Where is the Road Light Relay located. It is NOT( and nor has it every been) in the Front Juntion Box as shown in the MCI-9 Manual, page 7-62.
The side light/marker lights are not working. I have power across the 15 amp Marker Light breaker.
The side turn signals work fine.
Thanks for the help....
Bill
If you have power
across the breaker, then the breaker is defective. You should only have power from each side of the breaker to ground, not across it.
Richard
Quote from: Kwajdiver on March 04, 2007, 09:36:41 AM
Where is the Road Light Relay located. It is NOT( and nor has it every been) in the Front Juntion Box as shown in the MCI-9 Manual, page 7-62.
The side light/marker lights are not working. I have power across the 15 amp Marker Light breaker.
The side turn signals work fine.
Thanks for the help....
Bill
Richard,
You are correct,,,,, sorry, I have voltage, breaker to ground.
Bill
My diagram shows the "road lights" relay is dashed around it. which means you may or may not have that option.
My MC9 does not have a road lights relay. it is wired direct through the toggle switch for ID Lamps
and a second leg from the HeadLamp switch.
A guess would be that you have a bad toggle switch or loose wire in the side panel. Or maybe the side panel has
lost it's ground to chassis. Mine did and I hade to re-ground the aluminum panel to the frame with a # 10 wire
to get my dash lights and relays to behave.
If there is a relay it should be in the side panel and available from outside access cover.
The tail light/clearance light relay for my MC9 (87 ex-NJT) is in the LH lower electrical compartment. Right beneath the horn relay. It controls the pax interior, isle, tail, dash, driver, step, and clearance lights.
As you state, there are several optional formats...but the lower section of the electrical junction box is where the "road light" lighting relay is located.
Mine is definitely located below the horn relay.
It is not located in the upper enclosure...it is visible once the exterior door is open.
It's possible that the NJT layout is different from other MC9s...they had their way of doing things!
Let me know if it would help and I'll go down tomorrow and see exactly what it looks like. I know it has prox 8 wires going to it. Plus the two bus bar leads.
JR
My headlight relays are below the front breaker panel == alongside the driver's water valve, but this may not be standard.
While on the subject of hidden relays, my MC8 has a couple of relays buried under the instrument panel between the steering column and the front of the bus. Anyone know what they do -- or even if they are standard?
Tony
Bill, I see you're describing the marker lights...does any other lighting work? Headlights, tail lights? Dash lights coming on?
The headlights have a separate relay. I assume that these are working?
More details.
The sidelight turn signals are off of a separate circuit.
If you attach 24V lead to any clearance light center contact (not the ground contact), you should be able to backfeed a signal and follow the wires in the FJB.
I'll let you know what the relay looks like tomorrow. Someone may have modified something..or stolen the relay. It's a nice heavy thing.
Have your ID lights ever worked?
JR
Guys,
I have a manual, I do not have a relay mounted under the horn relay. However, I do have a round thing with three connecters floating around, not sure what that is, it's round and heavy.
Headlights, turn signal, dash lights, brake lights, all work. I have a voltage drop to the headlights, but that is a different problem. Headlights are only getting 8 volts to them, but I'm working on that.
The manual shows a connections after the relay, that I don't have. I need a check point after the panel mounted switch. There must be something else, before the lights.
Bill
I took a look today at my marker light relay....just as I thought, it's immediately beneath the horn relay...lower frontmost in FEB. Must be an NJT special...big expensive looking sucker.
However, the manual that I have also shows an MC9 system without the relay. Have you applied 24V to terminal 15 in the FJB? That's the terminal that is directly energized by the clearance light switch. If this terminal is hot, and I believe it is due to the dash lights working, the wiring in the immediate area of stud 15 is likely faulty. Appears the dash lights also are powered by the #15 stud so you may have another issue. If your dash lights are working, some of the system is operating. The dash lighting is part of the marker light circuit.
Has any wiring been cut out of the front of the coach during the conversion? The upper center light wires are famous for being inadvertantly removed.
This wouldn't explain the total lack of marker lighting.
My guess is that the problem is inside the electrical compartment, upper section, related to the wiring on term 15. Or all your marker lights are burned out.
There is also a terminal in the RJB, #3 that is the rear marker and tail light stud. It gets power from the FJB stud 15.
Hope your bus hasn't be "rewired" to suit (or solve) some other problem.
You've probably figured this out, but the marker light wire # is 15 Red/Blue. That should be visible in the upper electrical compartment. That's the lead that feeds the marker lights. Straight off term 15 up to the front cap.
does your bus have aftermarket caps on it? May be missing grounds (white wire) or some such thing.
Did your marker lights work when you bought the coach? If they did, what has been done inside the electrical box since? If they didn't work, well.... ??? As the DDEC manual sez, "you have made a diagnostic error, recheck"
You are also probably aware, but both front and rear marker light leads split off at term 15 in the FJB...so the problem must be very close to that terminal, or between said terminal and the switch. Center marker lights are supplied from the front markers. Lower side markers are turn signals only.
JR
JR,
Yes, they did work. I have been replacing sockets on the bottom lights. Guess I started to replace bulbs when I thought the bulbs were the problem, then found the sockets were in bad shape, now the sockets are new, bulbs are new, and no lights. Turn signals work, so I know the sockets and bulbs are good.
I will look around term #15 and start from there.
Thanks for the hint.
Bill
There are no bulbs or sockets that share turn signal functions. The bulbs in the turn signals are dual filament/dual contact, but they have only one function...example: front turn signals and side marker turn signals. Only tail, tag and upper marker lights are on the marker light circuit. TBOMK, none of these are dual function sockets.
The lower side lights are not maker lights...they are turn signals only.
The turn sig bulbs are oddities...be sure and replace the TS bulbs with the correct bulb number...unless the system has been modified. The dual filament turn sig bulbs ground thru the contacts and are not grounded thru the base. OEM marker lights are also grounded thru the contacts.
The above assumes that your bus has OEM style lighting. Aftermarket lighting may be otherwise.
Best, JR
JR.
JUMPBACK,,,,,,,,, ??? Okay, the bottom four lights, two on each side of the bus........THEY ARE TURN SIGNAL ONLY........??????????? If this is the case, then they work..... For legal reasons, don't I need some type of lights on the side (bottom) of the coach....... :-\
I have eight turn signals, two on the front, two on each side and two on the rear. Baby they will see me turning.....
Don't think my upper lights are more than a bulb problem.
Sinking Fast and Still in Little Rock,
Bill
Yep. I'm pretty sure the lower side lights are turn signals only. When looking at the schematic, what they are calling "side marker lights" are the two upper sides on each end (2 each). The front and rear center 5 are referenced as "clearance lights." The upper center sides are called "intermediate" marker lights.
Someone could have installed working lower side lights...but that ain't at all likely. The dual filaments will screw with your mind. Use the numbers listed in the manual for replacement bulbs...they are "$pecial." ;) Same is true of your front turn signal bulbs. They are not similar to automobile lights.
TTBOMK, there are no "dual filament" "dual circuit" bulbs (with exception of the headlights) on a bus. All bulbs for road lights are single circuit, yet may have two filaments. Failsafe I reckon? This is what I've seen on MC9s. Not familiar with any other coach.
You should have an amber reflector on each front side corner, two ambers in the center of the side bay doors, and two red reflectors on the rear side corners. That's it.
I believe trailers must have working lower marker lights.
If you wish to proof the side lights, remove a bulb and put an ohmeter across the contacts. Bet you find both filaments are connected. Only one circuit will be apparent.
Be very careful if you attempt to remove one of those lower side lights. The wiring is easy to damage and hard to repair.
Best, JR
JR,
Thanks for all the input, looks like I'm in good shape, at last.
Now the headlight problem....... :(
I don't have the manual in front of me. On the headlight relay located in the FJB, I need to know what voltages you have on a couple of the pins. Need my manual to ask what pins. I'm only getting 8 volts to my lower bean highlights. Haven't gotten very far into the trouble shooting.
Bill
That don't sound like quite enough voltage. Keep in mind that there are two headlight circuit relays. The forward unit is the 24V relay, and the next one to the rear is the 12V relay. They are both controlled by 24V.
If one of your headlights burn out, the 12V feed system will supply voltage to the remaining light. A set of diodes prevent backfeeding.
Also keep in mind that the headlights are wired in series (if you still have the 24V system supplying 12V headlights).
This is a complicated system. I'll have to get the book out once you form a question on a particular pin....
Are your batteries up? You may be reading the low center tap voltage.
Center tap should be 12V, but maybe the batts are down.
Waiting for your question! ???
Best, JR
JR,
Headlight Relay pin outs. Battery is charged.
Normal Brights On
1 12.2 0
2 26.8 10.5
3 12.2 3
4 12.2 10.5
5 .17 10.2
6 12 4.4
7 0 0
8 12 10.3
Uh... Hmmm...
It sounds like you have a dropping resistor in the headlight circuit.
If so it should be located in the lower accessory air tank compartment
up on the far left inside the curve of the sheet metal.
If it is a resistor it is probably bad. I had seen one other MCI that had
12 volt headlights and instead of using a 12 volt tap from the battery
they installed a load resistor in the headlight circuit and that's where we found it.
Now.. Let me clarify.. This information is only provided because for some strange
reason it seemed to ring a bell in my feeble brain. I don't remember where I saw this
nor whether it was an MC7 or 8 or early MC9....
I could be completely wrong too.. Maybe it was something else.. I dunno...
Dave.....
Which relay are you pinning out there ?? is that the headlite on or headlite hi lo relay???
This is gonna get complicated...but here goes.
The headlight relays are only for switching high/low grounds and the 12V backup system...they don't "supply" headlite voltage in a "relay" sense. The headlight power comes from the headlight switch. But, the ground is managed by the front "high beam" relay.
Pin 3 is switched ground, but it grounds by connecting the RH headlight to the LH in series. On high beam.
This all assumes that your system is OEM MC9 with the 12V headlights in a 24V system. They are wired in series. So the readings you get on will vary by pin. Pin 4 and 5 complete the low beam circuit, and pins 3 and 6 complete the high beams. Pin 1 grounds the relay coil, and pin 2 is high beam call. Pin 2 is the only pin that would have 24V, and only then on high beam. If the bus is correctly wired, pins 3,4,5,6 would have the resistance of one (or two filaments on high beam) headlight assembly.
The high beam relay is making grounds, not the power source.
As Dr. Dave suggested, someone may have modified your headlight system to operate similar to a truck. 12V to each set of filaments with a ground on each headlight.
If you pull the LH headlights out where you can access the plug and check for 24V on low and 24V on high beam (only the LH headlight). The readings should be 24V on both. Check for a good ground on the RH headlight. This is a common problem point. Keep in mind, the headlights if OEM, are wired in series. The 12V cut relay will power up the remaining headlight if one filament burns out.
If you find 12V on the LH headlight low and high leads, the system has been converted to 12V. Probably.
Stud 28 in the FJB is the headlight supply and should read 24V on OEM wiring.
If you have factory fog lights, the headlights must be in "headlamp" position to operate.
The factory headlight system is complicated.
What exactly is your problem with the headlights? If one unit isn't working, the 12V backup is powering the remaining headlight. This will confuse the H out of diagnostics. If you have a bulb burned out, or removed from the circuit, the system will go into 12V default....should.
Before you go much further, clean up the grounds and the 5 stud block that the wires are connected to. Be careful with the diodes. This assembly is right beneath your left foot, in the tool compartment.
Now I'm confused.... :-[
Now I'm gonna say something that will get attention....If my headlights circuit failed, I'd wire it similar to a big truck. No backup crap and all that complicated wiring. The only issue is having to center tap the batteries for 12V. Gotta have an equalizer....which I do. That system would be as dependable as the aged bus systems. These things can and will fail. Your your own guy, so what ever suits is good. Just something to think about. Do a nice wiring job, the 12V supply is at the 12V cut relay, and in the AC box. If you get your headlights working well, no problem, but if not, well, that's been described above. Some of our old buses have had mods to the headlight circuits and that should be considered and perhaps improved if necessary.
Good luck dude! JR
I also might comment that the headlite system goes through the upper switch panel and has plugs to it that might get bad contacts as well as high resistance switches. Jerry
Quote from: Kwajdiver on March 08, 2007, 02:39:08 PM
JR,
Headlight Relay pin outs. Battery is charged.
Normal Brights On
1 12.2 0
2 26.8 10.5
3 12.2 3
4 12.2 10.5
5 .17 10.2
6 12 4.4
7 0 0
8 12 10.3
There shouldn't be any voltage on pin 2 unless the high beam headlights are on.
The pin 4 and 5 may indicate a bad relay. If you're measuring to a good ground, 4 and 5 should be the same. Otherwise, what you have on the High Beam relay looks almost normal. The 4/5 thing should be rechecked. Reading on 4, should be present on 5. When 24V is on pin 2.
May be some resistance in the contactors. I'd replace that relay.
Looks like the voltage supply is funky on high beams. Still you are showing voltage on pin 2 which should not be there on low beams.
I chew on this for a day. Bedtime for Bonzo.
Have you checked your dimmer switch? They can be problematic.
Get back from the relay and see if what is supposed to be present is measurable at another location?
JR
JR,
Thanks for the input and the time. I will check all in the next couple of days. Have been thinking about the dimmer switch. I know they can be a problem.
The dimmer switch is located of course, left side near the front. What is the push button, looks like a dimmer switch, left side on the floor next to the driver seat?
Driving down to Hot Springs National Park for the weekend. Never been there, looking forward to it..... I will check the voltages while there.
Thanks again,
Bill
The dimmer switch is nothing bu an off-on switch. it is off when lights are dim and on when on bright. What is does is power the hi low relar in the bright position and the hi low relay just makes the series connection to the headlights. Pin 1-8 are the 12V center tapp of the headlitss and are fed 12V from the center tap of the battery to insure proper operation keeping the lamps balanced and providing a path for an operation light if one in series fails.
Jerry
Hi Guys, I'm back....
Had to take a little work trip that was to be one city and two days. Three cities, Saginaw, Mich, Champaign, Il and Atlantic Ciy, NJ and I'm back in Little Rock in the bus.
Have been working on the head light problem. Cleaned all connection on the bus bar under the driver side lower panel.
On the relay, with no load, (wires removed on 3,4,5,6)
I read,
pin 3 12 vdc
pin 4 0
pin 5 0
pin 6 12
Note Pin 2 is still reading 26vdc. No matter what the state.
All other voltages are still the same, as when I started.
Should I order a new headlight Relay, where is the best place to order such an item.
Bill
Hey Bill, I don't have an mc-9 but it looks or sounds like the wiring is all about the same. As a mc 96 shows that pin 2 is the relay coil so that would indicate that the relay is activated.as long as pin 7 is ground. When in that mode then pin 4 and 5 are zero. so that would be correct. therefore pins 2 and 3 are powered to run the headlamps and are in contact with the 12 volts on pin 1 and 2 so what next as this should mean the high beams are on. Jerry