MC9 Air Dryer Heater Breaker Location

NewbeeMC9 · January 10, 2009, 10:05:40 PM

My MC9 does not have the Bus HVAC in it and apparently the power supply for the Air Dryer Heater comes off that system and is not working. I wanted wire strait to the breaker from the Bus Bar but the Breaker in Da- Book ain't like the pretty picture shows when I open my panel.

the panel shows a 10a breaker but the wiring shows a dotted line to a 3a one, I assume the dotted is an option.

Any of you eighter's or niner's had to deal with this and know where the breaker is?

buswarrior · January 11, 2009, 07:51:48 AM

Have a look for a single in-line fuse holder stuffed into the electric panel somewhere.

3 amp glass fuse is what you might find.

Yes, the heater was wired off the coach heat switch..makes some sense, if its cold enough to freeze the air drier, you'll be running the coach heat...

One of those little traps for those who strip the coach HVAC.

Alternatively, terminate what's there and run a fresh wire and don't worry about it?

happy coaching!
buswarrior

NewbeeMC9 · January 11, 2009, 08:41:47 AM

Aha!!!!! that was my next question when i got the camera going with picture added. It is there and the fuse is good. I was planning to do that and let the thermostatic switch do the job. It is in the same general area as the book but more aft.

Thanks BusWarrior, you saved me a lot of head scratchin and bald spot expansion.

I'm also going to bypass the drivers heat relay to and go strait to the switch to get the fans in the defrost fans to work, It is 14ga to 14ga and goes straight to the switch so it should be simple.

I will disconnect the drivers AC switch since I don't have that anymore and don't want it energized.

Thanks again, I love this board!!!

NewbeeMC9 · January 11, 2009, 12:28:52 PM

Here's what I have.

seems it is attached to a ground from the other relay through a Diode I believe and a 20 amp fuse is in there.

NewbeeMC9 · January 11, 2009, 12:33:51 PM

Here's a closer view, looks like a diode then holder to ground

I don't think this is the 3-amp fuse holder I was looking for.

buswarrior · January 11, 2009, 09:34:15 PM

Open up the panel, the hinge is in the picture.

Then you'll be cooking!

happy coaching!
buswarrior

NewbeeMC9 · January 12, 2009, 03:54:10 AM

I have looked in there but did not see fuse holder $:-\$ , I'll dig some more and post pics, the book picture of that area showed a 10 amp breaker there so I thought they maybe related.

For the defrost fans, I moved the wire from position 3(NO) to position 4(NC) on the Drivers heat relay and disconnected the Drivers AC switch, I now have defrost fan, Yea!!! A big win for me, a minuscule win for mankind.

One of those thing s you don't think about until you need it.

Thanks for the help!!!

NewbeeMC9 · January 12, 2009, 12:35:11 PM

Here's the wire panel, I followed Post 30 and it Has the yellow from the coach heat relay, and the two wires marked 54 and nothing else.

I'm scratching here now

NewbeeMC9 · January 12, 2009, 12:36:42 PM

Here is left side of page, I see where the diode to ground is now with the 20 amp fuse.

NewbeeMC9 · January 12, 2009, 12:39:23 PM

And the right side of Page from Da Book,

If anybody has seen something different.

NewbeeMC9 · January 12, 2009, 02:43:43 PM

Ok, I think a may have discovered something, I cant find something that don't exist.

I drove the bus up on blocks and the only place that wires could go to this dryer has a nice cleanliness plug in it.

There is no wire any where around it that looks like it may have been there before. My bus first life was for Continental Trailways in Mobile AL and if I'm correct had a regular run to Orlando and back so I think most kikely it was not installed.

Now I guess I have to find a plug? Any Ideas

Is the Thermostat built in to the heater element?

And a 3-amp fuse holder won't be a problem?

It is an AD-10 (or 9 it is heck getting old

)

JohnEd · January 12, 2009, 02:49:13 PM

KnuB,

You get an A+ for the best posed question I have ever seen. Schematics, observations and pics. Another big win for you! Thanks for the excellent example.

Sometimes understanding this kind of thing can be costly in terms of time. Maybe not this time but don't forget the Sage advice to "just give up" and run a new power line in there. Label it , of course.

HTH,

John

NewbeeMC9 · January 12, 2009, 06:32:38 PM

Thanks JohnEd,

I think I will run a new wire as soon as I find a plug for it. Hoping some body has an idea for the plug, and I'm fixing to look up the dryer to see if the thermostat is built in. Hoping somebody would know that to.

If you see the little tapes in the picture, that is where I have had to do some research and would label what found out.

I guess you have to get the Sage out when you run out of Thyme, that is if your turkey like me

NewbeeMC9 · January 12, 2009, 07:38:24 PM

I guess it has a thermostat according to the specs.

http://www.bendixvrc.com/itemDisplay.asp?documentID=4634

now to find a plug

John316 · January 12, 2009, 07:40:52 PM

KnewB,

If nothing else MCI would have it...Depending on the plug.

JAT

God bless,

John