2001 brave dash heat problem

[Goebs]

Our new to us brave arrived. We tok it for a test drive and cant get the heat from the dash to come on warm. The fan is blowing, motor is warmed up. Just wont blow hot air.
Any idea where to start to diagnose issue? It is scheduled for avservice next week for allignment, crazy loud fan belt noise, and fluids change. They will look at heat as well if I cant solve it.

Any help would be great,
Goebs

[David Kanoy]

Goebs,

I have a 2000 Adventure, I think the dash a/c & heat is set up the same as yours. On our unit there is a dash panel with 3 controls, the left is fan speed, the center a vacuum control that directs the air to the defrost vents, dash vents or floor vents and the right most control is the temperature selector.

I had a similar problem and traced it to a bad vacuum hose that goes from the middle selector switch to a vacuum motor that connects to a heater valve that controls how much hot water flows thru the heater core. On my Adventurer this vacumn motor/valve is located under the hood near the center of the rig. There is a thick black rubber shield above the radiator, loosen a few screws that hold the rubber shield in place and you should find it. The vacuum motor is silver and has an arm that connects to the water valve. The vacuum line is hard plastic and looks more like a wire than a hose. I think the line was colored green, if my memory is correct. (I'll check tomorrow and update the post.) In my case the line had rubbed against a metal support allowing air to enter and the water valve would not operate keeping the valve in the closed A/C position.

Don't know if this is your problem, but I saved myself a ton of money by finding and fixing it myself. Hope this helps, or at lease puts you in the right direction.

David Kanoy


In my case the vacuum line had

[Wizard]

Very good description David.

I might add that my control valve itself was sticking and had to be replaced. Sometimes mine would heat and not change to cool until we hit a bump in the road. Other times it was just the opposite.

The valve was fairly easy to change

[Goebs]

Thanks for the leads. I went out this eve and traced the lines. Found that there is a blue line that splits to blue and green. Followed the blue and green towards the front of the coach. The blue has been eaten in two or rubbed through. The green is un plugged and hanging. I cant see where the green one plugs in. The blue just needs a section of the line replaced.
Any idea where that green one might plug into? I am guessing it isnt this strait forward, but if so...

Thanks so much for the help guys! Much appreciated.

Goebs

[DAN L]

Quote:

Originally Posted by Goebs Thanks for the leads. I went out this eve and traced the lines. Found that there is a blue line that splits to blue and green. Followed the blue and green towards the front of the coach. The blue has been eaten in two or rubbed through. The green is un plugged and hanging. I cant see where the green one plugs in. The blue just needs a section of the line replaced. Any idea where that green one might plug into? I am guessing it isnt this strait forward, but if so... Thanks so much for the help guys! Much appreciated. Goebs

i had leaks in my vacuum lines also. i got some small rubber tubing from napa and spliced in some sections.
on my wh with 8.1 engine, both the green and blue lines go through the firewall. the blue line hooks up to a vacuum servo on the bottom ob end of the heater module. the green line hooks up to the heater water control valve inbd of the heater module hidden by the rubber air dam.

[Goebs]

Dan,
I cant find where the green line plugs into the heater anywhere. And description or pic you can point me to to find it? I am shocked that it isnt obvious but then again I am more of a parts replacer mechanic type...
Looks like something ate my blue line for lunch.Thanks again for the tips!

[dhwgulf]

I have had similar problems with my 32' Adventurer - having taken it to dealer three or four times - seems to be a flaw in design of the system.
I now have a similar problem with the air conditioning side. AC is working but is not blowing cold air in the right places

[DAN L]

Quote:

Originally Posted by Goebs Dan, I cant find where the green line plugs into the heater anywhere. And description or pic you can point me to to find it? I am shocked that it isnt obvious but then again I am more of a parts replacer mechanic type... Looks like something ate my blue line for lunch.Thanks again for the tips!

you are welcome...
the green vacuum line does not go to the heater. it goes to the vacuum operated water heater control valve installed in the 5/8'' water line inboard of the heater box. this valve is hidden from view by the rubber air dam on my moho. be careful not to tear the dam when removing screws and pulling the dam forward on the passenger side. the dam goes around the air conditioning hoses here too.
i replaced my heater control valve with a valve from schucks auto pn 74612 about a year ago. here is a picture of a similar valve from amazon.com. the vacuum line connection is on the top right side hidden from view in this picture by parts of the valve. the new valve is black plastic, the old one was metal.
small rubber vacuum hose is available that will push over the plastic line to splice it where necessary. ims i used either 1/16'' or 3/32'' hose. windshield washer hose is similar. the hose was cheap, i bought a couple of feet of each.

Amazon.com: Four Seasons 74612 Heater Valve: Automotive

[DAN L]

Quote:

Originally Posted by dhwgulf I have had similar problems with my 32' Adventurer - having taken it to dealer three or four times - seems to be a flaw in design of the system. I now have a similar problem with the air conditioning side. AC is working but is not blowing cold air in the right places

i suggest you check all the vacuum line connections on the dash mounted rotary selector valve and repair as necessary with small rubber vacuum tubing. i used either 1/16'' or 3/32'' tubing to splice in new sections. windshield washer hose is similar. a vacuum leak could be anywhere in the system and will definitely affect which vents dash air exits out of. by default, the air will exit out of the windshield defroster vents if there is no vacuum or there is a severe vacuum leak.
one of the vacuum lines going to my rotary selector was so short that raising the hinged dash panel up would pull the line off of the selector. you are correct, this is an example of bad engineering.

[dhwgulf]

OK - and THANKS!!!!!!!!!!!!!
I did not find a problem with the vac lines under the dash - but I did find a vac manifold (I think) which had no vacuum on it. I traced it to a box located inside the right front tire which had several vac connections on it. This box must be a vacuum pump?? One of the connectors was was completely off and the vac line was badly deteriorated. Replaced and reconnected. I now have air in the right places.
Still do not know about (haven't checked) the heater problem - have air but no heat, no matter what the rheostat setting (cold or hot).
Thanks again.