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Erratic Gauge Readings
I have a 99 Country Coach, 98 Prevost XL, and begun to get erratic gauge readings
today. The 24 volts would go down to 20V
for a while and bounce around before returning to normal and doing the same
again. The front and rear air pressure
gauges would read normal and occasionally bounce to zero for a few seconds
before returning to normal.I checked the 24V at the battery jumper connections and the
voltage was as expected at just above 27V.
So, I’m confident the problem is most likely a poor connection in the
communications bus to the gauges. BTW, I
have a Country Coach with a glass display.
I doubt it’s the computer that drives the display given all other gauges
perform normally.Any thoughts on which connectors to start with? Any thoughts on my logic being flawed? I’m in Minot, ND so getting commercial help
is not going to happen here. They have a
Detroit Diesel shop, but it doesn’t do
service; they only sell parts.Thanks,
Gil
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10 Replies
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Gil,
Welcome to no-man’s land. Your dash is pure Country Coach. Even though as a CC item it would be viewed as part of the “house” your dash is neither. It obviously at some point in the coach receives data from the Prevost chassis likely in the form of an electric signal of some sort, but then the CC portion takes over and displays it on the CC dash.
Back when I worked for a living I had a lot of computerized manufacturing equipment. The machine was typically made by the folks whose name was on the machine, and the controls were made by folks whose name was on the computer controls. In between was what both called the “interface”. Any time the machine acted up in a fashion that suggested it could be a control problem or a machine problem both manufacturers would blame the other. We were in the middle until we could rule out one or the other. We thought we died and went to heaven when we finally hooked up with technicians that serviced both. That is the kind of guy you need right now. My suspicion is it is related to the CC stuff or the interface between Prevost and CC because so much has gone whacko all at once.
Start with Miles Circo or Nick Hessler. Pray.
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Gil,
Owned and repaired a CC Affinity for 10 years I recall seeing posted something close to what you have.
The problem was a ign switch. I don’t remember if it was loose wires on the back or the control inside. CC used ign switches that were available thru NAPA and are very inexpensive.
1) Wiggle the crap out of the switch and see what happens.
2) Wiggle the wires on the back and see if anything changes.
AL
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Gil,
Everything runs through the ECM, that big scary thing in the front bay. If it’s related to the ECM, Detroit, Prevost or most anyone else you find will not be able to help. You need to contact Nick Hessler, omnitech_nick1@yahoo.com. Nick worked for CC and actually did the electrical on my 2000 when it was new. Miles has the parts, but Nick is the go to guy.
Nick is an Advertiser with us, but his Ad is down because of a snag on our end.
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Thanks all,
The best I can tell the Prevost datalink (Detroit, Allison, etc…) does not go through the ECC, although it may. For the life of me I can’t understand why anyone try to modify a standards based datalink. I had assumed that CC simply intefaced the glass dash computer to the Prevost provided datalink, just like Silver Leaf does.
I’ll reach out to the expert and see what he says. I was going to hook up the Silver Leaf interface I had from my last coach, but the data connector is not the same. I’ll be calling Silver Leaf to get the right one.
Again, thanks all,
Gil
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Call Nick, he can help. He does this for a living so there might be chage for his service or he might help you out as a favor. I had the CC glass dash and finally replaced it with a SilverLeaf. Everything from Prevost goes to a computer that is most likely behind the drivers seat in a cabinet with the Bose module. (if u have a Bose) Everything for the dash is driven from that pc.
It’s pretty complicated so give him a call. He will be back in Natcogdoches Texas at Xtreme Paint & Graphics after the 4th.
1-541-954-2452
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Oh and Gil, you’ll love this, the computer Charles mentioned is MS Dos and takes a 3.5 floppy, remember those! If your’s is like the one I had, the top of the cabinet behind the seat where the Bose sleeps comes off, it’s velcroed and really hard to lift off.
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Thanks Tom. Yes I have a diskless computer and it lives where the Bose amplifier is behind the driver’s seat. Access to my computer must be a bit different than yours. I can remove the end facing the center of the bus and remove the computer. Although the computer is the heart of the system, tracing the arteries that feed it is a bit of a challenge. CC had to translate the analog systems to something the computer would understand. In this case it appears they may have translated them to serial data. I have discovered where the device is that translates air pressure. What I haven’t found is where it’s getting it’s voltage reading.
I’ve traded a couple of emails with Nick. He’s a bit busy right now but will look for the wiring diagram when he gets a chance.I have Silver Leaf’s VMSpc from my last coach. I was going to hook it up to see which readings are supplied directly over tghe bus used by Detroit, Allison, and possibly Prevost. Unfortuantely, I have the wrong connector. Silver Leaf is sending the right one to Alaska for me to use when I get there.
Did you install a Silver Leaf Glass Dash? If so, can you tell me what was involved and who did it? I’ll still need a translator for anything not on the communications bus or move those things to dedicated guages, which is not my preference.
Thanks again,
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I didn’t change it out to Silverleaf and the owner of my previous bus has the complete set of floopy discs if you run into trouble with it being softward related. Have you tried to re-boot the computer? You may want ot talk to Silverleaf and find out where their point of service is located in case you have to go that way. CC’s system was call Sun Mullen (spelling) and was propritary to their coaches. The computer under the cabinet also controls the speech system (the bitch in the box) and those boards are located above the driver behind the tv.
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FYI Gil, a friend just replaced his CC dash with the Silverleaf Glass Dash at a cost of 10K.and Silverleaf installed it. One good thing is it would be supported.
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Thanks Elliot. I wasn’t sure if Silver Leaf did their own installations or relied on certified installers.
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