I've owned my 85 Z28 for almost a year now, and STILL have not figured out why the cruise does not work! This is now really beginning to bother me!

Here are things that I know. The cruise cable is connected to the throttle body, and the cruise switch works (I did the VOM test on the under dash connector and it passed). Other than that, I'm pretty stumped at where to start.

Fumbling with the cruise controls gives absolutely no response, so something is out of whack. Two things that off the top of my head I can think of. First is under the drivers side dash, among the nest of wiring there is a ziti sized hose that makes a whooshing sound when you depress the brake pedal. I think I remember reading somewhere that there is a vacuum hose for the cruise within this vicinity. Maybe this is it and someone unhooked it? The cruise switch attached to the brake pedal is present. Second thing I can think of, will the ECM refuse to operate cruise if there a VSS error? Because it is a throwing a VSS code... Last thing I can think of, someone put an aftermakret Jet "Performance" chip in my ECM. This is the proper PROM for my vehicle, but maybe it has a cruise delete?

Also, I have a seperate post going about a few stray connectors under my dash I which I am trying to figure out what they go to a PO disconnected. Maybe one of these is part of the problem.

https://www.thirdgen.org/forums/elec...ml#post4011900

 

Yes

 

Uhm, OK that's a good start. Where do I hook it back up?



That was taken when I first got the car. The bolt has since been removed from the end of the hose.

 

Since the answer was right there in your post, I quoted your question and answered it as simply as possible. I guess I didn't quote far enough, though.

You'd guessed that the hose is for the cruise control, and, "yes," you are correct. Then you said the tcc/cruise switch on the brake pedal is present. So... that's where the hose goes.

Regarding the connectors in your other topic, the connector in the middle pic is probably the connector for the tcc/cruise switch. I say, "probably," because it's just like the connector that goes to the top of the brake light switch right next to the cruise switch(though the two connectors might be different colors, I don't remember). So if one switch is connected and working, but the other isn't, then the connector in your pic goes to the other switch.

 

When you say other switch...

When I was under the dash I noticed that the bracket atop the brake pedal has two holes for two different switches, but only one switch on the left side is present. The right side is just an open hole. Is something missing?

 

Yes, there's another switch that goes in the other hole. The right hole gets the tcc/cruise switch(auto trans cars), and the left hole gets the brake light switch. And both use connectors like the one in your middle pic... although the brake light switch also gets another connector on the front of it(probably the small one in your third pic, though it's hard to make that one out in the pic).

Apparently your cruise switch is in the left hole. It's on the left side on manual trans cars(but the hole is in a different part of the bracket), so it apparently really doesn't matter which holes the switches go into, as long as the harness' connectors reach the switches ok.

So if only one of those connectors is hanging, then can I assume the wires to the cruise switch is connected? If so, then the white-ish connnector that's hanging goes to the missing brake switch(and it should be white-ish)... and as I said, that other connecter in pic three is probably the other one that goes on the missing brake switch.

 

I'm a bit confused by this, as my brake lights function properly and I can't imagine the car driving normal with the TCC switch missing. So what the heck used to be in that other hole? Also, just to clarify, you stated that the mystery hose connects to the switch on teh brake pedal?

 

I was describing the fix as if your cruise switch was in place, based on your words in your first post:

But now I see why it hasn't made any sense to you. What you called the cruise switch, isn't your cruise switch, it's your brake switch. So apparently it's your cruise switch that's missing, and that's why you don't see where to connect the vacuum hose. So now that we're "on the same page," lol, let's begin again...

The tcc/cruise switch fits into the right hole next to the brake switch on the pedal, and, apparently, you don't have one. It has a nipple for the vacuum hose, and above the hose is where the hanging connector plugs onto it. Now this probably makes more sense to you... and me, lol.

So you need to go to an auto parts store and buy a tcc/cruise control switch for your make/model/year car.

 

Thanks a bunch. I always wondered where all those connectors and that hose went.

Ill report back once I obtain and install a switch.

 

OK searching around for a switch some places say that the brake, cruise and tcc can all be on the same switch?

Now that I think of it, this is the first time I've ever seen a brake switch and there was one sitting in my center console when I first bought the car. It was white and had an orange plunger button at the end.

I'll take a high res picture of what's going on down at the brake pedal when I get home to make sure everyone is on the same page here.

 

On a few 4thgens, everything was on one switch. But on thirdgens, the brake switch is one switch, and the tcc switch is the other switch. The cruise control's vacuum valve is part of the tcc switch.

Getting the correct brake switch depends upon the model year, transmission type(auto or manual) and cruise control(with it or without it). And they're usually white, but some are black.

But getting the correct tcc switch should just be a matter of model year and trans type.

 

OK so It's been established that the switch down there is the brake switch since my brake lights function properly.

The only tbhing that puzzles me is how can the car operate properly with the TCC switch missing?

And this switch not being hooked up is what is causing my cruise control to not function? I was under the impression all this switch did was turn the cruise off when you hit the brake. Unless the ECM does not turn cruise on if the switch is absent for safety reasons, which seems perfectly logical.

 

http://info.rockauto.com/Airtex/Detail.html?1S2833.jpg

Is that our guy? If it is, I'm gonna drop kick myself because I found it in the center console when I bought the car, didn't know what it was and figured it to be a terrorist handheld detonation device, and threw it away...

 

it also controls the tcc , if you drive on the highway then lightly tap your brake pedal watch the tach it will move up about 500 rpms

 

So let's say I've been driving the car around without this switch ever since I got it.

What effect has this had on the TCC/car?

 

i would think it would have no effect on making parts go bad, just a little less gas mileage.

 

So the absence of this switch would prevent the cruise from working at all? I thought It's purpose was to turn OFF the cruise and had nothing to do with whether or not it activated properly...

 

Yup, that's the guy! Did the one you threw away look new? Just tell youself it looked old, because maybe it was the bad one that the owner put in there with the intentions of replacing it, but just never did. So there ya go, you needed a new one anyway, right?

Partsamerica lists it as a "Cruise Control Release Switch," BWD part number CCS2... well, for my '89 tbi, that is. You've never said what year or model your car is. The only reason we know it's got an auto trans is because of the brake pedal pick you posted.

But in searching for it, I check brake switches, too. And I see why you might've thought the brake switch included the cruise control release function as part of the brake switch. Brake switches are listed "with cruise control" or "without cruise control." But that doesn't mean the switch incorporates cruise control. It refers to the car having it or not.

 

It DID look old. Like 24 year old factory part old.

So what are the chances of my cruise control waking up once I put a new one in?

 

As long as the previous owner didn't mess-up any other part of the system, then...

Make sure the retainer(kind of like a tube-shaped washer) is still in the hole in the bracket. If not, you can see the one on the brake switch to know what it looks like. I don't know if you can buy those or not. You might have to pull one out of a junkyard car if yours isn't there.

And make sure the bolt in the hose didn't widen the end too much to keep it from sealing on the nipple of the cruise switch.

Then... let's hope!

 

LA, here is a picture of the brake pedal in high quality to confirm our findings. It looks like one of the switches IS missing. And since my brake lights function properly, that can only leave one more thing.

It is a good thing the retainer is still in the hole. I can't imagine it would be fun to hunt down a part like that.



If you check the "Name That Connector" thread, I posted a higher quality photo of the connector we believe to be the TCC.

The only thing that is puzzling me is how is replacing this switch going to fix the cruise? I know this switch was responsible for turning it OFF but I didn't think it had anything to do with turning it ON.

 

did you ever get this working?

 

Yes the cruise did wake up after I put that switch back in.
Unfortunately, I didn't have time to properly test it as the transmission decided to grenade about the same time the switch arrived.

In two weeks, she will be back with a vengeance and I will post the final results up here (I might need some reminding on that one).