Any ideas?

[Saltynuts]

Hi People.
I am looking for some help. I have a ff 189fds with a dometic fridge. I have used the trailer a few times and I noticed that the 2 fans at the back of the fridge never run. How do They work? What are they for? Thanks in advance Salty.

[webslave]

Most of the Dometic refrigerators do not come with fans. Fans found in these RV refrigerators are usually after-market add-ons in order to "boost" the refrigerator's ability to cool; that ability being borderline in really hot conditions. They are sometimes dealer or manufacturer installed, but, most commonly user installed.

It may be that a previous owner put them in and determined that they were either too noisy or not of any great benefit when compared to the power they consume, particularly if the previous owner "boondocked" and power consumption was an issue.

They are simple 12 volt fans with no thermostats, so, in trouble shooting, I would look for their 12 volt inputs and see if a) the inputs are connected or b) if the inputs are "hot" if they are connected.

[TCP]

My 2010 came with a single fan back there. It is there to move air over the upper condenser coils because, with the slide, the upper vent is not above the coils, but beside them(not top vented like non-slide fridge). I replaced the single unit with a couple of lower current fans as the single seemed to run very quite loudly.

If you pull the lower outside panel on the fridge, you will see a wire with an inline fuse going up towards the top. this is the power for the fan.

If you pull the upper outside panel on the fridge you will see the fan(s) and if you follow the wire from them, you will see it goes through a thermo-switch mounted on the upper condenser coils on the far right side. This switch controls when the fan turns on/off. Mine seems to run anytime it is over 22-25C outside (75F or so) and the fridge is on. I would check the fuse and if it is ok, hold a lighter or heat gun under the thermo-switch to confirm that the fan comes on with enough heat.

Originally Posted by Saltynuts

Hi People.
I am looking for some help. I have a ff 189fds with a dometic fridge. I have used the trailer a few times and I noticed that the 2 fans at the back of the fridge never run. How do They work? What are they for? Thanks in advance Salty.

[webslave]

That is true for the units with the reefer in a slide, however, that fan installation is required due to the installation location of the reefer and its corresponding vent site.

The 189s do not have their reefer in a slide and would not come with the Dometic optional location fan, let alone two fans.

This is a typical add-on fan application:



One of the problems with this type of application is finding power. Prior to '07 or '08, the Dometic refrigerators had hot wires at the bulb and door switch for the bulb, that were "hot" all the time and the circuit was completed to ground by the switch. It was possible to wire to that hot wire and the fan would run (all the time - no thermostat). Dometic then changed their wiring system on many of their models, such that the switch did not complete a ground path, but, I suspect, operated a relay by completing a ground path, resulting in their being no "hot" wire readily available inside the cabinet for these add-on fans. It is possible that the fans were installed with the idea of tapping into the light (as in the photo above), only to find that there wasn't a hot wire to use. It may also be possible the fans are just plain dead (they aren't high-end fans), the hot wire connection or the fan's ground wire connection may be bad, or, the fans were installed only to find that there wasn't a hot wire readily available and the intent was to "wait until another day" to figure out how to supply power and that "day" never came (if they were installed by a previous owner).

[TCP]

He has a 189FDS which HAS the slide, with a fridge and the fan in the outside compartment. I also have a 189FDS and it HAS the fridge in the slide. Maybe he also has the fans inside, they certainly aren't stock, whereas the outside ones are. There is an actual thermoswitch in the upper condenser, trust me.

http://www.cruiserrv.com/fun-finder-...fications.html

They look something like this:

http://t3.gstatic.com/images?q=tbn:A...GV25TBddlQ&t=1

Originally Posted by webslave

That is true for the units with the reefer in a slide, however, that fan installation is required due to the installation location of the reefer and its corresponding vent site.

The 189s do not have their reefer in a slide and would not come with the Dometic optional location fan, let alone two fans.

This is a typical add-on fan application:



One of the problems with this type of application is finding power. Prior to '07 or '08, the Dometic refrigerators had hot wires at the bulb and door switch for the bulb, that were "hot" all the time and the circuit was completed to ground by the switch. It was possible to wire to that hot wire and the fan would run (all the time - no thermostat). Dometic then changed their wiring system on many of their models, such that the switch did not complete a ground path, but, I suspect, operated a relay by completing a ground path, resulting in their being no "hot" wire readily available inside the cabinet for these add-on fans. It is possible that the fans were installed with the idea of tapping into the light (as in the photo above), only to find that there wasn't a hot wire to use. It may also be possible the fans are just plain dead (they aren't high-end fans), the hot wire connection or the fan's ground wire connection may be bad, or, the fans were installed only to find that there wasn't a hot wire readily available and the intent was to "wait until another day" to figure out how to supply power and that "day" never came (if they were installed by a previous owner).

[webslave]

See that's what happens when you get old!

I didn't have my glasses on (tri-focals now...) and read 189fBs not the fDs. Haven't worked on nor looked at an fDs. Interesting layout.

With the reefer in the slide, then TCP is most certainly correct...that is the "alternate" installation that would need the Dometic fan assembly to compensate for the poorer draft with no roof top vent.

Disregard the afore mentioned rambling of an old fart...

[TCP]

my wife calls me "grumpy" way too much.

Funny thing about the original fan. It had a a rating of 480milliamps, which is very high for a 4" fan. I replaced it with two of the same size that each had a 85milliamp draw. The two of them together was a total of 170mA. Not really a battery power issue with them like that, but the original was really noisy as well.

Originally Posted by webslave

See that's what happens when you get old!

I didn't have my glasses on (tri-focals now...) and read 189fBs not the fDs. Haven't worked on nor looked at an fDs. Interesting layout.

With the reefer in the slide, then TCP is most certainly correct...that is the "alternate" installation that would need the Dometic fan assembly to compensate for the poorer draft with no roof top vent.

Disregard the afore mentioned rambling of an old fart...

[Saltynuts]

Thanks for the ideas you guys. when I get my next day off I will check out the fans. Thanks again Salty