Fuse Box Help

[Neorush]

I'm trying to understand the diagram on my bus' fuse box / under the driver window panel. Some of the items are really obvious like the solenoids or the heated mirror timer. But nothing has labels on them. I'm trying to understand what I'm looking at. Are the two vertical bus bars just relays? There is a separate fuse panel under the steering wheel. Any help here would be HUGE, I don't mind reading on my own if you even have a good resource for this. My googling and searching here didn't turn up much.

 

[Mountain Gnome]

Is that a BlueBird?
As mine also seems, your diagram does not match exactly what is in the box! Closer than mine, though.
The vertical rows in the middle are self-resetting circuit breakers, I believe.
MAYBE the relays in the diagram correspond to the relays in the other, hidden panel behind the windshield wipers?

 

[Neorush]

Is that a BlueBird?
As mine also seems, your diagram does not match exactly what is in the box! Closer than mine, though.
The vertical rows in the middle are self-resetting circuit breakers, I believe.
MAYBE the relays in the diagram correspond to the relays in the other, hidden panel behind the windshield wipers?

Yes, 2002 Bluebird All-American. They could be the circuit breakers, but they obviously don't match the diagram at all.

 

[banman]

Yes, 2002 Bluebird All-American. They could be the circuit breakers, but they obviously don't match the diagram at all.

By the look of 'em, they are circuit breakers...

Can you bounce the #'s on the diagram with the any #'s printed on the panel itself?

Not all diagrams are 'hard road maps to scale'

The diagram on your panel may be electrical correct without being the actual physical pathway.

For instance -- often a circuit to ground will be shown on a diagram wherever there's room on the diagram, but not reflecting where the wire is physically being run from/to...

 

[Mountain Gnome]

Yes, 2002 Bluebird All-American. They could be the circuit breakers, but they obviously don't match the diagram at all.

The diagram shows two stacks of breakers 14 high.
If you look at the actual fusebox, there are two rows that are spaced to hold a total of 14 high. Some are missing.

 

[Mountain Gnome]

From what I saw in my diagram, the breakers are marked as something that does not nessesarily correspond to reality. But I've only begun to dig into the wiring. Wish Bluebird had a real diagram for all the circuits in my bus. But no.

 

[Mountain Gnome]

Ironically, I'm having a similar fuse box problem.


No start. Motor spins.


No dash lights.


Cummins diagram says dash lights are powered by the IGN switch, then grounded into the computer, which should turn them all on for testing at startup (doesn't happen), and individually to indicate problems.


Dash light fuse has low voltage at all times. Voltage changes when the key is switched on, but still low. Wire feeding into and out of it is solid black, as most wires in the dashboard fusebox. All dashboard fusebox wires are either black or red/black. All disappear into the main harness.



IGN-chassis and IGN-directional fuses switch on/off properly.


Tested all positions of the key switch (off, IGN, Start, Accessory) while disconnected, all seems proper.


Using a multimeter on the OHMS setting, continuity is found between the key-switch harness connector and the two IGN fuses with near 0 OHMS. Two Red/black wires feed off the switch, and same color at the two fuses. Seems correct.



Two other red wires feed off the IGN switch; all disappear into the main harness. I must assume (one of) these are for the computer? There is no fuse or circuit breaker that says ECU or PCM or similar.


Now I am ?guessing? that the IGN switch sends power to a relay, and that relay powers the dash lights fuse and the computer. That relay would be bad. But then how is the computer fused?


Can't get to the computer's harness connector without taking a lot of stuff off the motor. No fuse I can see there. The computer's harness disappears up into the dash from under the vehicle, just below the hidden relay panel that is behind the windshield wiper under the driver's widow on the outside of the bus.


In that hidden panel can be found multiple red/black wires that look like the same gauge as coming from the IGN switch harness connector. Two are connected to two relays that are separate from the others. But other red/black wires disappear behind the "gang" of 12 relays in the middle of the panel.


Ode to BlueBirds' wiring diagrams:


Oh diagrams, oh diagrams, why art thou lame and incomplete?
Oh diagrams, oh diagrams, I just want to drive down the street.
Distribution you need to show,
Of power circuits I need to know.
Oh diagrams, oh diagrams, how's the computer wired?


without answers, I'm either replacing the relays one at a time, or worse, tearing apart the main harness and making a real mess while trying to manually trace wires from one connector to another.


THIS is why I'm going to hate my bus in the long run. It's like working on an old AMC Jeep's wiring.


Went to wire in a new stereo radio a while back. Old speakers (4 total) in the ceiling have random colored/sized wires, seems some are wired in parallel, some in series, all in mono. Everything is hidden in the walls... Just makes no sense to me.

 

[Mountain Gnome]

Found a "body" wiring diagram for BlueBird All Americans from 1999-2003 on CentralStatesBus.com. Likely the same basic concept/setup as my 1999 TC1000-HandyBus. But nothing about the starting or computer systems. Many pages say "see circuit completed in the Chassis - Standard Equipment section" That section is not findable on the website.


Looked at the "chassis electrical" diagram for 2004-2008 BlueBird Vision buses. It shows, as I suspected, an ECU relay in play, powering the ECU and the dash lights, each separately fused. That still does not tell me which relay in my bus to check, or where the ECU is fused. The dash-lights fuse is 7.5 amps. Quite a bit for a few low-powered bulbs. By contrast the IGN-directional (turn signals?) fuse is 3 amps. So maybe the "dash lights" fuse also serves the ECU?


Many wires in my bus are "numbered," even though they are the same color. Found that the IGN wire at the switch has the same number as the one on the fuse, but with a different suffix, i.e. 1162B and 1162R. So circuits are identifiable that way. I bet the same basic wiring harnesses are made for different buses, to save on the cost of production.




Anyway I'll be spending the day pulling relays and testing for continuity to the "dash lights" fuse, and perhaps checking each relay individually for proper functioning.


Sure would love to have a chart showing what each relay is for.


Happy Holidays to all! I was planning to spend my day with the only true family I know: the woods and the mountains; the rocks, trees, flora and fauna of the highlands. But alas, I'm stuck in Babylon with money-grubbers and abusers. I need this beast to run, and the weather is nice today, good for working on electrical systems.


Peace - Love - Light - Aloha!

 

[Mountain Gnome]

Well I spent the afternoon yesterday pulling relays and checking for voltages. i pulled every relay out that I could find, all at once, and I still had 7.2V at the "dash lights" fuse. This was with the dash removed and the ignition switch harness (and all other switches) physically disconnected.



I also checked for voltage, especially at the relays' pin 30, and all was good, except 2 had only 7.64V. Pin 30 is supposed to be the battery power.



I assigned the relays my own numbers. There are two vertical rows (the pics in the previous post are rotated...sorry) in the relay gang, so I numbered them like reading a book: #1 in the top-left, #2 in the top-right, #3 under #1, #4 under #2, etc., so odd is on the left, even on the right.


The relays that were getting low voltage were #2 and #4.


So I still suspect that there is an ECU/ECM relay somewhere hidden, and it is bad. But where?


Either that, or a faulty connector that is corroded. I see fat wires coming off the "body hot" stud next to the relay gang in the hidden panel behind the windshield wipers under the driver's front windshield. But small wires at relays, etc. Where is the power distributed? Is it hidden in the wiring harness? I really don't want to destroy it just to probe it, without knowing. But I don't see the fat wires connecting to anything.


Today I'll probe the wiring harness connectors that I can see and reach, and try to find another wire with only 7V, and hope it offers a clue...


I'm also gonna call CentralStatesBus and see if they can help, since their website openly offers to help. But I bet they're closed this week...

 

[Mountain Gnome]

So last week I started checking random connectors under the dash for a low-voltage wire, as stated above. The first one I looked at was the big one. Found a 7.2V wire, and it had the same circuit number on it as in the fuse box and was the same color. Great!


Disconnected that big connector, and the fuse looses power. So that's the one...disappearing downward toward the hidden relay box. I went outside and removed the relay gang and its mounting bracket, as well as another piece of sheet metal that was part of the dash covering the hidden relay box, and was able to positively identify the proper harness by reaching up into the dash from under the front window to tug on the correct one, as there is 6 or more different ones (all wrapped in the common 1" black plastic flexible wiring conduit) all twisting together.


Then I shined my flashlight on that harness (set up to not move) and looked from underneath with another flashlight. Too far away, and too many harnesses, and too confusing. So I found a florescent pink pencil in the kitchen drawer (35+ years of collecting pens and pencils) and went back up to behind the relay gang and set up the pencil so it pointed to the correct harness. Then from underneath, I was able to positively identify the correct harness by another little series of tugs.


So now I had followed that wire inside its harness to under the bus, and after cutting a zip-tie, I followed the harness back to where wires started splitting off of it, just in front of another collection of 4 larger relays. I saw these relays before, but I ignored them, thinking they are part of the anti-lock braking system (one for each wheel) since they look beefy and are next to another enclosed box attached to the frame that looks to me like an anti-lock computer. But looking closer now, the wiring is not common to each-other on these relays.


At that point, it was getting late, and the car I borrow just arrived, so I'm waiting to see if one of these relays has 7V coming out of it. Rain and electronic multimeters don't go together. I hope I found it, because from there, following the rest of the harness gets even more of a PITA. Quite a bit more.


But so far, luckily, I haven't had to cut into a harness wrap, only one zip-tie!

 

[Mountain Gnome]

I climbed back under the bus today and picked up where I left off, following the wiring harness as it emerges from under the dashboard and behind the hidden relay gang. As I said, it then goes toward the back and wires start branching out. I grabbed the first connector, and saw it had a black wire with the same circuit number (11136G I think it was). Again, 7.2 volts found there. That led strait into the mystery-box bolted to the frame next to the front-driver's side wheel/tire, the one I guessed was for the ABS computer.


I opened the box (4 screws on the front panel, and it comes off) and inside was the power distribution! One big 200-amp fuse for the starter wire, plus another fat hot wire strait from the battery, and a fat ground wire that also goes strait to the battery. There are also two more fuse-holders in there, and an very small (2-circuit) electrical bus connecting the fuses to the wires leading out to the harness that I followed from the dash.


So I'm looking in there, and first notice the extreme corrosion on the screws in the electrical bus. I checked them with the voltmeter and found the same 7.2 volts. Then I noticed the reflection at the bottom of the box; I touched it and found water 1mm deep. Ah-HA!


So I disconnected the battereis, and started taking every thing out of the power-distribution box. The electrical bus fell apart. No biggie there. One of the "studs" that are used to connect the fat battery wires to the fuses cracked and broke off. Damn. That looks hard to find and replace.


Pulled the fuses out of the "water-resistant" covered fuse holders, and they were so caked up with corrosion, I can't believe any voltage got through them, but there was the cause voltage drop.


Found some new "water-resistant" fuse holders at the store this evening. I used some of those under the hood of my truck once. I opened the cover one day, and water poured out; it was in one of the dryer spots under the hood, and it blew my mind that it could fill with water. Moisture, a few drops, OK I can see that. But FULL of water?


Anyway the 2 new fuse holders don't have mounting flanges to screw them to the back of the box like the old ones. I plan on ditching the electrical bus and replacing it with shielded spade and bullet connectors (different types for the two different circuits, so they are more easily identifiable) then zip-tying the stuff to keep it from shifting around in the box. I'll goop up the connections with electrical circuit anit-corrosion-sealant. The computers need proper voltage (nothing kills electronics faster that a brownout) and that is why the connection was likely done with an electrical bus, since the screws hold so tightly, much more than a spade or bullet connector. But since I'm on top of it now, I know to keep an eye on it, and keep that box dry inside.


Anyway, tomorrow I hope to get it all re-assembled all the way back up to the dash; except that I might want to take this opportunity to add in 2 additional LED bulbs to the dash turn-signal indicators, bringing them up higher (top of dash) where I can see them better. So many times I've found them on, been on for miles and miles and miles.... unfortunately, the connector that plugs into the back of the dash-gauges assembly hides what wire is which, so that may be another hunt-and-peck game.


PICS:
(1) Air tank at top of pic, front of bus to the left, showing the collection of wiring harnesses that converge under the steering gear box. Most disappear up into the dash just to the left of the picture


(2) The four heavy-duty relays (I am still guessing they may be for the ABS?) are at the top of the picture. This is just in front of the front driver's side wheel/tire. Bottom left you see two 2-wire connectors, one disconnected, and one connected. The second has the power wire I've been following. In the top-right corner of the picture you can just see the power-distribution box for the computer(s?).


(3) A better view of the power distribution box with the heavy-duty relays in the bottom-left corner of the pic.


(4) the P.D. box

(5) can you tell there is water in the bottom of the box?

 

[Erik_Koning]

Was driving our 2007 blue bird vision home from a weekend gathering in the rain, stopped for a bite, turned bus back on and found that wipers and washer pump was no longer working.

Spent better part of an hour going through manuals and schematics on my laptop until it seemed it became obvious to head to the external access fuse box. The fuse box panel door had the schematic i needed! Why is it so hard to find that online.... anyway my wife turned on and off the bus as i felt the indicated solenoid for the wipers and sure enough it was not clicking. Took a hammer and rapidly tapped it as she turned on the bus and on first ignition it activated! Ive only seen that in movies so pretty fun thing to have work!

Note the fuse box wiring seems to be flipped vertically compared to the OP's.

Does anyone know why there should be two solenoids and not just one slightly larger one after the batteries?

Can i use the multiplex debug box to diagnose that solenoid was not working?

What other components are most likely to fail or become unreliable like this? Wondering what others experiences has been so we all know what spare parts to travel with?

Photos:

 

[nikitis]

Just seeing this post. I'm no expert at electrical on buses, however I've been researching it a lot lately, and I kind of can make sense of it generally.

As far as unlabeled wires, you are simply going to have to trace them to see what they go to which it seems you are doing.

But from what I understand is, in almost every bus there are three solenoids for basic starting functionality. (And a few relays for the ECM computers)

And anyone reading this can correct me if I'm wrong (Probably am and shouldn't be giving advice on this but want to learn as well so), but the first solenoid (One on your left in your pic) is related to triggering the starter sending 12v signal to the 3rd solenoid on the starter (the 3rd solenoid on the starter itself which is not shown in your pics). The 2nd solenoid (right side solenoid in your pic) which kicks on when the key is in the ACC position or post cranked position which is ACC. This as you can see visually ties into a breaker bar which all of the buses minor DC connections connect to like interior lights, instrument panels, etc and is in charge of any DC distribution for whatever the bus requires. Children stop lights wig wag lights, etc.

So once you kind of understand the basic structure all buses have, some are simplified as in your example, and others are cluttered with add-ons. If the electrical box is filled, it likely means there's a lot of additional add-ons it's powering up, so to demystify all of this, understand the basic circuitry then look at everything else as additional items not necessarily required for the bus to function at it's most basic level. (unless it's wired for child safety door checks etc to purposefully cut a circuit)

BTW, when I do fully figure all of this electrical stuff out, and I plan to understand it really well by the time I'm done with my bus build, I will make a forum post that someone not knowing anything about electrical can understand.