I often wonder why the Driving/passing lamps are made to turn off when switched to high beam. 1991 Ultra. That being said, I would like to change that. I have a wiring diagram and do not see where the driving lamps run through a relay?
Is there any reason why I should not modify so that my driving lights work on low AND Hi Beam? Has anyone before me done this and can save me some steps? Just thought that I would ask before getting all serious.
Thanks .... Frank

 

I don't see hooking up Driving Lights could be that difficult. I all most Did it to my Heritage, but sold it before the hook up.
I was going to run a Fused hot wire and a ground wire directly from Driving light switch to battery and Disconnect Factory Electrical hook up.

 

maybe this will help ...

 

A simple relay in the bucket will fix this.
Harley also sells a plug and play kit it can be found on the internet too.
Plus as an after thought you should use LEDs to reduce the load on the wiring
or you'll need a new fused circuit.

 

I suspect it was done because of the additional current drain of the high beam. Usually the high beam is like 55 watts and the low is 35 watts (about). However, if you go to LED you can wire up the passing lamps to run all the time. That is what I did on my 1992 Ultra

 

It was done because it is illegal in some places to have auxiliary lamps that work when the headlamps are on high beam.

 

I did this on my '95 heritage by simply running a hot lead to one side of the switch that controls the driving lamps.
I'm still running incandescent lights and have had it in this configuration since '09 without problems.

 

Just like factory installed fog lights on passenger cars/trucks. The fog lights shut off when the high beams are on.

 

Some jurisdictions do not allow it, so the default is they/don’t work together.

 

Learn something new everyday. I wonder what the logic of that is.