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Allen Bradley system
My 2002 Liberty uses a controller called Allen Bradley which if not working will pretty well shut down the coach on the house side. If its faulted the coach cannot utilize AC from either shore power of the gen set. Also none of the normal switching inside the coach will work. A tech who works with the Allen Bradley CPU spent part of two days trying to solve the issue. What he found out was that the A.Bradley may have been fine but it saw a relay that was malfunctioning in that fifth module ( from left to right is the power supply far left , then the cpu which is counted as zero then the modules nine in number). The relay faulted the cpu which then killed almost all functions. I could still drive but that was about it.
It seems like a weak link to me to bet your coach life on a system like that. I just wonder if anyone else has had issues in this area? All coaches have to have a way to control functions . I am told the system is highly reliable. Just my bad luck it was 15 minutes before a 1500 mile trip.
Wave
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12 Replies
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I agree it seems like an overly complx weak link but mine has been faultless.
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Have you replaced the Li battery on the back of the A-B. My was acting up and the battery needed to be replaced, once I did everything work fine again.
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Greg where did you find the Li battery?
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on the back side of the A-B there was a small door, battery inside. It’s a memory back up battery. I could not find one online so I took my old one to Batteries Plus and they attach the old connectors to a new battery.
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my guess on the picture above it would be behind one of the two left hand boxes.
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How do you get behind those boxes? Just pull them out? or should there be a panel that I can access from the other side of the coach?
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Do not pull them out….While the system is energized will cause issue…under the flip out cover on the front is where the battery is
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The 2002 had an EPROM memory. The tech said most of those would never need a back up battery even though there was a dead one present.
When I asked the appropriate motorhome specialist what was wrong based on my symptoms ( no control of the house switches), could not utilize shore power or generator. My choices were drive it or let the house batteries slowly die or of course fix it. The only true choice was to fix it so the tech drove the 2 hrs. from Portland to Pacific Shores and fixed it only to have it fail a second time a few hrs later. He came back the second day and discovered when bank #5 was out it did not fail and it continued on the return to Oklahoma. Nothing operated by bank 5 works but it was not a major issue compared to alternatives.
The point, I think, is that there was probably nothing wrong with the Allen Bradley. There is probably something that bay 5 controls that has failed ( a relay). When the AB cpu sees the failure the whole system shuts down. Here is what is controlled by #5:
So On the advice of the tech,I will reactivate the wires one at a time in #5 until I get a failure on the CPU. At least that is the plan. The hard part is most motorhome people don’t really know much on the Allen -B yet it is an integral critical part of the system on some coaches. The AB tech knows the system but not much about how it is utilized on a motorhome. I think Jeff at East Tennessee would be the guy to call if this happened again. He and my new expensive friend from Portland together can hopefully fix this.
Wave
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Wave I live in Wilsonville Oregon, who did you call from Portland to work on this issue?
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Tauruspowercontrols.com
Tualatin. Tech was Lon
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I accidentally came across an ebay seller with a lot of NOS Allen Bradley stuff. I don’t know if any of it will work for a bus? Check it out.
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Yes, that tech mentioned that he could find parts on e bay.
I bet most of us never imagined such a pathology from a Prevost love affair?
wave
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