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Dash Heat not working '98 Allure

Yahoo Message Number: 108166
The heater hoses from the engine all the way up to the black 4 port valve located up near the dash heater core are hot. Circulation pump is working just fine. When I turn the thermostat on the dash all the way up, I get no heat - hoses to heater core are cold and stay cold.

It does not matter if I have selector switch is set to Vent, Floor, Mix or Defrost, no heat. The blower works just fine.

How often does that 4 port valve fail? How many wires go to it? How about the thermostat control? What do you think? What is your experience?

Thank you for your help, 
Tim

'98 Allure 32'
8.3 Cummins
 #30179

Re: Dash Heat not working '98 Allure

Reply #1 –
Yahoo Message Number: 108181
I have had mine fail 3 times in 3 years, but unfortunately always in the full hot position (opposite of your problem) which means no cool air from the dash. The tiny electric motor on the housing that moves the valve itself seems to be the weak point. Either that or the wiring to the little motor gets corroded or breaks.

This is the replacement valve: http://www.ebay.com/itm/RV-Motorhome-Electric-4-Hose-Heater-Control-Valve-5-pin-354-69494-SCS-034-00036-/291304231253?vxp=mtr

I am considering replacing mine with a mechanical one that has a cable on it, so the valve will absolutely move without the need for anything electrical or electronic to fail. That will mean my stock dash temp control won't work, but that's a small price to pay for having a working dash heater - and air conditioner!

Mark M

1998 Intrigue #10661

Re: Dash Heat not working '98 Allure

Reply #2 –
Yahoo Message Number: 108189
Tim:

More than likely the 4 port valve is bad.

Kevin Waite (Former Country Coach Service Tech. & Owner) K&M Mobile RV Repair LLC
95430 Noraton Rd.

Junction City, OR. 97448
541-953-6162 (Cell)

kvn.wt.7629@...

Re: Dash Heat not working '98 Allure

Reply #3 –
Yahoo Message Number: 108195
Thanks Mark,

You have confirmed my suspicion about the valve being a weak point. I like the way you think regarding replacing it with a mechanical valve and cable. I prefer reliability and certainty over convenience. But then it is not convenient to have that "convenient" electric valve fail in the hot position. Thanks for the Ebay link. Also on Ebay are 4-port heater valves with vacuum motors. New 74809 Heater Control Valve 4 Port Vaccum Operated

image

New 74809 Heater Control Valve 4 Port Vaccum Oper... US $14.99 New other (see details) in eBay Motors, Parts & Accessories, Car & Truck Parts

View on www.ebay.com

right

If the electric motor is the weak point then this may solve that problem. Instead of a cable like you were suggesting, I was thinking of a "hose and straw" and a little clamp. Need heat, suck on the straw, clamp off the hose. Sounds simple, might work. Seriously, there is a vacuum source under the dash, we could tap into that and control it with a vacuum switching valve.

Tim

Re: Dash Heat not working '98 Allure

Reply #4 –
Yahoo Message Number: 108225
That sounds good, unless the vacuum motor fails....

Let me know what you end up doing, I would be curious.

Thanks,
Mark M
 

Re: Dash Heat not working '98 Allure

Reply #5 –
Yahoo Message Number: 108309
Don't know what coach you are dealing with, but some of these things had a wireless thermostat on that operated the mixing valve.I know for a fact these were on 2003/2004 models .I ran into this on a Coachman that I was working on. When these things went, they would open the hot water ports so your defroster would work.