little dash heat & heater core access for 2003 Marquis

[Sean L Harrington]

2003 Marquis Ruby
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I have very little heat coming out from the dash (comparatively little compared to my ‘97 Newmar Mountain Aire).

I do not see any valves near the engine or discussed in the manual.

I plan to start by locating the heater control valve to see if it’s faulty.  Does anyone know: is this electric or vacuum operated, and where might I locate the heater control valve and heater core (if in a different location)?

Note, I do not see a removable panel on the front cap, although it’s currently covered by a front bra.  I only have the generator pull out, and I do not see any additional access to anything with the generator out.   I can see a little bit from under the front cap, but it’s not reasonable accessible by an average-size person.

I have removed the dashboard covers and have possibly located the factory heater core opening suggested by Gerald Farris in another thread.  I have posted a photo of that here, and wonder if anyone can confirm that’s what it is.  I plan to clean the heater core of lint if I can access it, but I am reluctant to remove the two bolts and steel plate visible in my photo, because they appear structural (as if they are there to hold something heavy in place).

If anyone has been into this, please advise.

[Steve Huber Co-Admin]

Sean,
The heater control valve should be located on the front firewall on the passenger side and should be accessible when the geni slide is out. It is vacuum controlled.
Steve

[Sean L Harrington]

Hi, Steve. Unless I’ve misconstrued something, it doesn’t seem to be the case in my Marquis. Immediately above the generator is a finished “ceiling.” Because it’s only a few inches above the top surface of the generator, I couldn’t get a good photo. I see a large line or two that are enclosed in a jacket or casing, but no valves, no heater cores, no vacuum lines, and no space to reach up, work, or do anything.

[Steve Huber Co-Admin]

Sean,
There should be space between the front cap fiberglass and the front side of the firewall. The reason for extending the geni is to allow access. The area I'm referring to is to the right of the geni, not directly above it.
Steve

[Sean L Harrington]

Thanks again, Steve. While I had the generator out, I also snapped photos of both sides (attached hereto). The driver side has two large rubber lines that, perhaps, could be the coolant and return lines, but no apparent control valves or access or even visibility to a core.

[Steve Huber Co-Admin]

Yes, the 2 large hoses are probably the coolant feed  and return to the heater core. One of the small diameter lines may be the vacuum line. You may want to call BCS and ask them where the heater core on your coach is located or maybe (hopefully) someone here on the Forum with a coach like yours can help. Like I indicated earlier, I had a shop change my core as I saw no way to get to it.
Steve