simple wireing question

Rodsmc5c · November 21, 2006, 06:13:37 AM

In my mc 5c, a previous owner had removed the air handler i assume and ac stuff from the front storage bay. After fooling with testers for about a week trying to get my tail lights to work, I found a branch off of the main front to back cable in the air handler area with about 18 wires that had been sawn off !!! I found the wires to the tail light amoung them. where do the rest go? Was there a box or control panel or something there ?? I have the maintenance manual, but I don't find it in there.
Thanks Rod

JackConrad · November 21, 2006, 06:33:47 AM

Not sure about a MC-5, but on our MC-8, There is an Air Conditioning Junction Box in the area you describe. The wires inside this box include Turn Signals, AC/heat circuits, and baggage compartment lamps. Left turn wire is yellow, 16 gauge, #44. Right turn wire is yellow-red, 16 gauge,#45. MC-5 may be different. In our MC-8 manual wiring schematics, the AC Junction box os noted as a triangle with the "point " up. Hope this helps, Jack

FloridaCliff · November 21, 2006, 06:45:33 AM

Rod,

I know you will need the wiring diagram to really find out where everything goes too!

On my GMC there was a bunch of unused wires after the a/c was removed.

Might I suggest that you terminate all of these and find out where they go, it is really nice to have a spare wire to use should you

have a problem or be able to eliminate the wire as the cause of a problem.

The a/c compartment wires probably run to almost every location, great spares to have.

Best of luck,

Cliff

Jeremy · November 21, 2006, 06:57:29 AM

Bear in mind that some of them may go nowhere - I've found hundreds of feet of 'spare' cable in the roof of my coach - the wiring loom fitted when the bus was built had to incorporate every possible option and version of the vehicle, so there will almost always be redundant wiring in any individual bus. Having said that, I expect it's less true of older or more unusual buses, which are more likely to have been wired 'by hand' rather than using standard looms.

Jeremy

Rodsmc5c · November 22, 2006, 05:49:32 AM

Thanks guys
I already found the the tail lights in that bundle, I am still looking for the fuel gage,perhaps the dash or drivers heater fan, back-up lights,maybe some of the heat switches in the drivers control panel, stuff like that. Thats why I was wondering if there was a box with lugs or relays or something like that.
Thanks again Rod

Len Silva · November 22, 2006, 06:08:16 AM

Rod,

Pick up a cable toner/tracer (here's an example: http://www.action-electronics.com/tracker.htm#Toner). They are all over ebay and even at Home Depot. $65-100

This is the easiest way to find conductors in a harness, trace hidden cables and wires behind (non-metalic) walls etc.

You just connect the tone generator to one end of a known conductor and "sniff around" for the other end, a very handy tool for working on busses.

Len

gumpy · November 22, 2006, 06:44:53 AM

Quote from: Len Silva on November 22, 2006, 06:08:16 AM
Rod,

Pick up a cable toner/tracer (here's an example: http://www.action-electronics.com/tracker.htm#Toner). They are all over ebay and even at Home Depot. $65-100

This is the easiest way to find conductors in a harness, trace hidden cables and wires behind (non-metalic) walls etc.

You just connect the tone generator to one end of a known conductor and "sniff around" for the other end, a very handy tool for working on busses.

Len

I don't know about these, but I bought a less expensive one from Home Depot a few years ago and tried it on my bus. Big waste of money. I could not trace a single wire from the front to the rear. I even stretched a new wire from the front junction box to the back, and attached ends directly to the studs in the junction boxes. The tracer would not work. Never did figure out why. Just returned it and got my money back. Haven't tried one since.

eglluvr · November 22, 2006, 08:56:06 AM

Quote from: gumpy on November 22, 2006, 06:44:53 AM
Quote from: Len Silva on November 22, 2006, 06:08:16 AM
Rod,

Pick up a cable toner/tracer (here's an example: http://www.action-electronics.com/tracker.htm#Toner). They are all over ebay and even at Home Depot. $65-100

This is the easiest way to find conductors in a harness, trace hidden cables and wires behind (non-metalic) walls etc.

You just connect the tone generator to one end of a known conductor and "sniff around" for the other end, a very handy tool for working on busses.

Len

I don't know about these, but I bought a less expensive one from Home Depot a few years ago and tried it on my bus. Big waste of money. I could not trace a single wire from the front to the rear. I even stretched a new wire from the front junction box to the back, and attached ends directly to the studs in the junction boxes. The tracer would not work. Never did figure out why. Just returned it and got my money back. Haven't tried one since.

I wonder if you guys are talking about the same kind of tracer, I used "tone Generators/Continuity testers over hundreds of feet in telephone cable. In the continuity mode, it is oretty much a 2 person job, but with the "Working" tone generator, and a good inductive amp, you should be able to identify the conductors easily. One note of caution on diminished tone though....The tone will jump an open conductor, but it will be attenuated significantly. Anybody need more info, some of the best were/are made by progresive... 77m (Toner) & 200b (Inductive amp)

If you ever get bored, Play with that inductive amp in Your telephone backboard, and you can see why i distrust most "Bug Finders" who needs a connection to listen to anything, even when your phone is on the hook, at times"

Jim

Instilling telephone tapping paranoia since 2006

belfert · November 22, 2006, 09:07:12 AM

When I built my house, I ran network cables from all over the house to the utility room. The labels I put on the cables mostly fell off.

I tried one of those wire tracers from Home Depot, but the signal is so strong that it was hard to figure out which cable in a bundle was the right one. The buzzer would go off on multiple cables in the bundle.

Brian Elfert

eglluvr · November 22, 2006, 09:40:04 AM

Quote from: belfert on November 22, 2006, 09:07:12 AM
When I built my house, I ran network cables from all over the house to the utility room. The labels I put on the cables mostly fell off.

I tried one of those wire tracers from Home Depot, but the signal is so strong that it was hard to figure out which cable in a bundle was the right one. The buzzer would go off on multiple cables in the bundle.

Brian Elfert

Brian,
If they were network cables (CatX) and you had that much induced noise from the tone generator, i think you have others issues.... For future reference, I always mark both ends of the cable when I start my runs, Both at the end on the sheath with a "Sharpie" and a few feet back, In case I exceed to 10lb max pulling tension by a few hundred pounds, and rip the end of the cables off....

I also used to use the wiremarker lables, but they are poor, especially if used in conduit. But you can tape over them when you attach your pull line, and this keeps the tags pretty safe. Also with network cables, Just terminate the cables and throw a cheap cable tester on them. Checks terminations and wiremap, and lets you identify the cables quickly.

FWIW/HTH

Former cable ape extrodinaire

Jim

Jim

Dale MC8 · November 22, 2006, 10:56:42 AM

Hey Rod, if your MCI is like mine, you might fish around alongside the front of the fuel tank and come up with an unconnected wire that goes to the dash for the fuel gauge.

On another note, I read somewhere that a good/fast/cheap wire tracer can be made from a transistor radio with an earphone. Cut one wire of the earphone lead and add wire w/alligator clips to each end of cut wire. Find a good strong station, plug in the earphone [to the radio and to your ear], attach a clip to a wire and use the other end to probe wires at the other end of the bus. When you hear music, thats the one.

HTH

Dale MC8

eglluvr · November 22, 2006, 03:19:43 PM

Dale, Do they still make transistor radios?!?!?

Dale MC8 · November 22, 2006, 05:13:13 PM

I don't know, but look in a thrift shop

Dale MC8

Rodsmc5c · November 23, 2006, 07:40:32 AM

transistor radio ? heh heh, that was a good one. I did make a tester out of a 24 volt lamp socket with a long piece of t-stat wire and aligator clips on the other end. that worked well for the tail lights. I also found a wire next to the fuel tank , will have to chase that one out. what made me wonder about a box is the way the tail light wires were run, it came out of the main cable, went to the light, went back to the main cable and on to the rear of the bus in a different wire. It just seems to me that there should have been a terminal there some where.
Rod

jjrbus · November 23, 2006, 10:17:22 AM

Rod, in my 5C maintanance maual on page 7-38 it shows the AC junction box codes. If you do not have it let me know. it shows the fuel gauge as stud (which you dont seem to have) 13, there may be metal collar on the wire with the #53 on it. the wire is black/blue 16 ga. It should go to stud #35 in the front junction box!