Dash A/C Fan Only Works on High in 2004 Sightseer 30B

[wschneid]

I have a 2004 Winnebago Sightseer 30B that I recently purchased. I noticed that the fan for the dash AC only worked on high speed. I heard that is probably a resister, but how do you access the controls inside the dash?

wschneid

 

[Morich]

Not looked a one in a while on an RV, so consider this as "general" things to look for more than giving any specific spot for the chassis your RV is built on?
I think you can get this one done without going too far into the controls or under the dash in many cases! YEAH!
There is a resister pack at some point in the airflow. That small pack has a set of wire coils which make varios resistance, depending on which setting the control is on. Those wire coils change how much resistance the blower circuit has as the switch is changed. They also tend to get hot and are placed in the airflow to cool them but they do tend to burn out with age.
So when looking under the dash and depending on different chassis it may be out under the hood, but expect to see a big bulky cover over the space where the heat and cooling is done.
This is where things can be build different and I see the parts drawings for your RV show the pack as being outside under the hood where the heater and air coils, etc. stick through the firewall! I have normally found the pack inside near where the back of the blower motor sticks out??
So it may take a bit of looking, depending what your chassis did. Can you see up under a flap often set in to conceal the motor, etc. that is almost directly over where the passenger feet go? I have found the pack inside but your drawing shows outside??

Idea is to spot andelctrical plug for 4-5 wires that plug onto the part of the pack that extends out of the cover. Not too many sets of wires on that part of the RV but just maybe less than 2X2?
I think of it as inside and near the motor but not looking at yurRV, so keep an open mind! Maybe worth making sure it is pluggged good but theser are kind of common to burn one or mor of the coils and maybe two screws to hold it in, making it not too hard to changed? But that is also depending on how they built it!!!
Common auto parts store item for better price/availability than RV supply!
This is a common one for Ford:

 

[wschneid]

Not looked a one in a while on an RV, so consider this as "general" things to look for more than giving any specific spot for the chassis your RV is built on?
I think you can get this one done without going too far into the controls or under the dash in many cases! YEAH!
There is a resister pack at some point in the airflow. That small pack has a set of wire coils which make varios resistance, depending on which setting the control is on. Those wire coils change how much resistance the blower circuit has as the switch is changed. They also tend to get hot and are placed in the airflow to cool them but they do tend to burn out with age.
So when looking under the dash and depending on different chassis it may be out under the hood, but expect to see a big bulky cover over the space where the heat and cooling is done.
This is where things can be build different and I see the parts drawings for your RV show the pack as being outside under the hood where the heater and air coils, etc. stick through the firewall! I have normally found the pack inside near where the back of the blower motor sticks out??
So it may take a bit of looking, depending what your chassis did. Can you see up under a flap often set in to conceal the motor, etc. that is almost directly over where the passenger feet go? I have found the pack inside but your drawing shows outside??
View attachment 2489414

Idea is to spot andelctrical plug for 4-5 wires that plug onto the part of the pack that extends out of the cover. Not too many sets of wires on that part of the RV but just maybe less than 2X2?
I think of it as inside and near the motor but not looking at yurRV, so keep an open mind! Maybe worth making sure it is pluggged good but theser are kind of common to burn one or mor of the coils and maybe two screws to hold it in, making it not too hard to changed? But that is also depending on how they built it!!!
Common auto parts store item for better price/availability than RV supply!
This is a common one for Ford:

View attachment 2489417

Thanks for the info. I have a Ford chassis with the Triton V-10 310hp engine. If that makes any difference.

 

[Morich]

Good enough! That makes the odds of the drawing mor elikely to be correct. But it is always a game of playing the odds on whether it is the resister pack! Always "possible" to be some wire broken or other things but this is so common, it is one I look at first as the wires do get broken when Ive had what you describe. The coils of wire are added togehter to get more and more resitance in the power going to the moter and that is done by the switch but if some of these wires, etc. on the pack go open, the fan runs at full speed or none!
My trouble with these has never been on an RV but cars and it was usually pretty easy to get in under the dash and it was kind of sticking right out.
RV do have more trouble with things getting hard to reach, so I'll wish you luck and see how that works out?

 

[MikeyC-WO]

Thanks for the info. I have a Ford chassis with the Triton V-10 310hp engine. If that makes any difference.

I have the f53 v10 also had similar issue the resistor pack on mine probably yours is near the blower motor under the passenger foot well. I was able to solve the issue even though it’s tight. Look there before engine compartment.

 

[SMH2026]

HI,
I just ordered the same part for my '05 Sightseer 29R. The resistor pack on my unit is accessible by raising the engine hood, look to the left where the HVAC unit lives. The unit has a 4 wire plug and is secured in place by 2 small philips head screws. The small bullet shaped device near the resister coils is a thermal fuse. When that fuse fails you get only high speed blowers. Strangely AutoZone had the part under the Duralast brand, part number JA1501, it's ~ $33. Since you have the blower operational on high the blower motor and all associated wiring is probably good. Take the unit you have to match it up.

Good Luck.

 

[RayIN]

Often a corroded connections can cause this problem. A spray can of plastic-safe contact cleaner is your friend.

 

[wschneid]

HI,
I just ordered the same part for my '05 Sightseer 29R. The resistor pack on my unit is accessible by raising the engine hood, look to the left where the HVAC unit lives. The unit has a 4 wire plug and is secured in place by 2 small philips head screws. The small bullet shaped device near the resister coils is a thermal fuse. When that fuse fails you get only high speed blowers. Strangely AutoZone had the part under the Duralast brand, part number JA1501, it's ~ $33. Since you have the blower operational on high the blower motor and all associated wiring is probably good. Take the unit you have to match it up.

Good Luck.

I just replaced the Resistor part, but It did not help. Do you have a picture of the thermal fuse? I can't seem to locate it.

Bill Schneider

 

[wschneid]

Often a corroded connections can cause this problem. A spray can of plastic-safe contact cleaner is your friend.

I think you were right. I replaced the resistor and it still did not work properly. I took the old part, cleaned it, made sure the plug was securely fitted in and reinstalled it. Now it works like it should. Thanks for the info.

 

[wschneid]

Not looked a one in a while on an RV, so consider this as "general" things to look for more than giving any specific spot for the chassis your RV is built on?
I think you can get this one done without going too far into the controls or under the dash in many cases! YEAH!
There is a resister pack at some point in the airflow. That small pack has a set of wire coils which make varios resistance, depending on which setting the control is on. Those wire coils change how much resistance the blower circuit has as the switch is changed. They also tend to get hot and are placed in the airflow to cool them but they do tend to burn out with age.
So when looking under the dash and depending on different chassis it may be out under the hood, but expect to see a big bulky cover over the space where the heat and cooling is done.
This is where things can be build different and I see the parts drawings for your RV show the pack as being outside under the hood where the heater and air coils, etc. stick through the firewall! I have normally found the pack inside near where the back of the blower motor sticks out??
So it may take a bit of looking, depending what your chassis did. Can you see up under a flap often set in to conceal the motor, etc. that is almost directly over where the passenger feet go? I have found the pack inside but your drawing shows outside??
View attachment 2489414

Idea is to spot andelctrical plug for 4-5 wires that plug onto the part of the pack that extends out of the cover. Not too many sets of wires on that part of the RV but just maybe less than 2X2?
I think of it as inside and near the motor but not looking at yurRV, so keep an open mind! Maybe worth making sure it is pluggged good but theser are kind of common to burn one or mor of the coils and maybe two screws to hold it in, making it not too hard to changed? But that is also depending on how they built it!!!
Common auto parts store item for better price/availability than RV supply!
This is a common one for Ford:

View attachment 2489417

Thanks for the info.

 

[wschneid]

HI,
I just ordered the same part for my '05 Sightseer 29R. The resistor pack on my unit is accessible by raising the engine hood, look to the left where the HVAC unit lives. The unit has a 4 wire plug and is secured in place by 2 small philips head screws. The small bullet shaped device near the resister coils is a thermal fuse. When that fuse fails you get only high speed blowers. Strangely AutoZone had the part under the Duralast brand, part number JA1501, it's ~ $33. Since you have the blower operational on high the blower motor and all associated wiring is probably good. Take the unit you have to match it up.

Good Luck.

I got it working. Thanks for the help.

 

[Morich]

I have never gotten as far as needing to ID the parts, so the thermal fuse is a bit of guess. But I have heard/read about it and always assumed it is the small part that might look like a "rocket" if we use our imagination?Take a look at the pack in post 2 above if wanting to know where I "think" we find that thermal fuse?
But I can't imagine ever trying to change just that fuse on the board, so I've never questioned it further.
But it is true that I find many more small parts failing on RV than the large ones, so we do need to keep in mind how much more corrosion we can get on RV, compared to things we drive every few days.
It's just part of the RV experience to know that things that we DON'T use go down hill faster than those we use every few days.
Like the muscles in our brain? If we don't use them we lose them!

 

[wschneid]

Thanks for your reply, but I got it fixed. I cleaned the contacts and reseated the plug and it worked fine after that.

Bill Schneider

 

[Morich]

A1 grade on looking closer before just changing a part! That is part of what I find lacking in way too many cases when I watch repairs being done. Rv are especially prone to corrosion, partly due to them being stored longer and that lets corrosion get thicker to shut down the power.
So what I have seen is repair just going straight to changing out an expensive part and things then work! But when my brother and I got into testing some of those parts that went in the trash, there were a number of them which still worked when we plugged them into power!
DUH! The only explanation we could come up with was that the plug and contacts were corroded until we plugged and replugged them!
Just think of how many control boards get changed out and things work again?
If we are doing the work for ourself, we need to check a little closer than the "pros" since it IS our time and money being wasted!

 

[SMH2026]

I just replaced the Resistor part, but It did not help. Do you have a picture of the thermal fuse? I can't seem to locate it.

Bill Schneider

Hi,
The thermal fuse is the silver bullet shaped unit on the resistor pack itself. If you can solder wires you can replace the thermal fuse. The DIGIKEY part number is 3171136ND. Cost is unit one: $0.87 so if the nichrome wire coils are not broken you have a good chance of repairing the unit by replacing the thermal fuse.

Here's a picture. When you replace it take pictures and match the orientation and position on the mounting. Doing this will maintain the protection of the design. When soldering the fuse into place use a needle nose plier as a heat sink so you done't heat the fuse. Make sure the wire resistor elements coils are evenly spaced to assure good airflow.

Good Luck,

SMH

 

[Morich]

Never had a reason to wonder before or have time to ask but today is the day for me to learn a bit about this little gizmo. I knew what it did but not why, so wondered why it seemed to be "polarity sensitive"?
AI gives me an answer which seems to make sense as they do not describe it as "polarity sensitive" in the electrical sense but it is sensitve to being placed in the correct direction for mechanical purposes! There is a spring and pellet inside that makes the location of the pellet critical to it opperating at the correct temperature!
And that brings a whole different line of thought about what we might do to repair if this item goes bad due to higher than rated temperature?
I've never gone that low on the repair bill but if it is rated for what looks like 120 degrees to me, can I actually expect to get away with soldering the wires on each side? Or does heating solder to flow going to overheat the new item we are installing? I'm thinking I will be better served to bite the bullet for the whole $30 part rather than the $1 part that I am prone to ruining and having to change a second time!
I have found it very easy to think I can do things that get me into more and more trouble!

 

[SMH2026]

The thermal fuse is not polarity sensitive. If you get a unit from digikey spring for 2, that way you'll have a spare (cheap insurance at 87 cents). The act of soldering can cause the fuse to melt, that's why I use medical forceps or needle nose pliers as the heatsink (blocker) during soldering. Couple of things to do to assure success: cut the old / dead piece as close to the body of the device as possible. Use the leads that are left on the assembly as the basis to install the new fuse. Cut the new fuse leads to largely match up with the leads still installed. Clip one side of the new fuse with the forceps to the old lead. The forceps MUST be between the heat source and the fuse body. Use 60/40 solder and "quickly" solder the leads together. 60/40 lead.tin is not low lead but it's much easier to solder with. Be patient, let the connection cool, take your time. When cool clip the other new lead and solder it to the old lead, again do it quickly so as to minimize possibility of overheating. You want the fuse body to be in the same spot as the old. That will assure it works properly. Good Luck.

 

[SMH2026]

BTW: The thermal fuse protects the coach and HVAC system , If the fan fails the airflow stops. Those wire coils are made of nichrome and they will get REAL hot, probably glow like a toaster element. The fuse is directly above the resistors when the pack is installed, heat rises, the fuse opens. The unit you're replacing is 25 years old or more and vibration, thermal cycling will cause a failure even there is nothing wrong with the blower. It in effect wears out or ages out.