Enabling Headlight "Flash to Pass" in 10 Minutes or Less

patrickt · #1 (**permalink**) 05-30-2021, 01:37 PM

Have you ever just wanted to flash your headlights, but without having to turn the Lucas dash switch on and off? You know, just by tapping the little switch on the back of the turn signal stalk so that you can signal somebody with your headlights. Most of our other cars have this ability, and we used to call it "flash to pass" functionality and it was built in to the headlight dimmer switch, but not our ERA cars. So, is it hard to add this nice little touch? Will it require a massive amount of rewiring? Of course not. In fact, only one wire.

The pic below is of the VW signal relay on our ERA cars. ERA wires them so that terminal 30 and terminal 56 are connected. Both terminals are energized when you turn the Lucas dash switch on. If instead you have terminal 30 ALWAYS ENERGIZED and leave terminal 56 to be energized when you turn the Lucas dash switch on, then you will enable the "flash to pass" functionality that is actually built in to the VW relay. The relay is really a beautiful little component; a latching relay with flashing functionality. Wonderful. Now, if you would like to just "test out" what enabling "flash to pass" is like, pull the wire off terminal 56 as you see in my pic, then turn the Lucas switch on as if you were turning the headlights on (the headlights will not be on because you have pulled the feed wire off). You can now test out with the stalk control switch how nice it is to be able to flash your headlights without having to turn on the Lucas dash switch. Just put the wire back on when you're done testing.

To enable FTP permanently, just pull the lead off terminal 30, tape that wire off, and run an always HOT lead to that terminal. That's it. Maybe a 10 minute job. Yep, that's the way it should have been wired to begin with, IMO. But Bob P. did such a wonderful job on the wiring that I can't really complain. So, there's your ten minute upgrade... thank you very much.

eschaider · #2 (**permalink**) 05-30-2021, 03:20 PM

Very nice detective work there, Patrick.

Ed

Gaz64 · #3 (**permalink**) 05-30-2021, 05:40 PM

Quote:

Originally Posted by eschaider

Very nice detective work there, Patrick.

Ed

Good work.

Poor design if 30 is not connected to battery.
All the heavy current is still going through the headlight switch.

patrickt · #4 (**permalink**) 05-30-2021, 05:43 PM

Quote:

Originally Posted by Gaz64

Good work.

Poor design if 30 is not connected to battery.
All the heavy current is still going through the headlight switch.

I eliminated that flaw previously in this thread: Headlight Wiring Upgrade I wouldn't trust even 10 amps going through a Lucas toggle switch.

Gaz64 · #5 (**permalink**) 05-30-2021, 06:03 PM

Quote:

Originally Posted by patrickt

I eliminated that flaw previously in this thread: Headlight Wiring Upgrade I wouldn't trust even 10 amps going through a Lucas toggle switch.

Yes, I know you already did that Pat.

rodneym · #6 (**permalink**) 05-30-2021, 06:20 PM

Where's ERA_Chas when you need him?

strictlypersonl · #7 (**permalink**) 05-31-2021, 06:10 AM

I will consider making that change. I have to worry about legality. In some states, it used to be headlights couldn't be used without the rear parking lights. Now that daytime front running lights are common, the laws may be more flexible.

patrickt · #8 (**permalink**) 05-31-2021, 06:18 AM

Quote:

Originally Posted by strictlypersonl

I will consider making that change. I have to worry about legality...

No worries; I know thousands of really good lawyers.

patrickt · #9 (**permalink**) 06-05-2021, 02:01 PM

As per a request, here is a pic of my actual completed wiring mod. Any time I modify Bob's wiring I like to use an unusual color and I affix a label to the wire explaining what it is. One day, someone else will be under the dash and that fella will appreciate the fact that I labeled it for him.

Note that I used a beautiful shade of purple for the feed wire. That wire leads over to the BROWN wire that goes to the Lucas light switch. Maybe an eight inch run. That's a really easy, convenient source of always on power and it makes intuitive sense to feed the FTP relay function with the same power line that feeds the light switch. I really love this mod. I now flash my lights at everybody.