Under coach light

[Amg]

I have a 2016 Interstate. I never really knew it had an under coach light. I noticed a light shining underneath and then looked at my manual to see where the switch was. I found the switch on the side of the front passenger seat. However, the switch is not working for the light. The switch for the awning does work.

Has anyone else had this problem and the solution. Does anyone know where the fuse is located they are poorly marked. Or another way of turning off the light. Thanks

[J&J In A Can]

Interesting problem. While the manual was kind enough to mention where the switches are, it was not kind enough to mention that they each have a battery inside. The switch is actually like a wireless remote. If you pop what appears to be the entire switch off, perhaps with a finger nail, you will see the battery inside the part that comes off. Get a new battery and all will be well again, for a while.

[Amg]

Really appreciate the help. The manual really should have said there was a battery. Do you know type of battery so I can buy one in advance.

[J&J In A Can]

It is a large size button cell. Sorry I can't remember the number stamped on it. As soon as you pop the cover off, you can see the number. Two seconds tops.

[J&J In A Can]

I just went out to check. I used DL2032 Duracell.

[Amg]

Thanks

Purchased the batteries and changed both the awning and coach light batteries. When I push the bottom for the coach light it does show working by a blue light coming on when pushed. However, does not turn off light. The light is not bright and seems to shine from the front and back of the coach. Don’t know if a short or something else.

Is there another solution? Does anybody know If I can pull a fuse to shut it off and which fuse it is. The fuses are not marked very well. Thanks again.

[J&J In A Can]

If you have some warranty left, like I do, this would be a good time to get it in and let Airstream deal with it. IMO. Otherwise, get into the schematics in the back of the manual and track down the circuit to find the fuse. Also, if you try the battery disconnect switch and the lights stay on, the fuse may be located under the driver seat. If they go out, the fuse is probably in the back on the street side. Either way you will probably need to find it on the schematic. Be careful with the fuses under the driver seat. Some of them are used by Mercedes to do things that can really screw up you rig if they are not correct.

[Amg]

Thanks

I called Airstream. They got back and said it may be an RF modulator. They said it is located under the front wheel well. Also said it has to be programmed. Thus I am forced to trail to an Airstream dealer. I bought the unit from North Trail in South Florida. They closed their Ft. Lauderdale location where I live and now only have the Naples location about a three hour drive.

I asked them about removing a fuse but they said that is not an option since the fuse has a lot more then just the under carriage light on it.

Also unfortunately my unit is three months past warranty.

A minor issue is turning out to be a major pain in the rear.

[Titus]

From what I can glean: Apparently the light is powered from somewhere by 12V. But instead of running the 12V through a switch, they have used a wireless remote switch to control the light. I assume the 'rf modulator' is part of the communication between the switch and the light? I would look on-line to see if I can find a replacement switch sender unit and 'receiver' unit on the light. I'll bet you can replace it yourself much cheaper than paying for the dealer service - and save a three hour drive.

[Titus]

Here is an example of what I had in mind. Not sure how the switch can be self-powered, but great if it somehow works.

https://www.amazon.com/12V-Controlle...ch+with+remote

Here is another example that mentions the 'rf' that Airstream refers too. The programming that Airstream referenced is apparently like you do to synchronize your remote to your garage door opener.

https://www.amazon.com/eMylo-Wireles...ch+with+remote

[Alex AVI]

AMG, TITUS - I had no idea the undercoach light in the 2016 is RF controlled. If it was still under warranty, I would obviously want it repaired to the same original config, even if it means replacing the RF modulator. But does the undercoach light really need to be wirelessly controlled? Since it is no longer under warranty, why not just wire a switch & relay from your dash to the light? There are many switch blanks available to put a switch right next to driver.

[Amg]

Thanks everybody for help.

Airstream charges $85 for the RF modulator. The real problem is they “think” that may be the problem. What I probably willl do is get a good local RV repair shop with electrical experience to look at problem and repair and/ replace. It is unfortunate that there are no diagrams available for the system. I agree replacing it or getting rid of it is probably better. Problem right now it is always on and draining my battery when not plugged in

[Titus]

Alex
I was actually kinda intrigued by the idea of having a wireless switch, so that I didn't have to pull wires to feed the switch and to pull them from the desired location of the switch to the light. But... to each his own.

[Pahaska]

I do not miss having those lights on my 2014. I would arm myself with a diagonal pliers and simply clip the wires to the offending under chassis lamps. Cost = $0.00.

[Alex AVI]

Originally Posted by Amg

Thanks everybody for help.

Airstream charges $85 for the RF modulator. The real problem is they “think” that may be the problem. What I probably willl do is get a good local RV repair shop with electrical experience to look at problem and repair and/ replace. It is unfortunate that there are no diagrams available for the system. I agree replacing it or getting rid of it is probably better. Problem right now it is always on and draining my battery when not plugged in

AMG - See attached pics below. Under coach lights (along with all your other house lights) are on Ckt 2, Yellow(2) & White(150) wires. The RF Modulator is just a dimmer. There is no reason for it to not work if bypassed and switched mechanically straight to 12v. Of course you would lose dmiming capability. When we use under coach lighting, it is either on/off (not dimmed) so losing dimming is not issue for me.If you just want it to not drain your batts (until you decide to fix or not fix), just clip the power connection from the RF Modulator to the Ckt 2. Make sure you turn off power before doing so and make sure clipped wires are capped after you clip them.

Update - Oops, sorry diagrams are sideways. Now fixed

[Alex AVI]

Originally Posted by Titus

Alex
I was actually kinda intrigued by the idea of having a wireless switch, so that I didn't have to pull wires to feed the switch and to pull them from the desired location of the switch to the light. But... to each his own.

TITUS - Ok, true (though still just a gimmick for a light) I would not mind it if not for the expense AMG is facing based on AS quote of $85 + whatever labor they charge. I only gave my suggestion to help AMG save the expensive price of having it fixed outside of warranty. The price they want is just too outrageous. If this was mine and knowing I would only buy the part and do the repair myself, I most likely would still not buy the replacement RF Modulator. If AMG is handy enough to bypass the RF Modulator, it would only cost him the price of a mechanical switch, wire (and maybe a relay if he wants that route).

PS - another option is to connect on the same RF Modulator that controls/dims the awning lights since that still works (see diagrams I posted).

[Amg]

Thanks everybody for your help. Unfortunately, I am totally not mechanical. I think the best option for me is to get a local RV mechanic, show him your diagram and direct wire the light. May do the same with the awning light to avoid a future problem. Thanks again

[Titus]

Are the under coach lights just for aesthetics or do they serve a useful purpose? Only time I can think of wanting better outside lighting is when dumping the tanks. I carry a headlight that looks goofy but works well.

[Alex AVI]

Originally Posted by Titus

Are the under coach lights just for aesthetics or do they serve a useful purpose? Only time I can think of wanting better outside lighting is when dumping the tanks. I carry a headlight that looks goofy but works well.

TITUS - I assumed the under coach lights are on all MY. It is patio lighting but unfortunately only on C/S. . I was actually thinking doing the R/S too. I have my own name for this - I call it A51UFO-Leds Discourages small nocturnals/animals from sleeping under AI.

[swilly43]

Do any of thems still work? After replacing the RF modulator twice and the LED strand twice, I gave up. Never used it except to show off. Wasted amps in my opinion.