After test driving my coach now a few times, I noticed that the engine can be started with the transmission lever in gear. (MC9 , 5spd. auto). Probably not a good thing.
I just had the tranny serviced at an Allison shop, (another question on this will come later) and they said that the neutral start switch was functioning as it should so the problem was elsewhere.
Any thoughts on how to trace the problem?
Thanks, Iver.
If I understand from talking to the man at the allison shop yesterday mine is operated off of a relay. The switch in the transmission is a ground that gives the relay a ground to close the connection to the relay to send the power on to the starting system.
If that is the case the wire coning from the transmission could be bare and causing a ground on the frame or some thing.
That is if you can start it in any position.
I could be wrong I am just trying to figure out this on mine myself. That is how to wire it, mine does not have a working neutral safety switch on it either, I am trying to get one wired the reason I was talking to the man in the first place.
I spoke to a bus mechanic today and he said the starters in these coaches had a built in switch that would de-activate the starter when the transmission shifter was in gear. My starter is not the original so it apparently does not have one.
Not sure if he is correct but could be....
Iver.
Iver, I do not think he meant it was in the starter itself. You need to find a wiring diagram for this. Allison says its good at the trany, that should be a N.O. contact. ( normally open) So in neutral it closes. I'll try to look at my 5c book. Tom Y
Iver, Mine shows a neutral relay in the rear junction box. It shows it as the top relay. Like Bob said it makes a ground thru the trany. This is a 5C should be the same as the early 9s. If you need I can copy and fax or email the diagram. I would look to see if someone bypassed the relay. Tom Y
Thanks Tom,
My book shows the switch on the tranny as well. (normally open). I understand it goes to a relay but then where?
My guess would be that the transmission switch would have to be in neutral to close the circuit so that power can go to the starter solenoid and engage the starter. I guess I'll have to try to trace the wires....
Iver.
Hope this helps. Tom Y
Just changed me trans neutral switch. 5C located on the curb side, just above the linkages, may be different on the 9. Easy to do, just jack & block high enuff to keep fluid within trans.
My switch was intermittent. It too was a switch to ground, powering a relay to enable the start circuit.
Good Luck
Gary P