Dash temperature problem

[NaramataSlim]

This is my first post . I was driving down I-5 near Stockton Ca on a very bumpy part when my AC suddenly went warm. I moved the temperature controller but it stays constant no changes.I have looked for the heater valve but i cannot locate it. i have a 32 ft 2004 Fleetwood Terra with a ford chassis. I hope someone can direct me where to look or have idea what might be wrong.

[Muddypaws]

Yup, the roads around Stockton are pretty bad. Sounds lke a vacuum line may have fallen off or broken.

Ford tends to not use heater valves. The heater core is always hot. The airflow over the heater core is controlled pneumatically if it's anything like the F series chassis.

On my 2001 F250 (7.3 PSD) and my sons 2003 F350 (V10) I added a vacuum actuated water valve (from an older model Ford Ranger) to shut off the flow of hot water to the heater core because the A/C did not work well at all. The vacuum block on both of those trucks was on the passenger side firewall inside the cab. Yours may be similar.

Good luck with it!
Muddypaws

[bluepill]

To isolate the problem (i.e. is it the heater adding heat or the a/c failing to cool), I clamp off one of the heater hoses to stop the flow of hot coolant to the heater core. I prefer a vise-grip needle nose plier, but a small c-clamp can work also.

If this "cures" the problem, follow normal trouble shooting for the heater by checking actuators, valves, etc.

If not, you will have to focus on the A/C side of the system. My first test would be a static (not running) check of low side pressure to see if you have lost refergerant.

[Winnebeater]

agree with Muddypaws on the vacuum line theory. I have an older motorhome and I had the reverse issue were mine was always cold. It turned out to be two loose vacuum lines. I reconnected them and it's worked flawlessly sense. The two lines on mine came loose from behind the dash controls, but I have older GM chassis so the source of my issue may be different than yours.

I found that I had a leak in the vacuum controls by hooking a vacuum pump to the system and trying to draw a vacuum on it. I could not develop a vacuum with the vacuum pump, so I started looking. My N-laws motorhome had the same issue.

[dsbike]

I have a 2004 Coachman with the Ford Chassis. I have a cable operated heater control valve. When I first got my MH the cable clamp was adjusted incorrectly & I had the same problem as you. My heater control valve is located in the engine compartment on the heater hose.

[NaramataSlim]

Thanks for all the suggestions. I found the problem and a cable had fallen off a valve in the Fan area . Had a little problem finding out how to remove cover in front of the passenger seat . Now i need to find a locking cap so it will not fall off again.

[Dunner]

Try HD or Lowe's for the cap.