MC9 dryer replacement question

[caz]

Original dryer blew up on me in a ice/snow storm last winter.  Freaking snow and ice in Dallas Did NOT see that coming...
I'm finally getting around to replacing the bypass hose, that was put in its place to get me moving, with a AD-9. The AD-9 is clearly marked for supply and delivery but I want to make sure I get the lines on the bus correct. Best I can tell by looking at the old dryer is that passenger side was supply and drivers side was discharge but the old dryer isn't labeled that way. The driver's side was the shorter line(upper section of the old dryer) connection and the passenger side has the longer(lower section of the old dryer) connection.
Also, am I understanding correctly that there is no +/- on the heater? Since the new connector has 2 black wires and the paperwork literally says, "Connect one of the two leads of the wire harness to the engine kill or ignition switch. The remaining lead of the wire harness must be connected to a good vehicle ground". Better to check and not let the smoke out 

Any help would be appreciated.

[caz]

Bump

Nothing? Anyone? 

[Utahclaimjumper]

The heater is just a small coil and doesn't care which direction the current flows thru it.>>>Dan

[caz]

Figured it was something like that, thanks for the info!
Anyone have any info on identifying which air line is which?  I already have it installed and I seems fine but for my piece of mind it would be good to know. With the check valve I assume if it's backward it wouldn't work. 

[Oonrahnjay]

(snip) Anyone have any info on identifying which air line is which?  

   I can't tell you for sure on yours but mine (which I know is different from yours) has a very detailed installation service sheet in the bendix service literature library.  Like you said, probably it's OK like you have it but I'd check to be sure. 

[buswarrior]

Run the coach engine,
the line that blows air connects to the supply fitting on the air drier,
the other one is the delivery to the coach.

Doesn't get simpler than that.
Too easy to screw up left and right when upside down under the coach...

And the rest of us can't remember correctly, within 3%, 19 out of 20 times...

Here's a thought for the congregation:

MCI wired coaches of this vintage with the air drier heater turned on through the coach body heat switch.
(which really screws up those who strip the coach HVAC out during the conversion and then get an air pressure disablement first time the coach is out in the cold)

Does a busnut with the coach heat stripped out want to wire the air drier heater direct, or does the busnut want to isolate the air drier heater for most of the rest of the year's operation via a separate switch?

happy coaching!
buswarrior

[caz]

Run the coach engine,
the line that blows air connects to the supply fitting on the air drier,
the other one is the delivery to the coach

happy coaching!
buswarrior

I'm like, duh...Genius I am, that never crossed my mind and this is why I'm here asking stupid questions 

As for the other question. My plan is to wire the heater to one of the unused panel switches so it's only on when I need it

[Scott & Heather]

MCI wired coaches of this vintage with the air drier heater turned on through the coach body heat switch.

Are you kidding me? Great. Strange how the advice always comes too late for me.    So now what? I have wire up a switch to it for use in the winter? Heather and I will likely be wintering next winter in a cold and snowy place...ugh. Add it to my ever growing list of bus projects.

[buswarrior]

Scott, the end of the wire resides in the compartment outside under the driver's window.

You will find a 3 amp fuse in a fuse holder on the wire.

It will be connected to the coach HVAC switch.

If you have terminated all the other stuff, try just turning the coach HVAC switch on, and check with your multimeter at the air direr to see if you get power.

It might be that simple, depending on how the rest of the equipment was removed/disconnected.

happy coaching!
buswarrior

[thomasinnv]

input line comes from the compressor/governor, output line goes to the wet tank above the front axle left side (driver side)

[Scott & Heather]

Scott, the end of the wire resides in the compartment outside under the driver's window.You will find a 3 amp fuse in a fuse holder on the wire.
It will be connected to the coach HVAC switch. If you have terminated all the other stuff, try just turning the coach HVAC switch on, and check with your multimeter at the air direr to see if you get power. It might be that simple, depending on how the rest of the equipment was removed/disconnected.

Excellent info...Thanks...so Caz, are you going to wire yours through the ignition then? So it's on all the time? Or add another switch? I think I'll add a switch since I would only turn it on in the winter. BusWarrior, the old heater switch etc is all pulled and gone. So I'll be looking for the fused wire and wiring a switch to it.

[caz]

Scott:  I have several switches on my side panel that power with the ignition switch but are no longer hooked up to any actual devices, so I'm going to hook it up to use only when I need it. I assume in the long run the heater will last longer that way as well.  My drivers area is yet to be touched except for the seat so I have lots-o-options 

[belfert]

The heater on the AD-9 is thermostatically controlled and only comes on below 40F.  I would wire it to an ignition switched line and forget about it.  Why complicate things with a switch you may forget to turn on in cold weather?

[Scott & Heather]

The heater on the AD-9 is thermostatically controlled and only comes on below 40F.  I would wire it to an ignition switched line and forget about it.  Why complicate things with a switch you may forget to turn on in cold weather?

If this is true, then problem solved....

[caz]

The heater on the AD-9 is thermostatically controlled and only comes on below 40F.  I would wire it to an ignition switched line and forget about it.  Why complicate things with a switch you may forget to turn on in cold weather?

Good to know. Less wiring to do now  Thanks!