Help. Can't get blind spot to work when cargo box attached.

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

GeorgeGG

Member
Joined
Mar 9, 2021
Posts
13
Reaction score
0
Location
Boston
Hi guys,

I got a Hitch Mounted Cargo Box (https://www.stowaway2.com/hitch-cargo-boxes) for my 2020 Expedition Max. The box connects to the 4-pin trailer wiring connector (for the tail lights and the license plate light).

Now the problem is, when I connect the 4-pin trailer plug, the Expy says "Blind spot & cross traffic alert deact. Trailer attached".

I'd really like to get at least BLIS working. I can live without the cross traffic alert, but we are about to go on an about 26-hour drive, switching drivers, and the wife swears by the BLIS system.

Here is what I am doing. Starting with all trailers deleted, ignition off and cargo box electrical cable connected to the hitch electrical connector.


1) Turn on the ignition. The console says "Blind spot & cross traffic alert deact. Trailer attached".

View media item 7473

2) I OK out of it. Select "Towing", then "Trailer Setup". It says "Press OK for trailer options".

View media item 7474

3) I select OK, then "Add Trailer".

View media item 7475

4) It asks me to name the trailer. I name it "a".

5) It asks if I want to "Add Trailer Blind Spot" and I say "Yes"

View media item 7476
6) It asks "Is the width less then 9ft and length less then 33ft?". I say "Yes".

7) It says "Enter Trailer Length". I leave it at the default 18 ft (previously tried 3ft and 6ft, without success, so tried to leave it at default 18ft this time). Press OK.

View media item 7478

8) The console says "Trailer Blindspot Measurements Have Been Saved".

I rejoice and press OK.

No dice. BLIS is still off.
 
Last edited:
OP
OP
G

GeorgeGG

Member
Joined
Mar 9, 2021
Posts
13
Reaction score
0
Location
Boston
Some other things I tried.

* Go into "Towing", then "Select Trailer". There is only one trailer there. I select it. Still nothing.

* Someone posted in another thread that on a 2018 you need to go into regular settings (not towing) and check a box "Trailer Blind Spot". On my 2020, there is no separate option for "Trailer Blind Spot". There is on option called "Blind Spot", but it does not let me select it when the hitch electrical cable is connected.

* Read in another thread that the trailer type must be set to "conventional trailer". I even remember setting this myself when fighting with the menus earlier. But this time it did not ask me to set trailer type and I can't find where to set it in the menus.

* Should it tell me somewhere on the console which trailer is connected? When I go into "Towing" -> "Select Trailer", I can select my trailer, but there is no indication that my selection actually sticks.
 
Last edited:

Fizzy

Full Access Members
Joined
Dec 18, 2020
Posts
175
Reaction score
127
Location
Alberta, Canada
I had the exact same issue with our travel trailer. Followed all the instructions, but no matter what I do it says "BLIS deactivated".

Haven't had time yet to troubleshoot it.
 
OP
OP
G

GeorgeGG

Member
Joined
Mar 9, 2021
Posts
13
Reaction score
0
Location
Boston
Thank you, @Fizzy.

@Deadman, you posted in another thread that you have a Stowayaw2 cargo box and how much you love it. Does it interfere with the blind spot system on your expy max? What year is your Expy?
 

Fizzy

Full Access Members
Joined
Dec 18, 2020
Posts
175
Reaction score
127
Location
Alberta, Canada
Just reading the manual again @GeorgeGG - have you checked when moving or just stationary? Page 251 states that BSIS with Trailer Tow switches on over 6mph.

I think I was tinkering with it when stationary.
 
OP
OP
G

GeorgeGG

Member
Joined
Mar 9, 2021
Posts
13
Reaction score
0
Location
Boston
I was stationary when setting it up, but then drove at 20-30 MPH and it still did not turn on. Looking at the manual again, it says that I need to select a trailer type (conventional, fifth wheel or gooseneck). I can't find where to set this any more. Did this once before, but I deleted that trailer and started fresh since then.
 

TheDoug

Full Access Members
Joined
Apr 20, 2019
Posts
527
Reaction score
287
Location
Mansfield, TX
I had something strange like this happen to me with my small utility trailer. I had all the stuff set up correctly in the trailer section... and I reset distance and tried again and again.

Then I looked around in the vehicle settings that turns off/on blind spot stuff (not in trailer section) and checked that box to turn it on and viola it worked.

Edit... went to vehicle settings while trailer was attached still
 
OP
OP
G

GeorgeGG

Member
Joined
Mar 9, 2021
Posts
13
Reaction score
0
Location
Boston
Turned the ignition on and immediately went into the settings menu (not towing). Both Blind Spot and Cross Traffic Alert are checked.

View media item 7479

About 30 seconds later, the system recognizes that my hitch wiring is connected and pops up a message that there is a a trailer connected. I press OK to dismiss the message and the two checkboxes for Blind Spot and Cross Traffic Alert become unchecked with no way to check them.

At this point, I think I need to set trailer type to "conventional" somewhere to make any more progress. But can't find anywhere to set trailer type.
 
Last edited:
OP
OP
G

GeorgeGG

Member
Joined
Mar 9, 2021
Posts
13
Reaction score
0
Location
Boston
It started working on its own. Here you can see on the "Trailer Information" screen.

blis-fixed.png

Also, when I turn the ignition on, it just says "trailer attached" and "cross traffic alert deactivated", instead of "trailer attached" and "blind spot & cross traffic alert deactivated".

For anyone who comes upon this thread in the future, here is everything I did between last night and this morning, although I can't see why any of this would have any effect.

Took the "last night" picture.
Did a master reset of the SYNC3 system (for reasons unrelated to blind spot with trailer)
Shut off the ignition (trailer wiring still connected to the 4-pin connector)
This morning
Unplugged trailer wiring (with ignition still off)
Turned ignition on
In about a minute or two plugged the wiring back in
Wife drove the truck to run an errand. I assume she was driving mostly between 20 and 40 MPH, just like I did yesterday when fighting with BLIS. I don't know if BLIS was already working for her when she had the truck. She drove for about 30 minutes.
Shut off the ignition
A little later I got in the truck and drove on the highway. Noticed that BLIS was working.
Went into "Trailer Information" screen and saw that "Blind Spot with Trailer" had changed to "ready" (although I already knew that the system was working)

Don't know what if anything caused this changed. Maybe had to drive a few miles. Although I drove quite a few miles yesterday too, but yesterday I was also tweaking the menus all the time and deleting and re-creating the trailer. Maybe the trick is to leave the settings alone for a while and just drive.
 
Last edited:
Top