Starting issues

[BamaBus]

Originally Posted by TGase33

Hi again... got the video posted on youtube... heres the link. https://youtu.be/iMUFdiN1RSg

Still no starting or anything. I bought this about two weeks ago and it started up perfect no problems each time when i test drove it. I have done no work since then and went to start it and it wouldnt start. Not sure whats going on. Im now thinking a possible issue with the ignition switch. If anyone could have further input id appreciate it. I have no idea what to do. Thanks everyone so far for all the help. Could anyone second that the small gold box is indeed to do with the emergency exits and could i just disconnect it all?

There may be another fuse panel on the dash that has a 4x6 cover.
You haven't done any work but are connecting batteries. My Thomas has two batteries plus some extra wires and would be easy to connect wrong. That happened recently to another here. Could you post a picture of the batteries connected?

I would take kazetsukai up on any offer to help!

[kazetsukai]

Originally Posted by BamaBus

I would take kazetsukai up on any offer to help!

Really, the key is being methodical and patient-

I was able to help a local couple with their brake lights on their shorty by tracing wires. They removed the stop sign and when they did, they just allowed the wires to sit bare in the wall. Those were live, so when they touched the chassis a breaker upstream tripped.

There was lots of confusion as there are multiple fuse panels for the same thing and the lights in question tapped off of the "bus centric"/body fuse panel that Thomas added rather than the chassis' factory fuse panel from GMC.

I spent probably 2-3 hours following wires, measuring as I went along. Helpers to turn the keys in the ignition and/or hold a flashlight and Buddist-monk-level patience will probably help more than any specific advice I could give.


Good luck, OP.

[JackE]

My bus has a power cut off switch in the engine bay, it's a RE, so the cables from the battery go from them to the switch. If you have one of these, check connections there. They can be corroded enough to let low amperage current through, but not high amp like the starter. Next would be to test the power into and out of the ignition switch. If that is functioning, next thing I would do is to put the key in the run position and jump the starter relay to see if it will start and run.

I had a problem after removing some wires and did some voltage chasing and ended up finding the interlock relay for all the emergency crap and bypassing that so the bus always thinks everything is in the correct positions. Haven't had any start issues since.

[John 321]

If it started the last time you drove it and you have not made any changes to wiring, the problem is most likely the interlock system.

Suggest you open all the doors and then close them securely. Don’t latch them.

Try starting the bus

Good luck.

[bigskypc50]

Mine is a 94 Amtran, that buzzer sounds like it’s trying to tell you there is some door open. Also do you have a side emergency door? Mine has a small barrel lock at the bottom that has to be unlocked to shut that buzzer up you might have one at the rear door too

[bus-bro]

A wiring diagram and a volt meter would do wonders for you. The alarm would be low air pressure. Could be an interlock thing, bad grounds, low voltage, or component failure. And do you have a RE bus? That the front/rear switch could be set were you ain't.

Me, I love the clamp-on ammeter, DC. So much fun to know how many of those electrons are flowing. Without a diagram I would start at the batteries. Providing you have dash power. Clamp amp a battery cable and have someone try to start the engine, and see if you have current. Of course, you could take a voltage at the positive starter solenoid coil terminal to ground with someone turning the switch.

[John 321]

Mine is a 1996 Thomas Re.

I got a bit carried away during the demolition phase and cut a few too many wires. Bus would not start. Worked on the birds nest wiring scheme for a couple of weeks before I got her to start from both the front and back. The amount of wire I took out was impressive.

[John 321]

Btw I had 3, count em yes 3 solenoids that operate off the ignition key. The most important one makes its home under the air cleaner at the rear of the bus. Once I found that bugger and figured out how it got power, I was home free

[maddmaxx]

Do yourself a big favor and pick up a remote start switch at Harbor Freight. Then you should be able to bypass all the interlock circuitry and hopefully crank it over.

I saw two Relays at the first of your video see (pic below). Connect the starter button leads to the "Starter Relay" (Bridge opposing side terminals). The second relay in the pic is probably your interlock relay. It's worth trying to bridge it as well to try and isolate the issue.

On second glance it appears that the wires have been cut on the Relay at the bottom of the pic... That could be the problem.

[Ranchorossa]

Do any lights come on in the bus? Do any fans or blowers work? Do you have a battery shutoff switch? If you have absolutely no power in the bus, start working from the battery on out with a VOM. It's probably something simple that takes a lot of time and head scratching.

There are a lot of school bus mechanics looking for work right now. For $25 an hour, I'm sure he could find your problem quickly. And, have him spend an hour going over the bus with you. Look under the hood and have him explain what everything is under there. Go over the fuse box as electrical problems are common. After I started tearing out stuff, my bus wouldn't start either. Turns out that the camera equipment must be functional for the bus to start. Who knew?