Originally Posted by mevman
I don't recall ever reading about a TSB or SS for the gauges problem. The LBCU diagnostics is good....the cables sometimes fixes the issue. Sometimes a faulty gauge is the issue. (I still have intermittent operation and haven't been able to nail down a faulty gauge, although I believe that's my problem).
I even purchased a used LBCU for a repair...and that wasn't it. Was able to help out a 2 members though with it.
While driving down the road one day one of my air pressure gauges suddenly dropped to zero setting off the alarm! Man, did that get the adrenalin flowing!!
While trying to determine what action to take I noticed the gauge "twitching", it then immediately jumped back up to normal pressure and the alarm silenced. I was thinking that the actual pressure could not realistically drop that fast and then recover. I figured that I had a dash instrument issue.
After googling the issue I found a post about the cable upgrade.
Calling Freightliner and explaining my issue the tech on the other end immediately knew what I was talking about. He gave me the part numbers I needed. Calling the local Freightliner shop I ordered the parts and picked them up about a week later.
I don't have the part numbers with me but Freightliner should set you up.
My dash was easy to remove, 6 screws and I was able to lift it way from the panel. COMPLETELY deplete any remaining air pressure by applying the brakes multiple times. Both primary and secondary air pressure gauges have air lines running to them. These two gauges are the only gauges that transmit data to the LBCU. Athens other gauges only receive data from the LBCU. Note the colors of the air lines before removing. You depress a brass collar on the air line fitting applying slight inward pressure. They should then pull right out. If you forget to relieve air pressure you will immediately know! LOL Although the lines are tougher to remove if under pressure.
My instrument panel was connected by the two air lines and two connectors on the backside of the LBCU.
Swapping the cables was easy. Just swap one cable at a time. The cable with the choke connects to the LBCU. Each gauge has a unique ID, they don't have a specific connection pattern to the cables.
You need to contact Freightliner Custom Chassis!!!! NOT your local Freightliner parts desk.
Hope this helps.
Also, that LBCU, If you purchase a USED functional LBCU you will get generator hours and odometer numbers from the previous coach the LBCU was installed in. New, the LBCU "burns in" the odometer reading when first installed. To get the actual mileage you have to drill down to the odometer diagnostics. In the ODO diagnostics you will see three numbers, IP ODO, ENG OPO and DIFF.
IP ODO is the instrument odometer reading, this is the prior coach odometer reading. ENG ODO is the mileage from the engine miles and DIFF is the difference between the two numbers. This information was passed on to me by the Freightliner tech. If you need actual odometer number you need to open the odometer diagnostics. If you want the actual number up fron you need to purchase a NEW LBCU, around 600 dollars last check.
If anybody has additional information please respond!