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(Moderator:
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97 Prevost H341 Coach No Crank No electrical power
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Topic: 97 Prevost H341 Coach No Crank No electrical power (Read 6609 times)
mick10
Newbie
Posts: 5
97 Prevost H341 Coach No Crank No electrical power
«
on:
May 23, 2018, 02:24:46 PM »
After a lot of research I finally bought a coach (97 Prevost) to convert from a reputable coach line, drove it 500 miles home with no issues except the windshield washer pump not working. I parked it, removed the seats bought all the maintenance items to tune it up but to my dismay one day I went to change the oil and there was absolutely no electrical power-no crank, no lights not even any dashboard lights. So I left the dashboard master switch on and went out to eat. When I returned all the interior bus lights were on and I started the bus right up no problem.
So every day I would turn the master switch on to be sure I still had power--sometimes start it up and take it for a drive and when I parked it I always turned the dash master switch off.
Now when I turn the dash master switch on there is nothing-the bus is completely dead.
All 4 Batteries show 12.6 each and there is over 24v coming from boost terminals.
Called Prevost PASS they directed me to the main relay and a couple of relays in battery compartment which I purchased and replaced. Still nothing-completely dead.
Called Prevost again and found it hard to understand the tech as he had a heavy french accent but bought a few more relays-still dead.
The main relay was $400 and I have spent close to $1000 in relays and fuses and yet I feel I am missing an issue that someone with a similar coach may have knowledge.
I have owned the coach for about 3 months and am now a Little anxious that I may have to get it towed in order to get repaired.
I have good mechanical knowledge when it comes to cars but this has me stumped. Any ideas or help would be much appreciated.
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windtrader
Hero Member
Posts: 2446
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #1 on:
May 23, 2018, 02:46:43 PM »
It's better to diagnose the problem before buying parts. Diagnose means using an electrical meter to follow the wiring diagram, probe each electrical junction, and determine specifically where the fault is. It may not even be a part, maybe an intermittent shorting wire. Hope you find the root cause soon and stop spending unneeded monies. Good luck
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Don F
1976 MCI/TMC MC-8 #1286
Fully converted
Bought 2017
thomasinnv
Derrick Thomas
Hero Member
Posts: 1492
I may be nuts, but only for buses
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #2 on:
May 23, 2018, 02:48:42 PM »
I would suggest getting hold of a wiring schematic and start checking things out. You're going to remain in the dark if you don't have some kind of schematic to give you something to follow.
Sent from my SM-G930T using Tapatalk
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Some are called, some are sent, some just got up and went.
1998 MCI 102-DL3
Series 60 12.7/Alison B500
95% converted (they're never really done, are they?)
richard5933
Hero Member
Posts: 3963
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #3 on:
May 23, 2018, 03:03:01 PM »
I don't know much about the working of a Prevost, but I'd say that a universal cause of many issues like this is a faulty ground connect somewhere. Especially if the problem started slow and built to a total failure like this. If those relays are like most, they require a ground connection to function as well.
My first method of attack would be to find every ground connection you can find, and then one by one service them. They should each be disconnected, cleaned (chemically and/or physically as needed), reconnected, and then tightened to the proper torque.
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Richard
1974 GMC P8M4108a-125 Custom Coach "Land Cruiser" (Sold)
1964 GM PD4106-2412 (Former Bus)
1994 Airstream Excella 25-ft w/ 1999 Suburban 2500
Located in beautiful Wisconsin
buswarrior
Hero Member
Posts: 6569
the old one: '75 MC8 with an 8V71 HT740
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #4 on:
May 23, 2018, 03:43:13 PM »
Creeping Green Death in the big battery cables?
Cut the heat shrink off those terminals. If they are good, you can goop 'em up to protect them again, same as a car.
But if you find the corrosion...
Happy coaching!
Buswarrior
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Frozen North, Greater Toronto Area
new project: 1995 MCI 102D3, Cat 3176b, Eaton Autoshift
mick10
Newbie
Posts: 5
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #5 on:
May 23, 2018, 04:02:00 PM »
I am seeing a lot of green even on the relay terminals so I will check the big battery cables as well as all grounds and try to get hold of a good wiring diagram as the one on the Prevost site is too small to read.
I was hoping there was a common weak spot common to this type of bus so at least I could fire her up.
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luvrbus
Hero Member
Posts: 26067
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #6 on:
May 23, 2018, 04:21:18 PM »
Breakers on the bus bars on the H-41 cause you a lot of grief
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Life is short drink the good wine first
brmax
Hero Member
Posts: 629
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #7 on:
May 23, 2018, 05:39:43 PM »
I would get the winshield shaded some how then take some steps to electrically check that dash master switch. Following up with these particular wire routings.
Best of luck and have a good day
Floyd
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1992 MC9
6V92
Allison
bandsaw
Newbie
Posts: 38
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #8 on:
May 25, 2018, 08:13:13 PM »
Hello, I read your post about your Prevost. I am in the process of converting a 1998 H3-41. I am curious about where you are located. I am in Oregon and I wondered if you were close.
As far as your electrical issue, the biggest battery disconnect solenoid is in the rear side electrical panel. It is on the back wall above the start batteries. You could unbolt the cables and move to the other post to by pass it. There is a small switch in the same panel that will disable the solenoid. The switch allows a mechanic to disable the power while he is working on the bus.
Bandsaw
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Jon
Hero Member
Posts: 644
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #9 on:
May 27, 2018, 05:07:27 AM »
Prevost has excellent and complete information on their web site so don't spend a penny trying to buy electrical diagrams or service manuals. The advice to follow the circuits to diagnose the issue is correct.
If you are looking for a weak point that impacts starting it is the rear start selector switch on the RH side of the rear electrical box, but that may have nothing to do with your problem.
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Jon
Current coach 2006 Prevost, Liberty conversion
Knoxville, TN
Geoff
Hero Member
Posts: 1931
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #10 on:
May 27, 2018, 06:37:43 AM »
It has been hinted at in the previous posts, but it sounds like poor battery connections...
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Geoff
'82 RTS AZ
luvrbus
Hero Member
Posts: 26067
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #11 on:
May 27, 2018, 06:43:28 AM »
The H-41 is a unique bus I owned 1 for a while down load the schematics from Prevost ,why they used so many relays in the system is ? to me and the Potter relays are not cheap.A operators manual is a good source of info on a H-41 do you have one ?
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Life is short drink the good wine first
mick10
Newbie
Posts: 5
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #12 on:
May 29, 2018, 09:58:34 AM »
I appreciate all the good suggestions and I am looking for an operators manual. In a way I am lucky this problem happened while I was at home and not somewhere where I would be stranded.
In addition, it has shown be the complexity of a coach's electrical system and the importance of keeping it in good condition. So far I have discovered many broken fuses, disconnected wires and lots of green corrosion.
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mick10
Newbie
Posts: 5
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #13 on:
July 13, 2018, 01:17:58 PM »
I've made some progress on my electrical issue:
Jumped main relay in battery compartment and the bus started when I turned the key. However this only worked once.
Then while still jumped no start from key but it would start from rear engine compartment--however this worked 3 times then no start rear or front.
Now with main relay still jumped-- I can start bus by jumping starter motor. This seems to always work.
With one major issue the red do not shift light stays on and the allison pad is not illuminated. and I can not shift bus.
Any thoughts as this seems very strange.
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luvrbus
Hero Member
Posts: 26067
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #14 on:
July 13, 2018, 02:02:50 PM »
Turn both master cut off switches off and check for power at the transmission,the transmission and engine ECM should still have power with both disconnects off ,the relays are in the rear junction box on a H- 41,you have a grounding problem some where IMO
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Life is short drink the good wine first
buswarrior
Hero Member
Posts: 6569
the old one: '75 MC8 with an 8V71 HT740
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #15 on:
July 13, 2018, 03:00:38 PM »
Try shutting all down, disconnect and reconnect your jumper, and maybe VROOM?
Depending on vintage, one start attempt per "key-on" is all you get, so dumb driver doesn't engage starter when it is already running.
Your jumper wire acts like a permanent "key-on".
Shooting in the dark, yours might not be like the newer ones?
Happy coaching!
Buswarrior
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Frozen North, Greater Toronto Area
new project: 1995 MCI 102D3, Cat 3176b, Eaton Autoshift
luvrbus
Hero Member
Posts: 26067
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #16 on:
July 13, 2018, 05:47:10 PM »
I have a feeling if you clean all the plugs,grounds and connections at the ECU on the Allison your problems will go away
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Life is short drink the good wine first
robertglines1
steam nut
Hero Member
Posts: 4557
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #17 on:
July 13, 2018, 06:07:19 PM »
still haven't shared much information about yourself. I don't answer if your profile is blank. Go with grounds first then check starter solenoid as there is a disk in there that gets corrosion or hot spots on it. prevostcar.com last letter in your serial # plus last 4 numbers---tech manuals.That is general knowledge.
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Bob@Judy 98 XLE prevost with 3 slides --Home done---last one! SW INdiana
mick10
Newbie
Posts: 5
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #18 on:
July 16, 2018, 10:34:02 AM »
Problem Solved thanks to luvrbus and others on this board suggestions.
With the help of a great Volvo tech from 401 Truck Source he found the corroded transmission fuses and spliced in new fuses. In addition he found a bad connection at the dash power switch and rewired it.
Looks like water was entering the rear electrical box causing the issues.
So there were 2 different electrical problems which made the diagnoses difficult.
Again, this site has been very helpful and much appreciated.
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robertglines1
steam nut
Hero Member
Posts: 4557
Re: 97 Prevost H341 Coach No Crank No electrical power
«
Reply #19 on:
July 16, 2018, 07:02:32 PM »
welcome glad you updated your profile.
Logged
Bob@Judy 98 XLE prevost with 3 slides --Home done---last one! SW INdiana
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97 Prevost H341 Coach No Crank No electrical power
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