Community Forums

rail2841road · 05-14-2020, 07:49 PM

My key pad for the Allison transmission has no power. 1999 Holiday Rambler 38'

Where does the pad get its power and where should I look for fuse or relay which must be dead?

8.3Oilbuner · 05-14-2020, 09:42 PM

Good evening Rail2841road; Kind of going to be a generic answer as coaches change from year to year. There is usually a hot wire off the chassis battery that supplies power to the Allison key pad. This subject comes up quite often. Others here have found an inline fuse in that hot wire from the chassis battery. Can be close to the battery or up the line in the harness. You might have to trace up the line to see if there is an inline fuse. Also others have had a bad connection at the plug on the underside of the shift pad itself. Check the plug for a good seat into the shift pad and also might need to clean the connection. Are you getting other dash items that run off the chassis battery working? Just curious. Hope this info helps and you get power back to the shift pad. I am sure others here will respond shortly.

mb2875 · 05-15-2020, 08:36 AM

Not sure if it is the same problem but a few months ago on our annual trip to Florida my unit suddenly quit in the middle lane on I95. Got it over to the side and everything having to do with the engine was dead. Ended up calling a roadside service and 2 hours later he found the problem. The symptoms sound a lot like yours. No trans pad light everything dead. Turns out there is a fuse at least in my MH in the outside panel below the drivers seat that has a circuit to ensure that you can't start your unit in gear. That fuse was blown. The under lying problem was the cord between the MH and my toad had loose connections. I found out the next day when the fuse blew again and I unhook the cord and the problem went away. Your cause may be different but the fuse being blown may be common.

jacwjames · 05-15-2020, 01:11 PM

Mine did the same thing in 2013. I took the coach for a drive in prep for a trip, parked in the street in front of the house to hook up the toad. Went to restart and the shift pad was dead. I checked as much as I could and ended having to have it towed and they replaced the ECM for the transmission, ~$3500. We were in a rush, could have sent the unit in for rebuild but didn't have time.

vito.a · 05-15-2020, 01:35 PM

On most of these coaches there is a direct wire from the battery to the Allison ECM. Usually there is an inline fuse in the battery box area.
One of the guys on here ran a new wire from the battery to the Allison ECM in the basement to troubleshoot his.
Hope you get it figured out.

rail2841road · 05-16-2020, 11:02 AM

Thanks. All comments aare aappreciated

rail2841road · 05-16-2020, 03:14 PM

Quote:

Originally Posted by rail2841road

Thanks. All comments aare aappreciated

I have replaced Three Fuses in the battery compartment. If the fuses were blown, could the ECM be damaged also. Can the ECM be removed by me or does it require a service technician and can they be repaired? Could one of the relays be damaged over and beyond the three fuses. I'm trying to sort out the best path or maybe sell it very cheep and stop worrying. I looks like it could be very expensive....? Thanks for all your help!!

vito.a · 05-16-2020, 03:30 PM

Yes. The Allison ECU as well as the keypad can be tested and if necessary repaired or reprogrammed.
It is not difficult to remove if you don't mind laying on your back in the basement. When working on any electronic component you must be careful of static electricity.

rail2841road · 05-18-2020, 07:58 PM

Quote:

Originally Posted by mb2875

Not sure if it is the same problem but a few months ago on our annual trip to Florida my unit suddenly quit in the middle lane on I95. Got it over to the side and everything having to do with the engine was dead. Ended up calling a roadside service and 2 hours later he found the problem. The symptoms sound a lot like yours. No trans pad light everything dead. Turns out there is a fuse at least in my MH in the outside panel below the drivers seat that has a circuit to ensure that you can't start your unit in gear. That fuse was blown. The under lying problem was the cord between the MH and my toad had loose connections. I found out the next day when the fuse blew again and I unhook the cord and the problem went away. Your cause may be different but the fuse being blown may be common.

I have checked and rechecked the fuses and relays, no luck. It sounds so simple but to me it is the most difficult problem. Does anyone have a wiring diagram for a 1999 freight liner chassis, even a hand drawn simple diagram would be very helpful.

rail2841road · 05-18-2020, 08:05 PM

Would you have a wiring diagram for freight liner chassis or know of someone or a hand sketch would be helpful.

Jeff753 · 05-19-2020, 07:50 AM

Quote:

Originally Posted by rail2841road

I have checked and rechecked the fuses and relays, no luck. It sounds so simple but to me it is the most difficult problem. Does anyone have a wiring diagram for a 1999 freight liner chassis, even a hand drawn simple diagram would be very helpful.

We have 6 devices wired directly to the battery. One is the ecm. Make sure your ground wires with these circuits are also attached to the batteries.
Mastertech installed some lifeline batteries for me a few years ago and crushed the ground wire for the ecm causing the key pad to go dark.

rail2841road · 05-19-2020, 07:59 AM

Quote:

Originally Posted by Jeff753

We have 6 devices wired directly to the battery. One is the ecm. Make sure your ground wires with these circuits are also attached to the batteries.
Mastertech installed some lifeline batteries for me a few years ago and crushed the ground wire for the ecm causing the key pad to go dark.

Thanks I will follow up on your advice.