2001 Thomas Saf-T-Liner

[MattSTL]

Hi, I have a rear engine safety liner that’s new to me. I replaced both engine batteries this morning due to a bad cell/loss of charge on the old set. Now the bus will not attempt to start.

There is a status light box above the breakers next to the engine, anyone know what the lights mean? The rer light is red so I’m going with that’s the current issue, but not sure what the light is for. Any takers?

Thanks in advance.

[Danjo]

New batteries?

Got a pic? We love pics!

Have you a multimeter?

[MattSTL]

Added pics of the old 8dsa batteries, the new ones are Deka brand 908DFT as I couldn’t get the 8dsa’s anywhere.

I did not test the batteries, silly me thought they’d be full. Are you thinking they’re not fully charged causing the start problem? I will say it does act the same as the front is all lit up and ready but nothing from the back….

[Danjo]

Originally Posted by MattSTL

Added pics of the old 8dsa batteries, the new ones are Deka brand 908DFT as I couldn’t get the 8dsa’s anywhere.

I did not test the batteries, silly me thought they’d be full. Are you thinking they’re not fully charged causing the start problem?

Don’t know. You’d assume brand new batteries would be fully charged. Just trying to check off the easy boxes

So it started and then it sat, the batteries went bad and it wouldn’t start so you replaced the batteries and it still won’t start?

Do you get power to other things, like lights, dash and the like?

In a case like this I’d say to check those cables, check the terminals on both ends, check all your ground cables and terminals. Make sure they are clean and bright and well connected.

Make sure those batteries have 13.5 volts.

[MattSTL]

It’s something to check and I probably should have but didn’t, also not a lot of time today, figured a quick battery swap, fire it up and get home to take care of some other stuff. It’s always something with these things!

[MattSTL]

And I have till spring to figure it out.

[MattSTL]

Yea I had driven it a few times to get it inspected, had a repair done, and just drove it around a bit to get used to driving it, never an issue until the second to last time, it has a backup camera that has to be disconnected or it will drain the battery, I forgot to disconnect it. I jumped it, started up fine, ran fine the rest of the day on/off multiple times. 2 weeks later started fine, then came back last week and they were below charge, unhooked and charged the one but the other one kept telling the charger it was bad, took it it and bad cell. Before all this not an issue starting.

I’ll get back down there week with my meter and check them out for voltage, I know it gets cranky even a little low.

I’ll check the cables as well. Thanks for the advice

[MattSTL]

And yes the dash is totally normal now that the new batteries are connected.

[ewo1]

It's a rear engine bus?

Is the front/rear start switch in the correct position?

[Danjo]

Oh yeah, considering it’s a bus, make sure all the hatches are securely closed

[jimmythomas]

That small red wire on the positive battery cable - it powers the engine control module. Make sure the fuse is good and the wire is actually sending power to the ECM.
And the transmission is in "N".
Good Luck!

[MattSTL]

I’ve been there done that with the transmission already so that was my first check!

Good to know on the wires, wasn’t sure on that and neither was the previous owner, thanks.

[nikitis]

There is likely more than just your backup camera draining your batteries. The ECM is always powered even when the bus is off and it will slow drain your batteries. This is why most skoolie owners like to add Battery Disconnect switches to our setups to ensure NOTHING can drain the batteries.

Normally the drain isn't an issue on buses because they are driving every day charging more than draining when driving kids to school, but your bus isn't doing that any more. It's rarely driving, and not charging enough so the drain is more than the charge.

I did this to my bus after replacing batteries. They wouldn't last 1 month if I didn't crank them or have the disconnect. Since the disconnect the bus runs and cranks every time and I check the batteries with multimeter from time to time to see the nice 12.7V's they came with still there even after a couple of weeks of no running it.

[Mat7783]

Make sure your rear engine control box has the power toggle on.can start engine from rear if you hold door closed button as a safety and push start button.