Making the trailer lights work

Making the trailer lights work
Complete test setup

I know that Chevy has a problem with owners towing trailers with the bolt .
But they sell a trailer hitch as an accessory????
I have had a trailer hitch on my vehicles since 1974 when I got my first sailboat
A trip to Home Depot for some plywood
Bringing the motorcycle to the track, the uses for the diy guy
Is so numurious that I need go no farther.
I pulled my solar trailer to a mountaintop in VT
With my Prius which is not designed to tow either.

Getting a proper hitch on my Bolt is of high priority.
The mechanical install went very well
Easy to do.
Next we must connect to the car lights.
Started by trying to remove the covers so I could get to the wiring, but it did not go well. Broke two clips getting it out.
So I imediately put it back on knowing that the Bolt had Its first scar and vowed to connect those towing lights in a better way.

Optical repeater tail light controller .

Scrounged in my vast junk pile and found a drawer with CDS photo resistors
The plan is to optically connect the trailer lights by sticking a photo detector
On the 4 signals required.
Stick a sensor on the brake light, the left and right directional , running lights.

I breadboarded a simple op amp comparator circuit with threshold adjustment pots for the 4 sensors.
To do the actual power control and 4 to 3 conversion I used a powered trailer kit that E-Trailer sold me.
The curt converter does the actual power switching and my opto defector interface board generates virtually the same signal that would have been generated if we would have connected directly to the car.
Did some test with the prototype and it looks pretty good so far.
The detector it self is just a cds photo resistor on the end of a small wire.
I’m getting a huge on to off signal but today is not sunny
Lots of detector tweaking to minimize any sunlight or headlights false triggering

Of course the manufacturer could have provided a readily accessible and clearly identified connector , a simple universal trailer control and save a lot of expense for the owner.
Will test further next sunny day.