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56corvette · 07-27-2014, 07:45 PM

This my first attempt at asking question here and hope i'm in the right area. In an 03 windsor with 370 cummins, my exhaust brake works intermittently. Sometimes half day, sometimes 10minutes. Connected air hose directly to brake and butterfly works smoothly. Solenoid and air cylinder check out ok. Next i'm checking the omron relays up front. Anyone have this issue to deal with? Appreciate the help. By the way, cummins and allison just blame it on Monaco and being an 03 there's not much help.

Gorlininc · 07-27-2014, 07:50 PM

My exhaust brake was intermittent. I changed the relays in the bay up front. Didn't fix it.
It ended up being the switch on the dash was intermittent. I changed it out as a last resort and my problem went away.

Skip426 · 07-27-2014, 07:53 PM

Your question came through just fine .
Does your shifter pad display second gear when the exhaust brake is operating and when it doesn't ?

56corvette · 07-27-2014, 08:05 PM

Thanks for the quick response. Shift screen shows downshifting to 2nd when brake is working and no change when brake is not working. I will check the switch but being only single stage brake, I thought switch was just on or off but will check that out.

Gorlininc · 07-27-2014, 10:40 PM

It is only an on/off switch. Bit I guess my contacts went bad and were intermittent. I'd say if it's not going into second gear when the switch is on. Then it's probably the switch. The nice thing is should be a cheap easy fix. Let us know.

56corvette · 07-29-2014, 06:42 PM

To those who offered help, many thanks. Here's what happened. Swapped out relays and was about to test drive when "warning" light came on. Now it's been doing this for sometime and as soon as the accelerator is barely touched it goes out. Well for some reason, I reached down and unplugged the multiwire plug that is in front of brake pedal and plugged it back in. The warning light never came back on and after driving about 30 miles and activating the exhaust brake maybe 40 times, it never missed a beat. I won't be sure it's ok until a longer trip but seems ok, but I don't know if the relay or the plug in and out corrected it but I'll take. Thanks again!

Skip426 · 07-29-2014, 10:34 PM

Probably the plug , the ECM wants to see zero signal from the Throttle Position Sensor; TPS should be on the back of the throttle pedal, and it's wiring may be part of that connector; before allowing exhaust brake operation. So any , fuzzy , signal would stop operation.
JMHO: pull the connector apart again and use a contact cleaner spray to insure good connection.
Also check the pedal hinge for rust , particularly is there is carpet around the pedal. Carpet cleaning can raise havoc.

EDIT: A second thought, Cummins uses a redundant, double TPS, your light was probably coming on because the ECM , was loosing signal from 1/2 the TPS.