On a recent trip back from Colorado, the retarder in our 97 U295 stopped working, or at least the lighted switch stopped working. We were already in Texas so it wasn't really needed by then. When home, I checked the relay which appears to be working.
I pushed both arrow buttons on the shifter panel and I got what I believe to be codes, but could not locate those in the Foretravel manual. The first one to show up was: 7 0, followed by 0 L, followed by - -. Like I said, I couldn't find anything in the manual and don't know if they mean anything. I have never checked the codes before so they could have been in there for a while.
OL is oil level. I believe you need the engine running and transmission up to temperature to get the proper reading (7-0 indicates sump temperature is too low).
The full error code listing is in the Transmission section of the wiki Allison Transmission (https://wiki.foreforums.com/doku.php?id=technical:transmission:start) Start with page 19 for the WTEC III era coaches.
Search on the Forum for the terms "retarder solenoid" and "retarder accumulator". These items have often been the cause of retarder problems.
To access the Allison diagnostic codes:
Ignition on/engine off.
Push up and down arrows at the same time. That will bring up O L for oil level.
Push the up and down arrows again at the same time. that will bring up d-1. If there is a stored diagnostic code, it will show the code.
If there is a code, record it and push the mode button to bring up d-2. Continue until you get d-"whatever" and - -.
Turn off the ignition to return to regular shift pad use.
Brett,
No codes were stored.
Switch light bulb burned out? Voltage at switch terminal? Could retarder be working without light on? Retarder can work with brake pedal lightly pressed. Wire fall off bottom of retarder switch?
Easy to confirm if the retarder is working. Pull lever all the way back, lift throttle, coach will almost come to a complete stop with no brakes.
If you're not sure , take it out for a test drive, as Geodmann stated use the retarder lever in the full activation position after letting off the throttle, then you will know if its not working or just a defective lamp. Let us know what you determine.
He may just have the switch and no joystick,let's get that verified.
Coach has both switch and joystick. I never realized that there was a light on the switch, guess I am too busy paying attention to what is ahead of me then looking at the switch.
On my 95 U240 the retarder works by light touch on brake pedal. The retarder switch on dash does have a light and comes on when retarder is used. The switch on dash is used to disable the retarder. I use the switch when I am running hot on engine temp. I have to drive like old truckers in high ambient temps, don't use retarder, going up and down hills in same gear, using gears to control speeds entering towns. i love the retarder, but it does increase trans and engine temps when in use.
Pat
We put a small LED on dash so driver can know when retarder is activated. Wired it from the side-dash. Very helpful LED.