Hello
I thought I would start a new thread rather than resurrect an old one from a few years ago. I have no power at my master switch or dash. I have no power to the rear engine start panel. So this is what I know so far
I have 24 volts at the battery disconnect
I have both 24 volts and 12 volts at the vanner
I have 24 volts on the buss bar in the electric junction box under the drivers window
I have 12 volts on the 12 volt buss bar in the junction box under the drivers window
batteries are fully charged
When I switch the master switch on there is no low air buzzer
The engine start button does not work
The voltage gauge does not show any life.
I don't have accurate manuals because MCI says my bus was a prototype for the early 102c3 and they don't have a accurate manual. My bus has some parts from various different models. Very frustrating.
You probably don't have the modules and computer style cables going from front to rear junction boxes like mine does (2002 MCI). I had the exact same problem and it took several months to figure it out (due to my own lack of time to work on it mainly). What I found by isolating the front to rear cables, I had nicked a cable (8 pair plus shielding). Once I fixed that, it all came to life again. I sure hope you figure this out.
Not quite in neutral on shifter or does it have push bottons?? Maybe some switch on dash turned off? You have voltage at bus bars. Did you measure when in start position? Clean battery posts. Could show voltage, but drops to zero with any load.
I cleaned all battery posts. My dash has the micro switches.
Quote from: chessie4905 on September 23, 2022, 01:24:12 PM
Not quite in neutral on shifter or does it have push bottons?? Maybe some switch on dash turned off? You have voltage at bus bars. Did you measure when in start position? Clean battery posts. Could show voltage, but drops to zero with any load.
I'd double check the cables and conectors at the batt and the batt cutoff switch first.
I cleaned and tightened all the connections at the battery. All are tight and clean.
Quote from: Van on September 23, 2022, 04:54:08 PM
I'd double check the cables and conectors at the batt and the batt cutoff switch first.
Did you clean the ground connections on the frame? Just as important as at the battery.
What bus are we working on? The one in your tag line, a 96DL or an early C model, as described in the opening post?
Who gave you that line about no manuals?
'96 is not an early model.
Happy coaching!
Buswarrior
Hook up a push button start button to the starter to see if it starts without all the stuff between the start switch and the starter,
The bus I am working on is the 89 102c3 with a 6v92TA mechanical. The parts people at MCI are the ones that told me about the manuals and that my bus was a prototype bus. They couldn't even look it up by the vin because it wasn't in their system. I did check the chassis grounds as well. All are tight and clean.
Quote from: buswarrior on September 24, 2022, 01:34:48 AM
What bus are we working on? The one in your tag line, a 96DL or an early C model, as described in the opening post?
Who gave you that line about no manuals?
'96 is not an early model.
Happy coaching!
Buswarrior
Yes, I did that and that is the only way I can start the bus now. It's a mystery.
Quote from: Dave5Cs on September 24, 2022, 12:33:33 PM
Hook up a push button start button to the starter to see if it starts without all the stuff between the start switch and the starter,
For the love of GAWD, put it in your tag line, your head is spinning, and so are ours...
Mechanical, electronic, i think i fell and struck my head...
Happy coaching!
Buswarrior
Quote from: Jcparmley on September 24, 2022, 01:23:54 PM
The bus I am working on is the 89 102c3 with a 6v92TA mechanical. The parts people at MCI are the ones that told me about the manuals and that my bus was a prototype bus. They couldn't even look it up by the vin because it wasn't in their system. I did check the chassis grounds as well. All are tight and clean.
???
I don't understand what you mean.
I am selling the 102dl3 this week and I am trying to get the 102c3 to run so I can sell it as well. I am unable to continue my build due to a spine disease. I am looking at purchasing a 97 Monaco motorhome so I can at least take my kids on some trips ASAP.
Quote from: buswarrior on September 24, 2022, 01:48:31 PM
For the love of GAWD, put it in your tag line, your head is spinning, and so are ours...
Mechanical, electronic, i think i fell and struck my head...
Happy coaching!
Buswarrior
At the bottom of your posts, your tag line misinforms those who aren't memorizing every thread.
Go into your profile and make an adjustment that lets those of us older demented readers not assume its all about the DL3
Quote from: Jcparmley on September 24, 2022, 03:46:55 PM
???
I don't understand what you mean.
I am selling the 102dl3 this week and I am trying to get the 102c3 to run so I can sell it as well. I am unable to continue my build due to a spine disease. I am looking at purchasing a 97 Monaco motorhome so I can at least take my kids on some trips ASAP.
Check the step light and chimes switch. If it was ever a hound it needs to be on to start the bus! (sort of a anti-theft trick they did!)
;D BK ;D
On the passengers side on the transmission you will have the neutral switch which has two wires going to it. Take a paperclip or jump wire and jump those teo wires and see if it will start then. That would mean your neutral switch needs replaced or the rely in the top of driver side rear fuse box is not good. There should be a ice cube rely in the front fuse panel at heater fuse. That is the same as start rely fuse and can move it to the rear to see if that lets it start.
I am able to start the bus with a button connected directly to the starter. I just don't have power up at the dash on the main switch. Could the neutral switch interrupt power to the main switch?
Quote from: Dave5Cs on September 26, 2022, 09:11:55 AM
On the passengers side on the transmission you will have the neutral switch which has two wires going to it. Take a paperclip or jump wire and jump those teo wires and see if it will start then. That would mean your neutral switch needs replaced or the rely in the top of driver side rear fuse box is not good. There should be a ice cube rely in the front fuse panel at heater fuse. That is the same as start rely fuse and can move it to the rear to see if that lets it start.
Quote from: Jcparmley on September 26, 2022, 04:55:28 PM
I am able to start the bus with a button connected directly to the starter. I just don't have power up at the dash on the main switch. Could the neutral switch interrupt power to the main switch?
No the neutral switch will not interrupt power to the main switch.
But it will from the go switch to the starter.
Quote from: Dave5Cs on September 27, 2022, 07:53:09 AM
But it will from the go switch to the starter.
Yes but if I understand correctly the OP problem is he has no power at all to the dash.
Yes, that is correct. I don't have any power to the dash.
Quote from: thomasinnv on September 27, 2022, 10:20:48 AM
Yes but if I understand correctly the OP problem is he has no power at all to the dash.
Quote from: Jcparmley on September 27, 2022, 02:56:34 PM
Yes, that is correct. I don't have any power to the dash.
Power at both sides of batt disconect? Main breaker tripped? Power @t the dash switch? Should be easy to troubleshoot with a simple Volt meter.
even simpler, start with a 12 or 24 volt test light. may have a circuit breaker that went bad. btw, Harbor Freight sells a package of 3. a 12volt test light, a 24 volt test light, and a continuity tester for like 7 bucks. can't afford to pass that up. Centech brand.
Yes, I have power at both sides of the battery disconnect. I can't seem to find the main breaker. The first bay on drivers side has a breaker panel but there is no breaker in the spot that says "main breaker" (see photo) I have no power at the dash or dash switch. I do not have power at the rear control panel next to the engine. I do have power at the main relay under the drivers window.
Quote from: Van on September 27, 2022, 05:05:14 PM
Power at both sides of batt disconect? Main breaker tripped? Power @t the dash switch? Should be easy to troubleshoot with a simple Volt meter.
Power at main relay. Take cover off and actuate the relay. What happens then? Some you ground the coil and some you give voltage to. TRY momentarily Either way. Nothing to lose.
My old relay would only work when I manually actuated it. So I removed it and put a new one in. I will take the cover off and see if I can manually actuate that one as well.
Quote from: Bill Gerrie on September 28, 2022, 04:50:01 AM
Power at main relay. Take cover off and actuate the relay. What happens then? Some you ground the coil and some you give voltage to. TRY momentarily Either way. Nothing to lose.
Check the connection (big cable) on the back of the alternator and tell us what the voltage is or if you even have power there,the wiring goes through the engine rail to a bus bar from the rear panel to power the dash on a C it makes a loop on Tom's model C.there is also a ground wire on the passenger's side by the starter if that gets broken nothing works lol only took a 1/2 of day to figure that out
ok, I am back to trying to figure out this electrical problem. I still have no power to the master power switch on the dash and therefore can not start the bus from the dash. I can start the bus by installing a button on the starter itself. I can also turn the engine off by pushing the lever on top of the throttle body. I removed the air line to the engine shut off cylinder and capped it temporarily because it would shut down the engine once the air was built up. I will check the big cable on the back of the alternator for power and get back to you all. Thanks for the help.
Quote from: luvrbus on September 28, 2022, 07:52:59 PM
Check the connection (big cable) on the back of the alternator and tell us what the voltage is or if you even have power there,the wiring goes through the engine rail to a bus bar from the rear panel to power the dash on a C it makes a loop on Tom's model C.there is also a ground wire on the passenger's side by the starter if that gets broken nothing works lol only took a 1/2 of day to figure that out
I hooked up the button and the bus starts right up.
Quote from: Dave5Cs on September 24, 2022, 12:33:33 PM
Hook up a push button start button to the starter to see if it starts without all the stuff between the start switch and the starter,
Calling all experts in electrical stuff. Please help me figure this out. I need to get this bus moving again. Thanks
It is not hard it is just a time-consuming process you start at the dash checking for power on both sides on the master switch on the dash then go to the front panel remove the cover from the rear panel and check the same wire number in the rear panel, it gets confusing when we don't get enough information, when you find the problem, it will be a simple solution. Buy you a good 12/24 light move the clip to another ground if it lights, and if it doesn't lite you know the ground is bad, If the boxes look like a rat's nest with spliced wires, then you have major problems trying to redo wires that worked before the guy did some major wire changing,MCI never changed the schematic very much between the models 8,9 and C any schematic for either would work for you ,I went through this on Mike and Kays MCI 9 for over a week you are just getting started
The previous owner spliced a bunch of stuff in this bus. My first post in this thread shows the process I went through months ago. I will start from the begining and try to track down where the power is being severed. I will post my results asap. Your advice is invaluable. I really appreciate it.
Quote from: luvrbus on December 12, 2022, 04:35:05 PM
It is not hard it is just a time-consuming process you start at the dash checking for power on both sides on the master switch on the dash then go to the front panel remove the cover from the rear panel and check the same wire number in the rear panel, it gets confusing when we don't get enough information, when you find the problem, it will be a simple solution. Buy you a good 12/24 light move the clip to another ground if it lights, and if it doesn't lite you know the ground is bad, If the boxes look like a rat's nest with spliced wires, then you have major problems trying to redo wires that worked before the guy did some major wire changing,MCI never changed the schematic very much between the models 8,9 and C any schematic for either would work for you ,I went through this on Mike and Kays MCI 9 for over a week you are just getting started
Does anyone have a clean schematic that shows the order of master switch and start switch. My manual is a digital one and very hard to read. It's not very clear even with my cheater glasses. :)
Or if someone can tell me the order of the circuit that would be great.