Saturday, May 29, 2021

Inspecting the ATS

One of the items that has been  a common problem in the FUSE is the Automatic Transfer Switch (ATS) failing.  The ATS is the device that selects if the generator or the shore power plug is what is powering the FUSE 110v loads.   I wrote earlier about the ATS at:  The one in our fuse is a 41300 and info can be found at:

ATS With cover on

Big problem is when the ATS fails you get 0 power from either.  Oh, and and an acrid smell comes out (and possibly a small amount of smoke). For me it happened just outside of Dallas, Texas and caused us to cut our trip a couple of days short.   BTW - your 12volt system will still work if this happens, just no recharging the batteries from the shore power or generator so the lights stilled work.

So how can you avoid this.  Well a good practice is to inspect the ATS once (or twice) a year.  What you are going to need is a flashlight, a small screwdriver and a 5/32" hex key/driver - Now let's go over the steps.  

The ATS is located in the electrical box with the shore power cord.  It is a pretty tight fit in there.

Important Note:  Make sure the shore power is unplugged and the generator is off.  This is electrical and you can get hurt if the power is on.

First step is to take the cover off of the ATS.  It unsnaps from the top of the cover.  There are some keys at the bottom of the unit.  Be gentle, but it comes off pretty easy.

ATS Cover Off

Once open, you need to take a look at the wires.  If any of the wires looks burned, the wire insulation looks bubbled, there is any heat damage you have failed the inspection.  Get this fixed now.  If everything looks ok, then continue on.

ATS with Cover off

The next thing you need to check is if the connections are tight.  On the ATS you will see several electrical relays with hex screws.  There are 8 of these connections.  Check to make sure these are tight.  Don't over tighten.  If they are already tight, you are good.  If they are loose tighten them down to 30 in-lbs.  This is listed on the cover so refer to what it says if there is a change between model revisions.  

FUSE ATS annotated


How much is 30 in-lbs? What does that mean? Tighten, but do not crank it down.  Don't use any leverage from your wrist.  You will put that much force on the connector just by using your hand without any leverage.

T handle Hex key

I purchased a T-handle hex key just to do this with.  This was a tip that was pointed out at the last Fuse Rally.  It makes this job much easier than with traditional L shaped wrenches.

Also check the screws on the terminals on the top of the ATS.  On mine this required a small screwdriver.  If everything is tight then great, otherwise, tighten them down but again, do not over tighten.

At this point you are done.  Put the cover back on and you are good to go.  If you need repairs, take care of them.    

This is a good thing to inspect regularly. It only takes 5-10 min and can save you from trouble down the road.  At the Spring 2021 Fuse rally, Bob Garbe went around and inspected them for folks (13 if I recall correctly) and it was greatly appreciated by all. 


  1. Well I didn't get to the rally and still have this on my to do list. Thanks for the details!

  2. Don, did you notice if the end of the wires were tinned or bare? My suspicion, formed after 20 minutes of research, has been that the shore power cable has tinned leads and they should NOT be.

    As always thanks for the thorough and well written post. Steve