Junkyard Cruise from Scratch - Amplifier Mounting?

[lowspeedpursuit]

So since all the junkyards around here shut down--and a Rostra kit with everything is the better part of a thousand dollars--I'm installing cruise control the most backwards way possible: grabbing all the parts from different places and figuring out the connections myself. I'm taking pictures along the way, and I'll write it up at some point after the holiday, but for now I have a question about the amp, computer, whatever you want to call it. The green box that lives behind the glove box in '93/'94, possibly other years as well.

Does anybody have a good picture of the amp mounted in the stock location? Or even just a more detailed description than "it goes behind the glove box"? The manual shows the amp with the connectors facing left, and this amp came with a little bracket with two screw holes, but behind the glove box there's just nothing there it could attach to. I don't even really understand where it could go without the glove box bumping into it.

Thanks in advance.

 

[fastpakr]

What options pushed the price on the Rostra kit to $1000? It's certainly gone up over the years, but the last I looked they were closer to $300 for the universal kits.

1988-2011 Ford Ranger Rostra Complete Cruise Control Kit

The Cruise Control Store offers cruise control kits for many different Ford model vehicles, including this complete kit for 1988-2011 Ford Rangers.

www.thecruisecontrolstore.com

 

[RonD]

You would be better off using a 1995-2003 Cruise unit
Actuator in the engine bay is also the controller(amplifier)
Just 2 wires from steering wheel buttons
2 wires from VSS
Ground and 12v key on
And brake pedal shut off, with clutch pedal pass thru if manual trans

On my 1994 the Cruise amplifier is above gas pedal to the right, mounted on firewall with a bracket

 

[lowspeedpursuit]

I swear back when I cross-shopped, it would have been double that ($600-some) for everything from Rostra, but it's also possible I'm misremembering, or was just being dumb and looking at the wrong thing

In any event, this is one of those projects that sat on the shelf for over a year before I actually had any time to work on it. I've already got the major pieces of a stock system, from '93/'94 donors, and I'm only into it for something like $40. I just need to mount the amp and servo in my truck and sort out the wiring. If the Rostra kit is that much cheaper than I thought, then I can't imagine finding newer donor parts would be cost-effective.

---

EDIT: I am an idiot who's bad at google. This thread has a picture of the amp mounted, albeit on an Explorer. It's mounted super high, above the glove box, flipped upside-down.

I'll be back after I get everything else squared away.

 

[lowspeedpursuit]

Well, I'm back, but unfortunately the system doesn't work. I think the amp is dead, but I'm curious if anyone has any thoughts:

I tested the controls per the service manual and found that "coast" had intermittent high resistance, so I took the buttons apart and cleaned them and now that's sorted.
I also double-checked all the wiring and had the servo wired up backwards, so I flipped the plug around and now the servo and actuator pass the manual engagement test (+12V on 2, const. GND on 6 and apply ground on 4 to throttle up, remove GND on 6 to throttle down).
I'm also testing with the rear axle jacked up at simulated 35mph, in case there's a minimum speed to engage.

Aside from a bad amp, the only thing I can think of is that maybe I fried the position sensor half of the servo giving it +12V, but it's just a pot. in there, and the resistances check out.
Gonna try to recap the amp starting with the 3 electrolytics, or try and find a new one. Since I have the Ranger/Explorer bracket, my suspicion is I should actually be able to use an amp from a variety of vehicles with different part numbers, which are all actually the same F1VF-14A608-CD board inside.

Thoughts?

 

[RobbieD]

What are you using for the road speed signal? I *believe* that '94 factory cruise systems still used an inline pulse generator on the speedometer cable at the transmission (mine do), and that later models use the ABS sensor on the rear axle, and there's a different PPM (pulses per mile) rate between the two.

 

[lowspeedpursuit]

I'm using the VSS on the transfer case. I grabbed VSS (GY/BK) and VSS GND (PK/O) at the firewall connector and ran them to pins 3 and 2 on the amp's 6-pin connector, respectively. I have continuity all the way from the amp to the VSS, VSS resistance is in spec per shop manual troubleshooting, and presumably my VSS is generating the electric signal properly because it also goes to the ECU, and I've never gotten any codes like 452 "Insufficient input from VSS to PCM".

 

[RobbieD]

I wish I knew for sure if the transfer case VSS signal is the same as the one used inline on the speedo cable, but sorry I don't. If you can score an inline VSS easy and cheap, it may be worth a shot to try it.

 

[RonD]

Yes, its the same sensor, 8,000ppm AC signal

 

[fastpakr]

Somewhere I've got the 94 Mitchell manual with the full troubleshooting sequence. If I can lay my hands on it, I'll post it here.

 

[lowspeedpursuit]

I think we're all talking about the same speed sensor. This guy?

Is there a way to confirm it's generating the electric signal correctly? I do have 3 or 4 of them laying around, so I could always swap to another one.

I have a set of Ranger manuals, and Powertrain/Drivetrain has a pretty extensive section on troublshooting "electronic speed control", but unfortunately anything involving the amp ends in "replace with known good unit", which is pretty difficult at this point.


Per this guy, I know the amp from a '94 Taurus (red box) appears internally identical to the '93/'94 Ranger/Explorer (green box) that I have. Tasca says the '94 Taurus uses E9AZ-9D843-B, which is shared extensively by other stuff like Mustangs, and also still rebuilt as BSE CM3001.

But, I also see other part numbers listed for the Taurus box, and both Tauruses and Mustangs with beige boxes, so I'm not really clear on what the differences are, or what modules might work in my truck.

 

[RobbieD]

Yes, that guy.

You probably also have the Ford EVTM, which says the sensor is "200 to 300" ohms. which I would think would be the static resistance check with a VOM.

The sensor also generates an AC signal, which I would think could be read on a VOM set to AC voltage, sensor plugged in, cruise system powered up, and the sensor spun with a drill (at low speed).

Been way too long since I messed with this stuff; I'm hoping that @RonD will check back in on this.

 

[RonD]

Yes, that's the VSS used from later 1980's thru 1997 in Rangers, 2WD(on trans) or 4x4(on transfer case)

Are you using the the steering wheel buttons, if so the HORN 12v fuse activates the speed amplifier with the ON/OFF buttons on the steering wheel

Look at the two 1994 diagrams and the button slip ring power paths
The 12v passes thru the horn relay to the "cruise on" switch if its toggle to on amplifier gets momentary 12v on its control wire, and turns on
If it gets a full Ground it shuts off, the off button
So does your Horn work?

If using these older models there is no "Cruise On" light, to see if amplifier is even powering up

 

[lowspeedpursuit]

I'm not sure if it's "right", but my VSS generates an AC voltage that increases with speed, up to ~8V @ 45mph. Resistance is in-spec at ~230 ohms.

Horn works as well, and I get +12V on the control wire when I press the "On" button.

 

[RonD]

VSS generates AC volts but the voltage is not what is used

AC voltage is a Sine Wave that goes above 0v and below 0v
Say +8vAC to -8vAC
What is used are these Pulses above 0v, above 0v because one of the VSS wires is grounded
So there is only 1 signal wire needed to the PCM and cruise, because these devices have a Ground already so they just need the + side of the signal

Ford uses 8,000ppm(pulses per mile) as its standard/calibration
Cruise doesn't know MPH, just PPM, so when you set it, it is remembering the pulses at the time you hit the SET button