UPDATE; Cruise control quit engaging....SUCCESS!

[John Schmidt]

So far I haven't pinned down why. It's been on there for over 10 years and the only problem I've had was a loose ground wire that made it intermittent. Some needle nose pliers fixed that and has been trouble free ever since....until now. I did some voltage checks and it seems my servo may be on the way out. Here's what I came up with so far;

black-grnd.=OK
red-12v=OK
brown-12v w/ignition and cc both on=OK
purple-5v all the time, not just when I hit the brake. Should be 12v w/brake, 0 vdc when released.
green-11v(s/b 12v) when set/coast is pressed, 0 vdc when released
yellow-11v(s/b 12v) when resume/accel is pressed, 0 vdc when released

The slightly low voltage for the green and yellow wires may be due to a low battery but doubtful since other readings showed 12v.

I can't remember, can't find it in the manual, what's the deal with the little red LED inside the servo? When is it supposed to light up, mine only comes on when either "setting" or "accel" is pressed. I have LED's both front and rear so have installed a relay for grounding purposes and has been trouble free all this time.

If someone has their CC installed in such a manner they can access the wiring easily for comparison, or if anyone has some suggestions...I'm listening. Don't really want to replace the servo since it involves pulling the tank and airbox. If I do that, I might as well address some other stuff I've been putting off but not really looking forward to it in any case.

NEW QUESTION: Can someone check the voltage at the purple wire if you can get to it easy enough? Mine is reading 5vdc which seems pretty low but since it's been on there for over 10 yrs. I have no idea what it was originally. To function as a servo cut off it may not need a full 12vdc. Mine is grounded through a relay since I have LED's all around except the headlight. I suppose it could be the servo is going south on me, sure hope not but c'est la vie....that's life!
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UPDATE: First, I pulled the innards out of the servo and cleaned the internal passage in all three solenoids. Checking the circuit board with a strong glass didn't reveal anything obviously wrong there so put it all back together. Thinking back, a few weeks ago I removed the load equalizer since I had installed a new self-canceling unit from Signal Dynamics which doesn't use the OEM flasher at all, has its own built in. FWIW, it won't work on the single circuit type for turn signals such as Honda uses. I adapted HD controls to my Valk years ago so have independent left and right circuitry.

Everything worked fine re. the turn signals, self-canceling, etc., but until a few days ago I never had tried to use the cruise control. It simply would not engage. It didn't make sense so I spent the last couple weeks trying one thing after another, to no avail. I finally figured the only real change I had made was the removal of the load equalizer so yesterday I picked up a couple 100 ohm, 10 watt resistors and installed them in parallel with the two rear turn signal wires under the right side cover. A short time a go I took the bike around the block and....BINGO....it worked. So, now I'm going to install a regular multi pin connector and mount the resistors in solid. Next problem, the light on the speedo just went south which involves removing the fairing to get at it. Sure hope that's the end of it, weather is too nice to not ride.

[Firefighter]

Mine would set sometimes and not others, then would not cancel with front brake, turned out to be the front brake switch. Was on a trip when the problem started, I was trying to diagnose while on the road, pulled wires to front brake loose but still wasn't sure. Once I was home I replaced the front brake switch and it has worked ever since.

[Valkpilot]

Mine would set sometimes and not others, then would not cancel with front brake, turned out to be the front brake switch. Was on a trip when the problem started, I was trying to diagnose while on the road, pulled wires to front brake loose but still wasn't sure. Once I was home I replaced the front brake switch and it has worked ever since.

+1 on checking the switches.  I had a rear brake switch that failed "on" meaning the brake lights were always illuminated.  The cruise control won't set in this case, which is how I discovered the problem.

[John Schmidt]

I believe I'm SOL. I've checked everything, voltages are in line with all the reading material I've found. I took two last steps; first I disconnected my red strobe light type LED's that come on with the brake. Just fishing on that one and as expected....no change, no engagement. Next I connected the purple wire directly to ground and went around the block. Waited until I was on a straight stretch and turned on the CC at the handlebars. Again, no joy. Tried recycling 2-3 times with no change so headed back to the house. Not sure why it would make any difference, but a couple weeks ago I changed out my self-canceling Penta Star unit and was then able to remove the equalizer I had installed the last few years. Since I have HD controls on the bike I can use the self-canceling unit, something the Honda circuitry won't support. Wish there was a method of testing the servo without removing it, sorta like putting the bike on the center stand and running the bike...something I won't do. I just want to watch the servo action to see if it actually pulls on the cable. Guess I need to go looking for a replacement, it's been flawless for well over 10 years.

[Cracker Jack]

John, I don't believe you said whether you have the MC cruise ot the popular auto aftermarket one. I'm not sure it matters because I think they are ths same servo unit.
I copied the attached link attached link several years ago and fairly recently decided to pull and work on my MC Cruise after mine not engaging for 2-3 years and not being able to get it working otherwise.

http://www.vulcanbagger.com/forums/showthread.php?t=19536

Unfortunately, the pictures don't show but you may be able to figure the procedure out with the verbiage in the link.

The servo is easy to take apart and reassemble. After I did mine with total success, I could have kicked myself for not doing it when the problem first happened.

My biggest problem was digging into the innards to get to the servo. Once in there, the repair was easy. Probably was the reason it took me so long to bite the bullet.

[Cracker Jack]

Let me add that the indicator lights on mine were working indicating that power was on and that the unit was engaged when I would try to engage control. If yours does that, it's almost a sure bet that the sticking vacuum valve is the culprit.

If you have lights and they don't indicate a working unit, probably something else wrong.

[John Schmidt]

Cracker Jack, everything lights up as designed so you may be right re. the valves. I just hate the thought of pulling the entire unit out for that since it involves pulling the tank and airbox, then disconnecting the chain from the carb linkage. Since I have a bit of slack in the cable where it goes around the overflow bottle, I might be able to pull it up far enough to disassemble while still on the bike. Going to try at least. We have a pizza party get together next weekend and I was hoping to get out on the road to attend now that the temps are down. Really bugging me....I know, I can still ride without the CC, just bugs me. 

[John Schmidt]

Today I removed the guts and cleaned the solenoids as shown in the link posted. Once tested, still no action to I removed the guts again and plugged the vacuum line. Taped over the connector and closed it up with the cable still in place. I can at least ride the bike until I make a decision on my next move. In the mean time I'll do some clean up of wiring after which I might try one more time. It's a bit frustrating! 

[Cracker Jack]

I tried to send you a PM, don't know if I'm smart enough to be able to get it through. I need you to call me or give me your number.

[John Schmidt]

Got it....replied.

[John Schmidt]

Bump for update.