Trying to get my headlights to work on the bus.
I have clearance light that work.
Having trouble with the headlights
Need to re wire them. One wire should be ground, one wire low beam and one wire high beam.
I have all three wires to the headlight hot.
Even thoe I only have one wire hooked up.
Help please.
Probably a failed hi/lo switch, they do not last. If it is no that, run new wires, on mine the old wire's casing had frayed and they were shorting to each other.
Get used to using your multi meter, repairing stuff, you have an old bus.
I don't have any experience with a bus of this type so it may not apply, but some older buses had a wiring system that used 12V headlights in a 24V system. There are two problems with this ... when they don't work, it's sometimes hard to find problems because those systems don't follow "usual" rules -- you have to know where to look for 24V and where to look for 12V; the other problem is that by now they have often been "repaired" by someone who doesn't really know what he's doing and you get all kind of weirdness.
As Zub said, you have to take your meter and go back to basics and trace. You do have a wiring diagram, don't you?
All I have is the maintenance manual.
Yes, there has been some work done by others
Much of this wiring look original, but some has been changed.
I would love to get the wiring diagram that the book calls for.
MD-75571 is what the manual calls it.
Unplug the headlight and test the elct, connection with a test the light. Ground the test light on the body,grill ect. and turn on headlight switch and determine which wire is low beam and which is high beam and the third should be ground. usually it is the ground you are missing. Be sure to unplug both headlights for test to work.
10-4
Later this afternoon when I get done working.
Someone here or at the yahoo gmc buz site? Has a PDF of the shop manual that includes a wiring diagram. It is free ask around.... Your manual had a diagram at the back when new.
Headlights should be separate from marker lights and on small metal circuit breakers. Check to see if breaker is bad.
The 4104 was all 12 volt, no 24 volt involved. They were originally positive-ground, may be converted to negative-ground. That's not an issue, don't let it confuse things.
Thank you PENNUJA
Got it.
OK, clearance lights when you turn them on, come on then you here a clicking sound coming from the panel on the left side of the driver.
Some sort of relay. Clicks again and they come back on. Looked at the wiring and it is old, and crack all over. Wiring in the panels on the dash and too the left
look good. Only a couple of newer looking wires. One run too the headlights. So i know now that the wiring for the clearance light has to be replaced. Now I need to find out how (where) the wires run. Do I have to pull all the cabinets down or what?
On HUGGY you have 2 different toggle switches for the clearance lights and the head lights.
By the way a 04 is all 12 volt no fancy wireing for the head lights needed.
Hot wire to the dimmer switch and a wire to the dim and a wire to the bright side.
uncle ned
Thanks for the 12 volt.
Working on it this afternoon
Quote from: 4104SoFl on October 13, 2015, 01:52:56 AM
OK, clearance lights when you turn them on, come on then you here a clicking sound coming from the panel on the left side of the driver.
Some sort of relay. Clicks again and they come back on. Looked at the wiring and it is old, and crack all over. Wiring in the panels on the dash and too the left
look good. Only a couple of newer looking wires. One run too the headlights. So i know now that the wiring for the clearance light has to be replaced. Now I need to find out how (where) the wires run. Do I have to pull all the cabinets down or what?
the click is the fuse tripping, they reset automatically, then trip again. Find the PDF of manual to wiring diagram. The panel by the drivers seat is the front Junction box...might as well open it, and leave it open til you work it out. I ended up just running fresh wires to all the clearance lights etc as most were shorting to ground. Fortunately other than lightning most of the 04's wiring is fairly straightforward.
I believe this to be true.
Someone from the board was kind enough to send me the missing pages to the manual. I was missing the last 30 or so pages.
My question is how do I rewire. I pulled I cabinet down on the right rear. Still could not get to the wires.
So please tell me how I get to these wires?
'scuse my ignorance: what's a PENNUJA?
Ted.
I thought it was the name of the person who sent me the manual.
Running new wires to the marker lights is difficult. I would start by taking the lens off marker lights in seeing if the short is that actually in the light socket. When you do have to run new wires I believe the rear wires join up at the rear panel . if you are running the wires you have to take the lens caps off which is difficult anyhow so might as well start there.. Certainly some of the shorting may just be a socket or whatever having shorted out, not all my wires were bad, I just replaced what was bad. FYI the marker light wires were not accessible when the bus was new and are even less so once converted. Best bet is to find one end and pull a new wire with it. If not, discreet holes in cabinets etc may be required.
When I first got our 4104, I looked at the front and back panels and almost had a heart attack. There were literally over 100 cotton wrapped wires going to the distribution panel - 90% had no function anymore and all were a fire hazard. I gutted the front panel, preserved the original 3/0 primaries from the start batteries. I installed three 12 post fuse blocks (two hot all the time and one hot when Engine On is switched) wired to the primary, and rewired everything. Also did the same for the rear panel. Tore everything out and replaced with modern electrical components - 4 relays (engine on, reverse solenoid, high idle, and starter) and a 12 post fuse block wired hot from the existing 3/0 primary from the start batteries. Since I had gutted the bus, I a ran raceway down the driver's side to the engine bulkhead and also across to the rear electrical panel.
If you're starting with a fully built-out interior, I'd see if there is a way to install a raceway (4" PVC maybe) even if it's in short pieces from front to back in the back of cabinets, etc.
You can get to the upper and lower markers only from the outside. Remove the lights and drill through the wall/ceiling. Pull the wires through and run to the front panel. Be creative and you can hide the new wires without it looking cobbled. Use #12 DC stranded wire and you shouldn't have to worry about overloading. Do this one circuit at a time. You can have an all new system that is safe and one that you understand completely. Label all wires, fuses, circuit breakers and relays as you go.
before you rewire make sure some one didnt put a single pole bulb in a double pole socket. side lights ussually.
ZubZub: Took r/r lens and then the entire light off. Wires are bad. Still tring to figure out what I'm going to do.
Gordie Allen: Thanks for the good, smart advise.
Jachhanoe: It is the wiring for sure.
i would get some liquid tape and colored electrical tape and carefully reinsulate the wires most likely the wires are good where they havent been disturbed. the liquid tape can get messy. but ive used it on cars and trucks from the late eighties through late nineties because the heat and oil get to the insulation and some times you can just get in to the broken part without removing a major part. just make sure there isn't any oil on the wire first.
Quote from: jackhanow on October 18, 2015, 07:38:04 AM
i would get some liquid tape and colored electrical tape and carefully reinsulate the wires most likely the wires are good where they havent been disturbed. the liquid tape can get messy. but ive used it on cars and trucks from the late eighties through late nineties because the heat and oil get to the insulation and some times you can just get in to the broken part without removing a major part. just make sure there isn't any oil on the wire first.
.
I agree with this to a point, but on an old 04 the wires casing is so crumbly they will short inside a conduitbwithout movement. By all means, try the liquid tape etc...see if it is s I'll shorting...
Another thought, replace the bulbs and socket with led stuff, this will reduce the load (maybe hide a problem) but you will also not need to go back. Led sockets are affordable online.