1995 Tiffin

[Bellbass]

I have a 1995 Tiffin allegro bus and am having some issues. When I turn the key to start sometimes it would start and sometimes it would not. Taken it to two different shops to look at it. They said they couldn’t get it to not do right. This morning I’m trying to take it to the shop and I turn the key on and wait for the wait to start engine light to go off and when it goes off I get nothing. I got the 3 or four lights on dash but nothing on the transmission selector. So I try and try and still nothing. So I turned the key and it started it before the wait to start light went off and it cranked. But I have the Do Not Shift light on on the dash. My Allison transmission selector has not shown any life at all this morning. It won’t shift . I’ve cut it off and tried to crank by waiting until the wait to start light goes off and I get nothing. I turn it and crank without waiting for the light to go off and it cranks.... I’m horrible mechanic....I did undo positive battlers cable but nothing changed. Any advice would be appreciated!

[UTTransplant]

Do you have a 12 v full off switch somewhere (aka “salesman’s switch”)? On newer units, cycling that can reset things. Don’t know if it will work on yours, but you could try it.

[Biljol]

If your transmission ecu has no power it will not allow you to start.

Might want to make sure you have power to the ecu for the transmission

[deandec]

I have a 1995 Cummins 300hp engine, but the electric stuff was done by Country Coach.

The rig has a Chassis 12v Fuse Box in the front driver side compartment. Yours may be elsewhere.

Attached near the fuse panel there may be an ignition solenoid with four wires.

https://www.oreillyauto.com/detail/b...ufacturer=true

A wire from one of the small terminals is the ground wire.

Clip a loose 16 gauge cheater wire to that terminal or wire and connect it to a good ground point. Then turn the ignition switch to on. Perhaps the Shifter will light up and the rig engine will crank.

Hopefully yours is similar and the fix is that simple.

[Gary RVRoamer]

I think you found the problem. If the engine cannot verify the transmission is in neutral, it won't even attempt to start. And if the shifter pad/handle is dead, there will be no "Neutral" status to signal. So now the question is why is it dead? Bad TCU, faulty relay, or simply a loose wire somewhere? I had a similar no-start that ended up being a poor wire connection on one of the Allison relays adjacent to the TCU.Not obviously bad, but just the right (wrong?) wiggle caused a no-start.

[153stars]

Many have found issue with 10 GA wire or corroded loop on positive chassis battery within a foot or so of the loop is an inline fuse holder it can get bad/loose as well.
Ignition switches have been prone to issues.