[bobandpeni]

My friends frequently ask me how I learned to fix so many things.  I usually answer, "because I've broken so many things!"

I'm not sure if this fits into the "broken" category since technically it wasn't broke.....but I had to fix it anyway.

If you want the short story, skip to the end.  Otherwise read it and weep.

Last year, before our 3000 mile venture in our '72 classic, I had some engine work done.  The day before our venture my wife asked me to replace the tail lights with a set of LED lights that I had purchased.  The original lights were painfully dim and she was worried that no one could see the brake lights in the daytime.  I obliged and replaced the lights.

Next day, as I'm getting on the highway the darned cruise control won't work.  DANGIT!!!!  I assume that the engine shop broke/cut/fried something and each night on our 3 week venture I would try to save my right leg from further pain by attempting to trouble shoot some part of the cruise only to resign that the circuit board must have fried.  Naturally upon returning home I purchased a brand new Rostra unit from eBay with a 3 year warranty to be installed this winter.

Of course I was busy with other projects this winter and did not get it installed.

Fast forward to the beginning of March and once again I'm pressed for time before we take the coach on our first outing of the year to Kentucky.  I carefully pull out the old unit and vacuum actuator (the control stalk was removed when we replaced the steering column earlier in the year....say, other projects!) and re-engineer the installation of the new unit with an electric throttle control.  I get it all neatly installed the night before our trip, of course I can't test it since my dear bride is loading the coach but what could possibly go wrong, I installed it EXACTLY as the instructions directed and I'm an expert at wiring now that I have at least 500 HOURS! wiring this or that on our classic coach!

Didn't work

My right leg again suffers the rigors of the trip, albeit a short 300 miles each way.

Once I get to Kentucky I start reading the TROUBLESHOOTING section of the owners manual where it clearly states that the unit needs to see a ground through the brake light bulbs and if you have LED's it will not be able to do this.  I'm thinking that would be a nice thing to

include in the INSTALLATION SECTION!  Once I calm down I drop the eBay seller a note and he kindly sends me a relay (free of charge...he must have felt my pain) that will fix everything and get me going down the road.

......which also means that the OLD unit was probably fine and didn't need replaced after all!!!!!!!

So......

If you install some nice bright LED brake lights in your classic coach and suddenly your cruise doesn't work, you're (probably) going to need a brake light bypass relay.

[HoosierDaddy]

Good info , Bob. I put a Rostra electric servo unit in my 1978 Newell. It worked very well...

[kyleb]

Bummer you had that issue.

My King Cruise control instructions said for LED brake lights - add a regular filament bulb or a resistor so the cruise unit would get it's ground that way.
I am still installing it - I have the mechanical done & most of the wires on the coach identified - Now to connect the wires.

Always something . . . . .

[Richard]

I would add to this thread that on my coach I installed bot rear and front led lights, meaning the mechanical blinker flasher would not flash. An electronic relay fixes that. Dumb me, I didn't think to check the emergency flashers. They also would not flash, so I needed a second electronic relay.

If you have led lights, check to make sure your flashers work, you don't want to find out in an emergency that they dont

[bobandpeni]

Richard,

Good advice! I was rather thorough in verifying everything worked after installing the LED tail lights, signals, running lights, brake lights, and yes the flashers all worked. I did not have to replace the flasher relay as I still have incandescent bulbs on the front and sides so all is well. It all got rechecked when I installed a new steering column this winter.

Unfortunately it never occurred to me to check the cruise control and that cost me a new unit. Maybe this one will work better than the vintage unit as it was not really fast or powerful enough to operate the throttle adequately. At least I didn't throw away the other unit and may be able to repurpose it.....maybe my lawnmower.....LOL

[medcrest]

I would add to this thread that on my coach I installed bot rear and front led lights, meaning the mechanical blinker flasher would not flash. An electronic relay fixes that.  Dumb me, I didn't think to check the emergency flashers. They also would not flash, so I needed a second electronic relay.

If you have led lights, check to make sure your flashers work, you don't want to find out in an emergency that they dont

I have a coach just slightly older than yours.  I bought led brake and turn signal lights that I haven't yet installed.  I'm slightly confused about this post.  Does this mean that the mechanical flasher unit was replaced by an electronic relay or supplemented with an electronic relay?  In either case, what relay did you use?

[Richard]

Replaced.
https://www.amazon.com/gp/product/B00270...UTF8&psc=1

There are others, but you need a square two prong model to fit on the panel. The flashers are located in the panel at the passenger footwell. You should get two since the flashers and the blinkers use separate ones.

[Chester Stone]

I changed all of my rear lights to LED, but not the other side and front lights, thus no problem with the flasher. However, I do have a problem with the cruise control not always disengaging when the brakes are engaged. I wonder if this is a LED ground problem. Also, I had trouble hearing the flasher and often forgot to turn it off. I solve the problem with an new flasher that make more noise, but cannot recall where I purchased it.

[bobandpeni]

Chester,

Disengaging the cruise should not be affected by the LED ground (or lack thereof).  The cruise should be disengaged by 12v from the brake lights when they are on, the same applies if you have a clutch.  A hot wire supplies 12v to the brake light/clutch switch and when the pedals are pressed down the switch closes and completes the circuit.  Your brake disengagement circuit on the cruise control should get 12v when the pedal is pressed and 0v when the pedal is up.  I'd check the integrity of that circuit first.

[Chester Stone]

Bob, I think you are right. I suspect the brake lights does not come on unless the brakes are strongly applied. Probably need a new brake light switch.