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dnash
New Member
8 Posts |
 Posted - 06/26/2019 : 11:19:19 AM
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| Maybe you could help me trouble shoot this . It’s a 2009 Blue Bird was brought in for a PM and found it has no brake lights, checked all wires, both air act brake switches were bench tested and are good and fuse and relay are good. I have no power from the BCM to the signal side of the relay when the brake is applied. I can bypass the signal wire to hot and the lights come on. So all wires from the relay to the lights is ok. When brake pedal is pushed I have power thru the air switch to the BCM. But no power comes out of the BMC to the relay. I replaced this BCM less then a year ago, but have checked everything else I could think of. Seams like it should be a very simple fix, switch, power light, but its kicking my B-HIND. Tried to move bus forward in the shop and now I get a range interrupt single and the bus will not go into gear. I don’t know for sure but I would think that the Range interrupt and the brake light signal work off the same switch(gate) Only thing I don’t know is how to verify the BCM is doing its thing. Any thoughts? |
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eshover
Senior Member
146 Posts |
Posted - 06/27/2019 : 07:32:58 AM
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WE had one newer than this that had a relay problem. Changed relay and worked OK. It did not have any brake lights and would not shift as you said.It almost has to be the brake light relay.On out latest bus it's R36 in the electrical locker.
ED |
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dnash
New Member
8 Posts |
Posted - 06/27/2019 : 11:08:20 AM
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quote:
Originally posted by eshover
WE had one newer than this that had a relay problem. Changed relay and worked OK. It did not have any brake lights and would not shift as you said.It almost has to be the brake light relay.On out latest bus it's R36 in the electrical locker.
ED
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dnash
New Member
8 Posts |
Posted - 06/27/2019 : 11:18:30 AM
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| Thanks eshover, Ya that's what I was thinking as well, the relay checks out good, but I have no power from the PDM to the relay on the AA-109A wire. when the brake is applied. I can bypass the relay and get brake lights. but still get a range inhibit light and no shift out of neutral. Im thinking the problem is in the PDM. I have a sister bus with the same PDM I will switch it out and hope this fixes the problem. ill let you know. |
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WrenchMonkeyCSISD
Active Member
USA
30 Posts |
Posted - 06/28/2019 : 05:04:18 AM
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| If it's anything like the newer IC's you can have proper brake activation and function, but the actuation signal might be missing. That will throw the range inhibit warning and deny shift from neutral. I'm not familiar with BB so I couldn't tell you if everything comes from the BCM or if there is a sensor on the treadle valve. But it might be a good place to start. |
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dnash
New Member
8 Posts |
Posted - 11/01/2019 : 11:36:07 AM
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| Just a heads up. It was a faulty BCM. $800 bucks later I have brake lights again. #$$#@#$ $800 for a brake light switch......... |
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bwest
Administrator
United States
3820 Posts |
Posted - 11/01/2019 : 12:14:17 PM
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quote:
Originally posted by dnash
Just a heads up. It was a faulty BCM. $800 bucks later I have brake lights again. #$$#@#$ $800 for a brake light switch.........
Why didn't you bypass the circuit? |
Bryan |
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blue bird brake light
