Let me see if I can explain better.
# 1. We had been on the road about 15-20 min. through stop and go traffic lights. NO problem Cruise control NOT engaged, I entered the Highway traveled about 6 miles, again NO cruise control engaged, when we were coming to another stop, I pressed down on clutch and began to apply brakes as I down shifted to say 2nd the RPM jump to 25oo while the clutch was pressed to the floor and my foot was still on the brake peddle , I hit the brakes harder to release the vacuum, be cause that is what disengages the vacuum release switch for the cruise control. (If my foot had been on the brake and gas at the same time as I pushed down on the brake the RPM would have continued to rise in stead of rapid decline.)

#2 In the prior incident I was driving at about 60 mph, again NO cruise engaged, when I felt the car pull forward under cruise control power and the throttle peddle moved down. (vacuum kicked in)

#1 occurred when vacuum was on increase due to deceleration.

#2 should not have occurred.

both are related to vacuum issues. OR the cruise unite is bad???

The cruise unit does not always engage, this may be due to vacuum or the cruise unit internal connections.

The brake switch disengages the electrical connection upon applying the brakes and the vacuum release switch breaks the vacuum supply.

 

So here I am warming up the motor and I notice each time I move the throttle linkage the vacuum diaphragm for the Cruise control moves too. I disconnect the linkage.



And it pulls completely back, at ideal. as you see here.

turn off motor and it returns to normal




as seen here.

IS this right/normal operation??? or is something else happening????

IF not normal operation then is the Transducer engaging vacuum with out the button being pushed??? or is the button bad causing the Transducer to activate vacuum???? or am I not looking at this right???
Vacuum tubs go to 4 way connector, one leg goes to transducer, one to the diaphragm, one from the manifold the other to vacuum operated devices.???
SO this is normal....
The fact that it works now and then means the wire connections are good to the transducer???So a test light at the transducer engage connection, should show power. Question would be on the hold connection????
Yes...No???

 

Turns out it maybe the memory chip circuit of the control unit operating the vehicle.....Me.
Forgot the order in which buttons are pushed.

 

a couple things jump out,
1 the brake switch you said you have to press hard to activate the switch?
no, should disconnect with very little pedal movement.
2. electrical snafu?
short? system should not engage itself.
3 vacuum?
vacuum can should not move like it did,
4 hoses? right? maybe the vacuum control on / in the transducer is leaking
or the hoses are not routed correctly?
no way that can should move unless the transducer needs to hold a speed.

sorry, keep looking

 

OK..So the manifold Vacuum goes to the port on the face next to the port that goes to the 4 way fitting, which connects Servo, Vac. Relief valve and side port (Brass). AND in NO way should the Servo move until engaged.

Since I rewired with new color coded wires to make sure it is correct and rechecked the vacuum tubes and their connection to ensure it matched the diagram shown. Both Brake and Relief valve switches are new.

The Diaphragm moves with vacuum as throttle increases means there is a Vacuum in the line which means there is leak in the Cruise Control unit. THERE SHOULD be NO movement of the Diaphragm until engaged to hold a speed...RIGHT.

I had a Ford Bronco once that would engage and apply the brakes at will with out warning due to a leak in the Power Booster for the brakes.

That kind of puts it on the Cruise Control unit being bad.
In any event I have disconnect servo rod from throttle, safety.

Thanks for the help.
DB

 

SEE above for more on this

 

Well, I replaced the cruise unit, rechecked the wire connections, tapped off a questionable pair. Turned on ignition and had wife operate cruise button on turn signal/column.
1st position engage: test light on.
2nd position hold test light on and I hear a click from cruise unit.
3rd position: press brake peddle test lights go off.
4th position: press button all the way in and it clicks, hold button test light goes "off" then, "on" when returning to mid point.
Take for test drive: all works good....engaged several times looking for problems. none.
TODAY>>>>>Start car, idle to warm up. get in car press throttle rpm runs high by it self, about 2500 before I press brake to cut acceleration, each time I press throttle rpm runs high by it self. Back in garage, wife starts car, cruise diaphragm pulls throttle back. turn off car get Test light, Check leads at cruise unit.
Engage, white wire, NO light. BUT the brn Hold wire will light up. Press button to engage no light, but hold position lights up....

The cruise button is the only thing I have not yet replaced.

During the test drive yesterday, I set cruise at 60 mph, I was clocked at 53 mph. I adjusted to vacuum orifice per instruction "out" to bring cruise speed up to set speed "In" to reduce cruise speed to set speed
This should have no bearing on short in cruise button.
I think it is the cruise button. That is the only place all connection converge.

 

sounds like you are making progress.
i admire your stick to it-ness

 

More like stubborn/ bull / hard headed. Fix it or break it. approach.

I find there are no Turn signal levers w/cruise & T&T to be had.
Not made any more. I am not sure which one I have either, other than the lever is bent at an angel (which I believe I read makes it a 78).
I do not want another used one, cuz that is what I have and it has failed?? I did find one for $119. did not say used or new.
Need to pull str. wheel to see if it is same. I do not know what this Str. Col. came out of other than it is a GM. Orig. was stock straight column.

Thanks for listening.
DB

 

Determined which one I had, ordered replacement, (NEW) $137.
Have old one 90% out of column. Just wait now.
If this is not problem, I'll do with out.

DB

 

my fingers are crossed.
i reached the do with out stage too.
i need a whole new transducer and the pain of swapping it
at a time when i haven't put an overdrive tranny in yet,
just didn't float my boat.
when i get the tranny done, i will tackle the cruise.
good luck

 

A 5 speed??? that would be nice. What is it out of??

 

no, 4 speed auto
200-4r
if i went manual, 6 speed. :droolie:

 

Well..I received the new turn signal lever w/ Cruise and T & T.
Spent some time trying to fish the connector head up from the bottom of the column. I am using 20lb fishing line doubled. IT will not pass through the column and I am afraid to pull to hard and break the wires. It feels like it plastic connector head is to big and will not pass by something. The wires move just fine no resistance.
SO.. I am thinking separating (cutting) the lever from the wires near the top of the column and splicing & soldering them to the new lever wires.
Since the wires were not the problem it should not be a big deal???
I have to get some thing called a cold heat solder pen.

DB

 

I know this late, but, I just read several posts concerning Cruise Control and Manual Transmission.
1st. They were not offered on the 4 speed manual trans.
ONLY on the Automatic.
This had to do with the constant vacuum, that a clutch did not provide.
So why did I think I could put a (CC) in a manual Trans setup???
Because I did not know better and no one ever said anything about it.
SO if I travel to Las Vegas on the open highway, NO traffic, then if it works OK. IF not, I may just take it out.