Craig
Forum Replies Created
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Looks like I have bulb burnout. Good info Mike.
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Me too
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As the old timer said, ”If it had teeth it would’ve bit me”. Turns out the whole problem was caused by a bad fuse. Note I say bad, not blown fuse. The rest of the story:
I contacted Liberty today to buy the circuit sheets for my coach. I had been miserly and avoiding buying these for years. They would have saved many hours of struggling with electrical issues in the past and maybe this time. The sheets verified the red wire in my prior post, which in hindsight is PLAINLY labeled “7” (here is where the “would have bit me” allusion applies) runs to fuse 7 in the coach electric bay. I check the fuse, same voltage both sides of the fuse through the little holes in the top. Then I look again, what is that brown color on the exposed part of the left spade of the fuse? I pull it out and the plastic is swollen on both faces overlying that spade terminal. Hmmmmm again. I get a new fuse stick it in the socket and everything works perfectly.
What happened? Maybe some contaminant got on the fuse terminal or the socket and prevented good contact, or the socket was loose, arcing occurred, some oxides formed and poor connection. Hence when I connected the B connector back at the Webasto control module one of whose wires which again in hindsight I see has the same “7” circuit in one of the terminals, the draw from the Webasto control module was enough to reveal the poor connection back at the fuse – seen yesterday by me as a voltage drop at the relay red (7) wire when I plugged in the B connector.
Photos of the offending fuse are below, as well as autopsy photos showing the innards of the rascal. The inside of the fuse plastic appears melted by the heat caused by the poor connection.
LESSONS LEARNED
OCCAM’S RAZOR
The simplest solution is usually the right one. Look, really look, at the simple stuff before you go tearing things apart trying to fix them. Fuses, relays, connectors, starting with those you can get to without taking things apart. I mean I was ready to rip apart the control module and solder in new electrolytic capacitors (even ordered a capacitor assortment on Amazon) and did research on replacement circulation pumps. A photo of the label from my pump is attached in case it helps someone who needs one in the future, though the thing looks like it will last 100 years.
EXPLORE YOUR COACHES INNARDS WHEN IT IS CONVENIENT
If you plan to do some or all of your own service work, do as Jon has implored previously and take every panel, cover, access plate, whatever off and see what’s behind it. This does several important things:
- You learn what is back there.
- You find out if there are any frozen/stripped or oddball fasteners that you don’t have a left handed Lithuanian 7 point driver bit for. Nothing against Lithuanians. The time to find this out is while you are in space dock, not out in deep space as Scotty would say.
- When putting fasteners back in place on panels that are exposed to the elements, put a liberal coat of never seize on them so 5 years from now when you have to take it off “out there” in the wilderness, it will come off without breaking. Also consider tossing those infernal Phillips drive fasteners and putting in a hex head equivalent.
- You might just see something about to break/rub through/fall off, etc. that you can fix.
INVEST IN DOCUMENTATION
If like me you did not get the manuals with the coach, don’t cheap out and fail to buy them. The $150 was well spent. Indeed after some conversation about what I was working on, Todd at Liberty even sent me (unsolicited) an extra page that had the actual WIRING DIAGRAM of the involved circuits for the Webasto. Lonestar pointed out at least once before he has never seen a wiring diagram from a Liberty. They do exist at least at the mother ship.
Thanks to all who offered help and suggestions on solving this mystery.
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The spring loaded belt tensioner has a 1/2″ square socket in it and a 1/2″ 18 to 24″ breaker bar is all that is needed to easily relieve belt tension.
If the belt is the correct size with one hand the tension can be removed using the bar and with the other hand the belt can easily be installed or removed. If that is not the case, as explained above the belt may not be the correct one. Do not use screwdrivers or pry to get a belt on or off. It can damage the belt or pulley.
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Happy 4th hope you all have a blessed day!
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All well and good, but it does not answer the issue of pressures and temps opening the valve upon every cold start up.
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Agree with Art – Wow! What a glimpse! Craig… Please post additional pics of your engine compartment, and tell us how you did it.
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Thanks everyone for the responses. I had the owners manual, but it was not clear about compressor operation, just the switch usage.
What Jon was able to get from his contact was a detailed electrical wiring diagram which clearly showed that the compressor should not engage when in heat/vent and what relay controls that operation – From the diagram the A/C clutch should only run with the switch in the A/C position, power comes from the R-33 relay after the alternator starts charging and is power waiting at the switch. Switched to the A/C position the contacts between pin 5 and 1 on the switch, this sends power to post 52 in the FJB then to post 36 in the RJB then down to the High then low pressure switch and if all that is good the clutch is engaged.
So now that it is clear it is not running as expected I can use the diagram info to check relays and see if I can figure out why it is running.
Thanks for the great support as always in this community!!
PS – Having the Prevost electrical diagrams would be awesome as I often find that is the info I need and don’t have. If anyone knows how to get access to those for a coach that would be great.
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was okay with most of it until the end where for some reason he’s under the impression that the 50k fix will need to be repeated every ten to fifteen years, so budget 3k or so a year for this.
Well there goes that credibility. I had it done and for the record that is a permanent fix. The care and attention by Prevost to remedy this problem is 110%.
Can you post the Andrew Steele address ?
Never mind, just went to YouTube enter if you have interest… Andrew Steele
AL
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Need to move on top of your mountain Harry as Llano Co. Texas just canceled it all.
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This looks awesome, in 20 years I can buy it for 150K. Can’t afford it now…
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Hi Jon,
I am not pointing the fingers at anyone on my comment about our political leaders finally taking this seriously. If you look at history this seems to always be the case.
Thanks
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You mentioned that you replaced the top row of the house batteries recently. Usually, all batteries are replaced as a set. Maybe your bottom row of batteries is now not taking a charge.
You can disconnect them with the coach shut down and see if they take a charge with an external charger. Better yet, just replace the bottom row as well.
Kudos for a very clean battery compartment. Reminds me to clean mine.
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Jeff probaly another long shot Since our coach is a 1994 XL. The bushings I used are Prevost part # 630062
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Napa Gold Part # 3120 MP