102c3 Dash Switch Wiring

[dj]

oops should only click once   sorry

[jraynor]

hey guys I got a silly assed question about that panel    does anyone know where I can get one for my 1988 102A3?   the pervious owner removed it before I got the bus and he couldn't find it or tell me why he removed it....its for the cruise dash lights ect     any information would be GREATLY appreciated    I do have a call into Luke @ US coach so maybe he has one haven't heard back yet...thanks again

Which panel? I'm redoing all of mine from my 1986 102A3. I think the differences may include the defroster is a 4 position rotary knob where mine is just a 2 speed and I think yours may have the bulb test switch where mine doesnt

[Jcparmley]

I don't even have C-I-6.  Is there a different schematic that I could purchase?  Perhaps one that shows which wires go to which pins on the back of the switch?

First issue you have there is that the I-2 drawings goes to the 96B3 and 102A3 Models. Be sure to match the drawing application to your bus before you get too deep in the drawing. You need Drawing C-I-6 and C-I-7. I don't even have page 6 in my set

[jraynor]

I don't even have C-I-6.  Is there a different schematic that I could purchase?  Perhaps one that shows which wires go to which pins on the back of the switch?

I would give MCI a call and ask for the missing diagram. Just call them and have your last 5 of your Vin and talk with their technical team. They will send it to you. Not sure about if they have a schmatica that says which wire goes to each pin. I have noticed in the master that shows some of the pin numbers. Basically do this, say ok I need to know about the cruise switch, look at the beginning of the electrical schematics in the table of contents and find the section on cruise control. Then go to that section, find the switch and see if it shows the pin numbers. If it doesn't, the circuits aren't to difficult to trace the path that the voltage follows. I.e, the power comes in on one leg, and when the switch closes, goes to the item (light,motor,etc.). Then power up the coach, then use a volt meter to determine which wire is hot then go from there.

The master schematic and others do show what pin# out of the plug of the harness each wire is as well. But some are more clear than others so check multiple schematics.

There is also the chance that someone modified something to make it work for them. That would make things worse. Like my bus, I have an extra cruise switch and I have no clue what it controls.

[Jcparmley]

I called MCI about the missing diagram and they said they don't have one.  Their book looks just like my PDF.  So I went ahead and installed all the gauges and switches and I have no power when I turn on the master switch.  So I must be missing something.  My guess is the 24 volt post on the back of the dash gauge panel is not getting power, therefore nothing is getting power.  Does anyone know which wire is the main power from the batteries?  Thanks

I would give MCI a call and ask for the missing diagram. Just call them and have your last 5 of your Vin and talk with their technical team. They will send it to you. Not sure about if they have a schmatica that says which wire goes to each pin. I have noticed in the master that shows some of the pin numbers. Basically do this, say ok I need to know about the cruise switch, look at the beginning of the electrical schematics in the table of contents and find the section on cruise control. Then go to that section, find the switch and see if it shows the pin numbers. If it doesn't, the circuits aren't to difficult to trace the path that the voltage follows. I.e, the power comes in on one leg, and when the switch closes, goes to the item (light,motor,etc.). Then power up the coach, then use a volt meter to determine which wire is hot then go from there.

The master schematic and others do show what pin# out of the plug of the harness each wire is as well. But some are more clear than others so check multiple schematics.

There is also the chance that someone modified something to make it work for them. That would make things worse. Like my bus, I have an extra cruise switch and I have no clue what it controls.

[jraynor]

I called MCI about the missing diagram and they said they don't have one.  Their book looks just like my PDF.  So I went ahead and installed all the gauges and switches and I have no power when I turn on the master switch.  So I must be missing something.  My guess is the 24 volt post on the back of the dash gauge panel is not getting power, therefore nothing is getting power.  Does anyone know which wire is the main power from the batteries?  Thanks

Looking at the wiring diagram for a 102C3, group 11 master schematic, I would do the following:
1. Turn on your 12v and 24v battery disconnect.
2. Walk over and open your front junction box. Measure 12 volts at the front junction box 12v bus bar, specifically stud 81 with the 20Amp. (Decals that show where everything is in Group A either drawing A-B2 or A-B3)

• If no voltage, the follow cable BL to your 12V main disconnect switch. If no power at the 12v Main disconnect, follow it to Vanner #1. If no power there, follow it to your middle battery tap. If no voltage there, then the issue is the battery.
• If you do get 12v, go to 3

3. Measure 24v from your front junction box 24v bus bar, specifically stud 37 with the 3Amp.

• If no voltage, follow cable BK to your 24v battery bus bar in your A/C junction box. the 105Amp stud should read 24v. If no voltage, follow cable BK-1/0 (its size) to 24v main disconnect. If no voltage from there, follow the 4/0 wire to the battery. If no voltage, Its the batteries not providing 24v.
• If you do get 24v, got to step 4

4. Standing from the outside of the drivers side window, with the electrical box open, Turn on the master switch by reaching through the window. Do you hear a contact block close?

Report back with the results and if you reach step 4 succesfully

[Jcparmley]

I must be an idiot but forgive me for asking which is the front junction box? I have 24 volts coming off of the battery. Is the front junction box the one under a drivers side window? If so I can't find stud 81.

Looking at the wiring diagram for a 102C3, group 11 master schematic, I would do the following:
1. Turn on your 12v and 24v battery disconnect.
2. Walk over and open your front junction box. Measure 12 volts at the front junction box 12v bus bar, specifically stud 81 with the 20Amp. (Decals that show where everything is in Group A either drawing A-B2 or A-B3)

• If no voltage, the follow cable BL to your 12V main disconnect switch. If no power at the 12v Main disconnect, follow it to Vanner #1. If no power there, follow it to your middle battery tap. If no voltage there, then the issue is the battery.
• If you do get 12v, go to 3

3. Measure 24v from your front junction box 24v bus bar, specifically stud 37 with the 3Amp.

• If no voltage, follow cable BK to your 24v battery bus bar in your A/C junction box. the 105Amp stud should read 24v. If no voltage, follow cable BK-1/0 (its size) to 24v main disconnect. If no voltage from there, follow the 4/0 wire to the battery. If no voltage, Its the batteries not providing 24v.
• If you do get 24v, got to step 4

4. Standing from the outside of the drivers side window, with the electrical box open, Turn on the master switch by reaching through the window. Do you hear a contact block close?

Report back with the results and if you reach step 4 succesfully

[jraynor]

I must be an idiot but forgive me for asking which is the front junction box? I have 24 volts coming off of the battery. Is the front junction box the one under a drivers side window? If so I can't find stud 81.

Yes, the front junction box is under the driver's window. Check out group A drawing B3. I assume this is yours being a C3 but you will have to check it against yours. If anything, take a picture of your junction box and send it in your next post

See the image below, I pointed out where 88 is near

[Jcparmley]

My junction box is group A drawing B2 and only has 65 studs.  I will take a pic tomorrow and send it to you in the next post.  Thanks for your help. 

Yes, the front junction box is under the driver's window. Check out group A drawing B3. I assume this is yours being a C3 but you will have to check it against yours. If anything, take a picture of your junction box and send it in your next post

See the image below, I pointed out where 88 is near

[jraynor]

ok so you have an older model 102C3 then. They seemed to have changed from a 65 stud to 100 stud at some point.

I was partially misleading you as well. The 81 is from the bus bar not a stud, But Im unable to locate your 12v bus bar. Use this method:

1. Turn on your 12v and 24v battery disconnect.
2. Walk over and open your front junction box. Measure 12 volts at the front junction box 12v bus bar, just measure the voltage found on each bus bar until you find 12 (Decals that show where everything is in Group A either drawing A-B2 or A-B3)
?If no voltage, the follow cable BL to your 12V main disconnect switch. If no power at the 12v Main disconnect, follow it to Vanner #1. If no power there, follow it to your middle battery tap. If no voltage there, then the issue is the battery.
?If you do get 12v, go to 3

3. Measure 24v from your front junction box 24v bus bar, just measure the voltage found on each bus bar until you find 24V. There may be multiple 24v bus bars
?If no voltage, follow cable BK to your 24v battery bus bar in your A/C junction box. the 105Amp stud should read 24v. If no voltage, follow cable BK-1/0 (its size) to 24v main disconnect. If no voltage from there, follow the 4/0 wire to the battery. If no voltage, Its the batteries not providing 24v.
?If you do get 24v, got to step 4

4. Standing from the outside of the drivers side window, with the electrical box open, Turn on the master switch by reaching through the window. Do you hear a contact block close?

Report back with the results and if you reach step 4 successfully

Ive attached a photo showing what the bus bars should look like, youll also see my main power cable as well. I would image that you should be able to get to step 4 above unless your batteries are your issue.

[Jcparmley]

Ok, I will check that out this afternoon when I can get out to the bus.  My batteries are less than a year old.  Also, when I turn on the main switch at the battery bay my lights, radio, turn signals, etc work just fine.  It's just my dash seems to have no power so I can't start the bus.  Strange.  I think there must be a power wire that is disconnected somewhere. 

ok so you have an older model 102C3 then. They seemed to have changed from a 65 stud to 100 stud at some point.

I was partially misleading you as well. The 81 is from the bus bar not a stud, But Im unable to locate your 12v bus bar. Use this method:

1. Turn on your 12v and 24v battery disconnect.
2. Walk over and open your front junction box. Measure 12 volts at the front junction box 12v bus bar, just measure the voltage found on each bus bar until you find 12 (Decals that show where everything is in Group A either drawing A-B2 or A-B3)
?If no voltage, the follow cable BL to your 12V main disconnect switch. If no power at the 12v Main disconnect, follow it to Vanner #1. If no power there, follow it to your middle battery tap. If no voltage there, then the issue is the battery.
?If you do get 12v, go to 3

3. Measure 24v from your front junction box 24v bus bar, just measure the voltage found on each bus bar until you find 24V. There may be multiple 24v bus bars
?If no voltage, follow cable BK to your 24v battery bus bar in your A/C junction box. the 105Amp stud should read 24v. If no voltage, follow cable BK-1/0 (its size) to 24v main disconnect. If no voltage from there, follow the 4/0 wire to the battery. If no voltage, Its the batteries not providing 24v.
?If you do get 24v, got to step 4

4. Standing from the outside of the drivers side window, with the electrical box open, Turn on the master switch by reaching through the window. Do you hear a contact block close?

Report back with the results and if you reach step 4 successfully

Ive attached a photo showing what the bus bars should look like, youll also see my main power cable as well. I would image that you should be able to get to step 4 above unless your batteries are your issue.

[jraynor]

Ok, I will check that out this afternoon when I can get out to the bus.  My batteries are less than a year old.  Also, when I turn on the main switch at the battery bay my lights, radio, turn signals, etc work just fine.  It's just my dash seems to have no power so I can't start the bus.  Strange.  I think there must be a power wire that is disconnected somewhere.

you saw main switch, as in singular. Do you not have 2 main switches? By the look of the diagram, it seems that you have a 12v and a 24v main switch. the 12v switch powers the main contact that provides the 24v to everything else.

When you turn the 24V on, do you hear a buzzer in the bottom right of your front junction box?

What year is your bus?

[Jcparmley]

I have a 1989 MCI 102c3.  I have one main switch at the batteries.  When I turn on the master switch at the dashboard I hear nothing.  When I flip the engine start nothing happens.  I do not hear a buzzer.

you saw main switch, as in singular. Do you not have 2 main switches? By the look of the diagram, it seems that you have a 12v and a 24v main switch. the 12v switch powers the main contact that provides the 24v to everything else.

When you turn the 24V on, do you hear a buzzer in the bottom right of your front junction box?

What year is your bus?

[jraynor]

I have a 1989 MCI 102c3.  I have one main switch at the batteries.  When I turn on the master switch at the dashboard I hear nothing.  When I flip the engine start nothing happens.  I do not hear a buzzer.

What is the last 5 of your vin? And do you have a Dual Vanner Setup? Im trying to match your coach to a drawing

[Jcparmley]

The last 5 of my vin is 42724.  I will look for the Dual Vanner when I get out to the bus.  Thank you so very much for your help.

Jared

What is the last 5 of your vin? And do you have a Dual Vanner Setup? Im trying to match your coach to a drawing