cruise control problems

[GreyGoose006]

the cruise control on my 84 caprice classic is not working.
it never has, but i just recently decided that i want to do something about it.
the vacuum diaphram that connects to the throttle linkage is connected and i can blip the throttle by squeezing it.
i have checked the obvious vacuum lines for cracks and they all seem ok, but there are so many of them that it is almost an impossible task.
i dont see a fuse that is labeled as cruise control, or anything of the type in the fuse box but none of them are blown anyway.
the control on the steering column seems to be connected electrically, but i havent tested it with a multimeter because i have no idea what to test.

i would like to fix it, but i have no idea where to begin or even what to look for, so if anybody has any suggestions or hints, or maybe knows what is wrong, i would appreciate the advice.

any links or vacuum diagrams would be appreciated too...

thanks

[GreyGoose006]

ummm, any ideas?

i checked the fuses again and they are all good, so that isnt it.

[87BoxClassic]

mine doesn't work either

[GreyGoose006]

do you have any idea why?
this is something i'd really like to get working, but i have no idea how or even where to begin.

[silicon212]

First, is it the type that has the speedometer cable in and out, mounted on the left inner fender with the large vacuum diaphragm mounted to the top left rear of the engine, behind the left valve cover, or is it the type that has the multi-wire connector with a cable that attaches to the carb?

Check the vacuum line between the control unit and the brake switch, and check the electric connection at the brake switch. Check your steering column control to make sure the wire isn't disconnected underneath the dash. Check the fuses to make certain that all are in good shape, and check the electric connections at the control unit. Check that the control unit is receiving vacuum.

[GreyGoose006]

its the first i think. i dont see a speedo cable tho, i see a throttle linkage that is connected to the diaphragm. it is mounted on the inner drivers side fender.

i'll post pics, since this is pretty impossible without them.

[GreyGoose006]

close view.
i circled the vac line i think you are talking about.




big view.

the dotted line is the line that connects the diaphragm to the trhottle linkage.
i dont see a speedo cable, but it might be there.

[silicon212]

You have the later system that's electronic, doesn't use the speedo cable.

Check and verify that all electrical connections are intact, all vacuum lines are intact and that the control unit is operational.

I didn't know that your car has a V6. 3.8 liter, correct?

[GreyGoose006]

yeah, 229 CI.

how can you tell?
manifold?





ok, so to check the connections, i should use a multimeter correct?
where do i connect it to check things?
i'm new to electronic troubleshooting.

[silicon212]

1984 was the last year for that engine, the 4.3 liter engines are all FI.

The giveaway is basically the air cleaner and the PCV breather tube on the left valve cover (305 has the tube on the right side, as with other 1969-up small blocks). Of course, that ultra-deep fan shroud is another giveaway to it being a V6.

[GreyGoose006]

wow. trivia.
i hate that engine.
its so much trouble, and its not even powerful.
although, the exhaust sounds very menacing for some odd reason.
very V-8 ish.



back on topic, how do i test the electronics

[87BoxClassic]

someone said the cruise control only works over 45 mph is that true?

[GreyGoose006]

there may be a limiter. i dont know because mine has never worked, but it would make sense to have one. i've tried it at over 65.

[PeteA216]

Hey, I know I'm butting in here kind of late in the game, and I'm sorry about that, but The cruise in my '84 stopped working about a year ago. Just completely out of the blue, decided not to work for me one day. Well, I never did get it working. I have the exact same setup as you Grey Goose. I guess I'm asking Silicon here, will that setup work without the ECM. It stopped working about 8 months before I even decided to tamper with the electrical aspect of the engine, but now that its no more, does that mean I have no hope of ever getting the cruise up and running again?

PS, Grey Goose, a great way to see if the vacuum hoses are holding up it to take a vacuum pump directly to the hoses conencting to your cruise unit. If they hold vaccum, you're good, if not, yah gotta trace the leak.

[silicon212]

The cruise control system is completely independent of the ECM.

I seem to have misplaced my Haynes book, so I can't look up right now what makes those things tick.