Retarder Not Engaging

Lostranger · September 27, 2014, 06:31:22 AM

Due to the state of the conversion, we've not used the bus much in several months. Now I'm driving it often, and we'll be on the road all the month of October.

I've discovered that the retarder is not engaging. First noticed that stopping felt different, then I looked up at the light panel above the windshield and saw that the retarder light is not coming on when I brake.

Bus is '99 Gillig. Multiplex wiring. Allison B400R coupled to DD series 40.

I've not found any breakers tripped. I have the wiring manual, but I've not had time to troubleshoot. Looking for obvious places to begin.

TIA

Jim

luvrbus · September 27, 2014, 11:12:20 AM

If your stop lights are not working the retarder will not engage on most vehicles I don't know about yours

LuckyChow · September 27, 2014, 12:07:10 PM

Jim, check the wiring diagram to locate the breaker that supplies power to it. If you had a high floor Phantom, I could tell you where it is, but I don't know on the low floor. Most properties also specified a toggle switch that could be used to turn it on and off. The location of these were all over the board. The most common areas I've seen are at the rear control panel in the engine compartment and some in the overhead destination sign compartment.

If all else fails, I can give you the name and phone number of a person in their engineering department.

blue_goose · September 27, 2014, 12:12:54 PM

ON THE LOW FLOOR ONE'S THE RETARDER SWITCH IS AT THE REAR OF THE PANEL BY THE DRIVER'S WINDOW. THE RETARDER DOSN'T COME ON UNTIL YOU APPLY THE BRAKES.
JACK

Lostranger · September 28, 2014, 03:58:09 AM

Thanks to everyone to weighing in. My primary control switch on the dash is on. The toggle switch on the large sub panel at the r/r of the bus is on. I don't know yet which breaker is involved, but none are tripped or off. I will check the wiring manual so I can test that circuit for power.

Darryl, I would appreciate having that phone number. Gillig has been most helpful the few times I've called about parts or service issues.

Even without the retarder, this bus stops well. When it's working, I feel more confident about stopping than I have in anything I've driven. This is my first experience with a retarder.

Jim

Lostranger · September 28, 2014, 04:31:46 AM

Forgot to mention that the stop lights are working.

LuckyChow · September 28, 2014, 04:56:26 PM

Jim, I sent you an email with the info.

I suspect your retarder is the same as mine, since we have the same transmission and the buses are only one year apart. I know some of the later B-400's had a different retarder, but don't ask me how it was different. A transmission guy told me this. Mine originally came with a disable switch in the rear engine control box. There was nothing inside to turn it off. The original purchasers didn't want the drivers turning them off. Mine is switched on and off by a pair of relays in the front electrical panel. I added a switch from there on the inside of my bus so I can turn it on and off easily from the drivers seat. Even though you have multiplexers, this function might still be controlled by the old fashioned relays. Check and see if you can find the control circuit and see if it goes to a multiplexer or relays. You might just have a bad relay or no power to it.

Lostranger · September 28, 2014, 07:25:52 PM

Darryl, I can't thank you enough. This week is already a marathon of bus work, but I might get to troubleshoot that circuit sometime before the weekend. I'll report when I do.