Dash air fan

[Ck2hans]

Don’t know why, but reading electrical wiring diagrams just don’t come easy for me. After hours of studying I can make momentary sense out of them (which I forget as soon as I look away). Maybe we can have a seminar at one of the Prevost Expo’s for reading electrical diagrams for dummies.

Chuck

[GarfieldGuy]

Yes I did. After a follow up call with PASS this am they told me the same thing you did. I'm going to take a look at the dash controller this afternoon to see what voltage is coming out of it. Regarding the defrost air continuously blowing air, there is an access door "detail E" on the defroster installation page Y2-2230-00 of the parts manual that opens and closes via an actuator that over time will become detached from the actuator pin. To access from the top requires removal of the majority of trim on the drivers and passengers side. It would require alot of unplugging and replugging of a ton of connections. The alternative method is to remove the front right panel that contains the back up camera and A/C switches. That exposes the actuator and sliding door. They said to start by drilling a quarter size hole above the motor where you should see the dedicated allen screw that may be loose or gone. Then patch the hole. I'm going to start there and see if I can fix the problem.

[Hoffman]

One thing that I didn't see was to explore and confirm there's no blown fuse. I'm thinking of a fuse that controls the step motors on the baffles. My guess.
On my coach, CB79 is labled "DRIVER'S HTR FAN SPEED CTRL MODULE".
A guess.?

[Fratto]

The sample wiring diagram that I posted shows CB79 powering the defrost fan motor but as I understand it, the fan does run. It does not appear to have anything to do with the damper motors though. They are shown to have power from CB28.

It is easy enough to see if these or other breakers are tripped and to confirm that there is voltage coming to and leaving the breaker. Sure doesn’t hurt to confirm this.

Need to confirm all of this though with a diagram specific to his coach.

[GarfieldGuy]

PROBLEM SOLVED!!!!!
I physically followed the 64B wire (fan variable speed) from the blower fan in the dash to the drivers bay and the C11 pin connector bundle which is where I thought it was buried with a thousand other wires. As It turns out, it was not in the bundle but on it's own dedicated wire that was hanging by it's self. I saw the wire previously but didn't want to start chasing another issue until I found the 64 wire. Sure enough, when I looked at the wire label it said 64. Some more fishing around and I found the other half that had become separated from the clip connection which I still can't figure out does. There is no fuse in it. Reconnected the wire and fan works normally. All together the repair cost 600.00 for a new dash control head that I didn't need and 350.00 for a drivers fan speed ctrl module that I didn't need either. At least I didn't have to pay 160/hr to have a prevost tech trace down the problem!

[Fratto]

Nicely done! Glad to hear you got this resolved and are starting the year out on a high note