Dealer added cruise control - works!

[Brain75]

Edit: All questions answered. Post #10 has all the meat and 'taters explanations.

Dealer added cruise control - works!

Edit: All questions answered. Post #10 has all the meat and 'taters explanations. https://www.therangerstation.com/forums/index.php?threads/dealer-added-cruise-control.211057/post-2062731 and Post #34 has the final wrap up, thoughts, and PSA. --------------------------------- Recently I got a...

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and Post #34 has the final wrap up, thoughts, and PSA.
---------------------------------

Recently I got a salvaged dealer add on cruise control kit (dealer add on, not factory) from Shran that he saved of a '94 mazda B4000 headed to the crusher.

Everything looks good and I managed to figure out partial part number and get a schematic just from googling (there was no label on the brain box, but later I found out the only label would have been "Ford" - see pic in ebay listing below)...

Part number is going to be something-9A818 where "something" is unique over every single model of vehicle, but the Ford shop manual just refers to them all as 9A818 ...
an example would be E8TZ-9A818-A for "88-91 trucks" listing does not specify full size or ranger/mazda...

Pardon Our Interruption...

Anyhow, pictured in the ebay kit is a speed sensor, and in this shop manual drawing it's part number 9E731

(pic courtesy NumberDummy over on FTE)

The one single thing that stops me from running right out and grabbing one is the SAE connector that plugs into already has a lead on it (coming from the mazda donor).... and all this is doing is supplying a series of pulses. I think the "brain box" is too smart to even care how frequent the pulses are, it just tries to maintain the same rate of pulse is all (I figure that since Ford seems to have one generic universal no matter 4 cyl, 6cyl, no DIP switches, no programming, nothing - they are "smart" dumb boxes) I have to ponder this.... so here's the question for @Shran (dig into that old memory) and of course anyone else who can answer. Couldn't this just accept VSS+ coming out of the EEC-IV computer and skip the extra part? (Is that how it was setup on the Mazda donor?)

here's my "parts pile" - looks like Shran was very good not to pull it all apart and left everything as it lay - which helps a lot for figuring things out.

Pin 1 coming out of the brain box is the red, and pretty obviously power in (inline fusible link sealed up)
Pin 2 is the green and after the butt connector splice is the same gauge and off shade of green as all the brake switch hardware.

The clutch switch is a simple dead man vacuum - once the clutch is depressed ("letting go" of the deadman vacuum switch) it dumps all the vacuum pressure out of that line. Everything makes sense and it looks like a simple "go buy a bunch of vacuum hose and maybe a reservoir"

I ask because well I am cheap I don't want to fry it by just "playing around with it till I get it to work", if anyone knows for sure I much rather hear from them then blindly play around till I screw things up worse.

 

[franklin2]

Those generators that fit into the speedo cable generate a A/C signal. Much like the old distributors with the duraspark system. Not saying it would not work with a square wave, but it would be an "experiment" to see if it would work.

All speedometers were calibrate for 1000 rpm per mile. So there was some standard there. Most cruise controls will not work below a certain mph, so if you got way off it may refuse to work if it thought you were driving too slow.

 

[Brain75]

Hadn't even thought about AC versus square obviously.... 20+ years ago when I put the custom dash into my '48, someone told me that whole 1000 rpm/mi over on FTE but until you said it again I completely forgot that. The speedo in the '48 is a digital with a digital sending unit and gets a holy crap huge number of pulses per mile... when I first hooked it up I put on 270 miles on the odo getting from the shop to the nearest mile marker less than 0.2 mi away.

i haven't found a good "install sheet" that would have been included, but on spark (electronics reseller) and ebay and others I have found a number of NOS kits that do include the install manual - not gonna pay $200 just to get the manual.

I think based on that, and the fact I know where there is one in the junkyard and my junkyards are dirt cheap I am gonna save the risk and just add the extra part... probably grab the vac reservoir off that same unit and then buy new hoses (I am cheap but there is a point where you end up spending a dollar to save a dime and end up doing it all twice).

I was trying to avoid the speed sender unit as I'm lazy and getting to the speedo cable means pulling the dash cluster and doing that means pulling out 35 year old plastic clip without breaking any.... sigh...

re: min speed - The few tidbits gleaned from forum searches specific to the 9A818 says they will not work below 30mph.... but the troubleshooting guide for 9A818 says "test at any speed greater than 25mph".

 

[Brain75]

BTW, sparksurplus is one of the electronic places that carry a buttload of these for anyone hunting:

Electrical: Cruise Control

Discount open-box and surplus auto parts at huge savings. New Old Stock, Aftermarket, Remanufactured and used parts available. We stock everything we sell.

sparksurplus.com

 

[Shran]

Not knowing very much about how cruise control works, I assumed it operated solely off a vacuum signal. You set the speed and it tracks a vacuum reading, if vacuum reads higher it applies more throttle, and if it reads lower it lets off the gas. That was simply my assumption though.

I think your Power wire and one other had to be cut as they went through somewhere that they couldn't be pulled out of in one piece.

 

[franklin2]

Not knowing very much about how cruise control works, I assumed it operated solely off a vacuum signal. You set the speed and it tracks a vacuum reading, if vacuum reads higher it applies more throttle, and if it reads lower it lets off the gas. That was simply my assumption though.

I think your Power wire and one other had to be cut as they went through somewhere that they couldn't be pulled out of in one piece.

They all monitor road speed in some form or fashion. Monitoring vacuum won't do it.

 

[Curious Hound]

I don’t think vss will work. The box does care about the frequency of the pulses. It has to. If it’s looking for speeds in the range of, say 0-400rpm and it’s seeing 700-1500 rpm, it’s probably going to be confused. Yes. It’s just looking for a reading so it can open or close the throttle. But it probably has a certain operating range. These were very simple systems in the infancy of cruise control. It’s best to give it what it wants.

I remember adding cruise to my 1983 Eagle. There was a magnet I had to attach to the drive shaft for the sensor to read. That system worked well.

 

[Brain75]

well I have an apt. wed to get the windshield replaced, on the way there I will test the cruise with just that little weird pigtail, if it works it works... if it doesn't I know a 'yard on the way that I can get the speed sensor (as long as they haven't crushed it in the last 2 weeks).. If they crushed it, well I can either shop the yard or get one used/NOS somewhere since we know the part number.

I figured out why Ford has 200 kits that are all "random number-9A818" each and ever model has a different clutch kill switch BRACKET or the stalk on the column is different or it is a set of buttons on the dash - too many differences in floor pan for them to have a generic bracket and not all have enough room on the column... That said, it looks like they are all the same brain boxes and speed sensors, etc etc - the actual meat and potatoes... The bracketry under the hood is "not quite right" for my 2nd gen, so I figure I will grab a factory bracket from the yard to make it clean and not rattle - my 'yard is real cheap on dumb parts like that.

 

[Brain75]

Not knowing very much about how cruise control works, I assumed it operated solely off a vacuum signal. You set the speed and it tracks a vacuum reading, if vacuum reads higher it applies more throttle, and if it reads lower it lets off the gas. That was simply my assumption though.

I think your Power wire and one other had to be cut as they went through somewhere that they couldn't be pulled out of in one piece.

FWIW, The more I think about it I can't see how working solely off vacuum would work on anything but a perfect fresh from the factory motor... an intermittent miss, worn rings, etc and vacuum goes all over the place people would be constantly taking it to a shop to "get the cruise fixed" if it was anything other than a lab machine or a brand new first 10k miles.

If the power wire wasn't cut it would still have the truck attached, no?

and yeah the brake switch line being cut made total sense, you can't get it routed or un-routed without cutting it.

My guess, the PO of your mazda had it quit on em and they basically disconnected and left in place without trying to fix it - hence the missing speed sensor and quite possibly my little "weird pigtail" is the chopped remnants of that line.

 

[Brain75]

Update: Cruise works!
I went to the junkyard, grabbed a speed sensor (off an F150 with dealer added) and drew up a schematic of how a factory cruise was done in a 3 different 2nd gen ranger/bronco iis first.
All the factory ones (that were intact) had a check valve between the manifold and the cruise system close to the engine manifold. Grabbed a check valve and headed home.

I wired up all the vacuum, and looked at the brake switch for a while trying to figure out if it was normally open, normally closed (it is 3 legged, and the 2 taps used look like it is the NC side) and which what that would mean to wiring (do you give it ground or power, and do you connect the switch so it is normally closed when the brake is up or normally open)... Decided to just plug in the box and see if it had continuity or voltage coming out of the box.
It had 6v coming out on that green (brake switch) wire... so I put a couple pigtail alligator leads and took it for a test drive without the brake switch at all.

The green/brake circuit must be closed to ground or else it will not turn on. If you open that circuit it immediately turns off cruise.

The clutch vacuum line appears to either be slow or busted in the brain box. When you depress the clutch it dumps all vacuum out of the system (and the engine manifold)
the engine bogs for a split second then the cruise wraps it up to 5000 rpms before disengaging.
Note: Coming from Shran it only had one single vacuum hose and it looked like it was direct from manifold to servo, all the clutch stuff appeared to be unused.

So, 99% working, only thing to remember is if you try to downshift on a hill tap the brake too to disengage cruise.

I still have to do something with the brake switch because bracket just wont work with a 2nd gen (came out of a 3rd gen), nothing to connect to that I can figure out - have to fabricate.

One thing about it that might be 100% my fault, might just be an issue with these systems. I set the cruise at 35, it engaged at 36 and you could feel it constantly surging back and forth between 36 and 37. Might have been slop in the throttle from my choice of how to linkage the throttle cable... might be the brain box is kinda slow and over-reactive.

Oh I also grabbed a mounting bracket for the servo/reservoir at the 'yard. Since I was buying a tilt column they just waved at that little piece of metal and said "don't worry about it"

Total cost $80... $50 for the parts from Shran, $10 for shipping, $10 for a speed sensor, $6 for a roll of vac hose and the rest was all taxes, fees, shipping insurance, epa duties, etc.

 

[Brain75]

ya know at first I was thinking I would just live with the clutch switch not working (we had one on the farm that was like that, so to me it would be just like driving the ole '86, my brain already has the wiring), but the more I got to thinking, for another $1 a guy could add a 2nd NC switch inline (wired in series) with the brake one and then either pedal would cause the same disconnect..

https://www.aliexpress.us/item/3256808055192937.html

 

[superj]

this is the only thing my truck is missing, cruise control.

 

[Shran]

Nice. Glad you got it working.

I think a little bit of surging is normal with aftermarket cruise. This being a Ford kit I would expect it to be a LITTLE better, but... it's still an add-on. I had cruise added to my 2010 Silverado at work and it has always been like + or - 5mph... kind of annoying... and that's a drive by wire truck.

 

[Brain75]

I'm very sure it (the throttle surge) was my zip tie wiring up of the throttle linkage. The brackets were pretty obvious, but turned 90 degrees wrong to mount to anything on the engine... yet another difference between 2nd gen and 3rd gen I figure. I was thinking about a better bracket I could fabricate and it occurred to me it might be a whole lot quicker & easier to just grab the throttle cable/linkage only from one of the 2nd gens in the yard. The servo they want money for ($20+), but the linkage itself is to them just another wave and say "whatever" I bet. The throttle cable has a cotter pin connector at the servo and if the factory one is the same they can just be swapped easy as pulling a pin.

 

[Brain75]

this is the only thing my truck is missing, cruise control.

2004, you should be able to do it with junkyard parts and following the guide here on TRS...
the 2nd gens have some limits if you don't have it from factory, the steering column has a square 4 pin connector (the 4th pin is the cruise buttons), but the wiring harness on the body has a round 3 pin connector.... so even if I had grabbed every last part from a junkyard truck the wiring and brain box would be an issue, 3rd and 4th I kinda gather is all pre-wired.

Adding Cruise Control To Your Ford Ranger - The Ranger Station

Disclaimer: The Ranger Station.com, The Ranger Station.com Staff, nor the original poster are responsible for you doing this modification to your vehicle. By doing this modification and following this how-to you, the installer, take full responsibility if anything is damaged … Continued

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