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2000 XL 40 Marathon- No chassis dash heat
From buying our coach August 2015, to traveling to Quebec last Fall, to Vonore also last fall, and Indio California and back home before Thanksgiving, coach’ dash ventilation operation has been flawle.
Much to our surprise, leaving out for Palm Springs last week we discovered we had no chassis dash heat. Fan works, a/c works, but we have no control of temperature, it’s just on “auto” cold. There is hot coolant up front because our Webasto exchanger in the dash gets its coolant from same source as dash heat
caveat: a/c has no temperature adjustment either
we have Marathon dash heat /drivers a/c Marathon installed. We turn thermostat knob, no temperature variants.Any sugesstion:
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2 Replies
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I don’t think the dash heat/ac is the same coolant loop as the Webasto. The Webasto loop is to the heat exchangers and the dash heat goes to the heater core. Correct me if I’m wrong.
Assuming hot coolant is getting to the front, I would suspect the mixing valve is not doing it’s job. You may be able to get at it behind the front bumper up high and manually open or close. I had the same problem with my 97 Marathon and mixing valve was the culprit.
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Just to add to what Tom said, I’ve been working on my Webasto recently. I had the opposite problem, Prevost Dash heat worked, Marathon coach heat did not.
As I spent quite a bit of time up front… I know that the Prevost heat isn’t the same set of coolant lines as the Webasto heat. (at least on my 2003 XLii – we all know each bus could be different)
On our bus, the Prevost system also has a different coolant pump than the Coach Webasto heat.
Walt
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