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Topic: Neutral light staying on when ignition is off  (Read 1593 times) previous topic - next topic

Re: Neutral light staying on when ignition is off

Reply #20 –
Update:
1. I installed the new transmission relay under the dash and the N light did not go out. 
2. I then tried replacing the N safety relay and light still on.
3. Moving along I then unplugged the computer power thru engine relay and the N light went out installed a new relay then the N light came back on.
4. Also I checked to see if the engine hour meter was operating with the key off and it wasn't then verified it was operational with the ignition on in case it was the oil pressure sending unit as was posted by John Fitz.

Thoughts on the next step?

Re: Neutral light staying on when ignition is off

Reply #21 –
Is there power all the time to the transmission selector?

Re: Neutral light staying on when ignition is off

Reply #22 –
So I exercised the transmisson shifter several times F N R etc. Now the light is off and is staying off.....

Re: Neutral light staying on when ignition is off

Reply #23 –
1997 model has a 30-amp circuit breaker in the bay wall 12v panel that feeds start battery (always hot) voltage to a 10-amp circuit breaker on front door 12v panel, which then feeds the Allison computer.

The computer then sends this voltage to a "Neutral-Safety" Bosch-type relay coil on front door 12v panel when the transmission is in neutral.

The above is used to pass ignition switch start position voltage through "Neutral-Safety" relay to Aux Start solenoid on isolator panel. See attached Starter Wiring Circuit for details.

Re: Neutral light staying on when ignition is off

Reply #24 –
But, totally different transmissions between the 1993 U300 and any with the Allison 3000 or 4000 series,.

Re: Neutral light staying on when ignition is off

Reply #25 –
Quote from: leejrfla –
So I exercised the transmisson shifter several times F N R etc. Now the light is off and is staying off.....
Excellent!  ^.^d  Suggest you start and then move coach forward and backwards, turn the key off and then check the light.

Pierce

Re: Neutral light staying on when ignition is off

Reply #26 –
The Transmission is an Allison HT 746

Re: Neutral light staying on when ignition is off

Reply #27 –
So the N light is back on.  I am going to have the oil pressure sending unit replaced as Fitz mentioned in his post and we shall see if that works. It doesn't take long for this issue to run the battery down.

Woodie
 

Re: Neutral light staying on when ignition is off

Reply #28 –
Quote from: leejrfla –
1. I removed the 5 amp aux trans control fuse N light went out.
In the photo you posted in Reply #13, what is that silver object?  Looks like it is located near the aux trans control fuse?