When I go through the procedure to set lash on the cruise control, I hold the switch to resume, the light turns green, I start the bike and the light flashes red/green very fast. The lash procedure won't work.
I installed a new handlebar switch and got the same results.

I actually removed the module and plugged it in on a friend's bike. His light operated correctly with my module.

 

That’s not all the right steps.

https://www.fixmyhog.com/post/harley-crusie-control/

Lash just sets how quickly the cruise control starts working, by giving it a base line response target. It’ll work, regardless of this lash adjustment. You’ll just have a delayed initial response or engagement.

So, is your cruise control working at all?

 

No, the cruise won't work.
When i go through the diagnostics, everything checks out. It just won't work.
For ***** and giggles I disconnected the roll off switch. The brake lights aren't stuck on either.
The bike started losing the cruise when it rained, but an hour later it would work. I suspected the roll off switch, so I changed the cable...the switch checks out, but no go.
When I turn on the ignition with the reset button pushed, the light comes on green. As soon as the bike starts up it begins to flash red/green, like there's a loose connection.
I've been through the wiring from the handlebar controls to the module.
I don't find anything.

 

What is lash?

 

It's the difference between the throttle cables and the slack in the Cruise Control cable. If you have to much slack in your cruise control cable then when you go to set your cruise at 60 mph, the cruise control with excessive slack will allow the throttle plate to back off and it may hold it at 50 mph. You would then have to push the + button up until you reached your desired speed. If the slack is taken out of the cruise cable then when you push your cruise button the throttle plate won't move and it will maintain the same speed. The Cruise Control unit is separate from the throttle cables on the older bikes and is usually mounted under the left side cover on touring bikes and the cable runs over the motor to the right side of the bike.

The newer bikes have a different set up and are controlled thru the Canbus system I believe. That's how you are able to install cruise control on the new Softails. On the old ones there wasn't enough room.

 

I'd suggest first physically looking on the right side of the bike (behind the air filter) to make sure the cruise cable is still hooked up. Then, check how much slack there is in the cable.

I think when you do the cruise adjustment, you also need to hold the +/- switch until the idle speeds up and then slows back down. That's how the system knows where to set the cable. Also, I think it's supposed to flash those two colors before initiating the +/- button. I think....... (edit--- found the procedure. See below)

 

When I do that procedure is when I get the flashing indicator.
I'm wondering if it isn't telling me the module is bad...but nobody has been able to tell me.
I tried a used module from ebay, but it does the same thing. Who knows, it could have been bad also.

 

what does the cruise control do when you try to use it normally? Including what lights you see displayed when you turn it on, and when you try to engage it?

 

I get the red cruise control light, but the cruise won't set at any speed.

 

Have you disconnected the battery? Won’t hurt to try.

Since the module worked on another bike, but not yours.....I suspect something else.

I would go through the troubleshooting procedure lined out for the cruise control.

Sounds like a cable issue to me....