Community Forums

4wheelcrusin · 10-31-2019, 10:20 PM

I have a 2003 National Islander, diesel pusher. Dash AC only blows cool on the driver side, hot on the passenger side. Does anyone have any idea what the problem is?

Dav L · 10-31-2019, 11:10 PM

there might be a blend air door that is stuck. It's possible that there are two, one for driver, one for passenger for independent settings.
To determine which side is stuck...can you get either side to switch from cooling to heat and back to cooling?
You can try changing modes and listening for air doors to move.
If both sides were stuck hot, then I would have guessed the hot water valve is stuck on.
If neither side got cold, then I would have you check if the AC compressor is spinning when cold is set.

4wheelcrusin · 10-31-2019, 11:44 PM

Thanks! I’ll check the blend doors. There is separate setting controls . I already know the passenger side setting control does nothing. I’ll check the driver side and let you know.

"007" · 11-01-2019, 05:25 PM

If you have a EVAN's AC Unit may have some plastic air lines loose or dried out, Evans info can be found in this link.

nathaniel · 11-01-2019, 05:54 PM

Also check you hot water control valve. If its stuck in the open position the AC will not overcome the heat in the heater coil. I had this happen to me. I had to put in a manual ball valve to confirm that was the issue and then replaced the 12volt valve.

4wheelcrusin · 11-01-2019, 06:03 PM

DavL

I checked the blend doors and there working. Don't understand why I only get hot air from the top (actually the middle) of the box and cold from the bottom. Any other ideas? I'm at the stage were I'm going to pull the whole dash apart so I can get to the blower box. It's real tight under there! One thing I did notice is there's extra air supply ports that are capped off. There's 2 on the left side and 2 on the very top that are capped off. Someone else has definitely worked on this because the flex tubes are held in place with sheet metal screws. The vacuum pump is working and when I manually move the blend doors there's really no difference. Do you know if there's suppose to be a heater core shut-off valve? If so it doesn't have one. Thanks for your help.

4wheelcrusin · 11-01-2019, 06:10 PM

I looked today for the control valve, but I couldn't find one in the heater core water line anywhere. I did notice something I thought was strange. There's 2 heater core water hoses, but one of them has a "Y" tube in it and splits off to somewhere else. Any ideas what that might be?

nathaniel · 11-01-2019, 06:24 PM

One is the supply the other is the return.i dont know what the y in the line feeds. Do you have a heat coil in the living area for heat when traveling? You could test your theory of the heating control valve by putting a ball valve in line on the single line. As long as your cutting of the flow for hot water it will remove that issue from the equation. Then you can see if your getting the cold blast from AC I wouldn't pull the dash apart just yet

4wheelcrusin · 11-01-2019, 06:34 PM

I'll have to pick up a valve to try that theory. I know you're saying not to take the dash apart just yet, but there's no windshield defroster air either. I think someone just did a quick
and sloppy repair (if you want to call it that).

Dav L · 11-01-2019, 09:44 PM

Quote:

Originally Posted by 4wheelcrusin

I'll have to pick up a valve to try that theory. I know you're saying not to take the dash apart just yet, but there's no windshield defroster air either. I think someone just did a quick
and sloppy repair (if you want to call it that).

You can also just squash the heater hose with a some wood inbetween a pair of vise grips to prove the hot water valve theory.

nathaniel · 11-02-2019, 06:05 AM

Quote:

Originally Posted by Dav L

You can also just squash the heater hose with a some wood inbetween a pair of vise grips to prove the hot water valve theory.

Good idea, I left the ball valve in place when I did it to mine. Just in case of the temp control valve failure if I'm on the road I can stop and simply cut off the flow and back on the road with ac...

To the OP, with the damper control, when you have the ignition in the on position and select different positions for air flow. Do you hear the damper change or hear anything trying to move? When you put it in max AC can you hear anything like the outside air damper close?.

4wheelcrusin · 11-03-2019, 05:41 AM

Damper doors are working after visual inspection. I pulled the electrical plugs off of the valves. After inspecting I found that the driver side stays closed and the passenger side stays open. I tested the plug wires and there’s only power going to one terminal for the driver side and it’s pulsating. No power to any terminals on the passenger side. This system is set up like climate control for the driver and passenger.

4wheelcrusin · 11-03-2019, 10:59 AM

Ok guys, finally got pics of where the valves are located and what they look like. Any comments are greatly appreciated.

Dav L · 11-03-2019, 02:44 PM

I guess you could electrically swap the valves to isolate whether the valve is bad or the wiring / control system.

Do you have an electrical schematic of the RV? That's the most important thing to get once you start trying to diagnose stuff like this.