!!

 

[david.dgeorge07]

I’ve experienced similar issues. Never go with the $4k fix when you haven’t gotten to the bottom of the more simple stuff. Glad the OP got it worked out.