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Rostra Cruise Install on a 1990 Ranger?

plaligraphy

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How bad is the install process for the rostra kit? (Link to Rostra Kit)

It looks decently simple but I'm not the best with electrical work

Thank you!
 


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85_Ranger4x4

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It takes a little wiring but the factory system is fairly standalone if you can find a donor. I added it to my truck.
 

RobbieD

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The wiring connections wouldn't be that bad. Mounting the components, especially the control head, and routing the wiring will be more of a hassle. It looks like that kit uses magnets on the driveshaft and a pickup for the speed signal, so be prepared for that. The throttle connection can be finicky, it's usually mostly "fabricated", and has to be made with care. It's a "universal" kit; with care, it'll probably install and work acceptably.

I would prefer a vacuum servo design over the electronic servo, but maybe these work better now, as compared to when I installed these things. And I really agree with @85_Ranger4x4 , that in this case the factory system is much better than anything aftermarket. Sorry to be a party pooper, but I'm being straight-up on the subject.
 

franklin2

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When did Ford start using a speed sensor in the driveline? I don't think my 86 had one, but I know they started using them at some date, and that would be the wire to intercept for the aftermarket speed control.

I believe the early trucks used the same system they had been using since the 70's, with a short speedo cable from the trans, a speed generating device on the end of the short speedo cable, and then another short speedo cable going into the firewall to drive the speedo. The one car I have seen with this system had the speedo generator sitting down near the steering column area under the hood.

If you could find a factory setup, I bet it would not be that hard to install if you had the donor there. It would have all the brackets, switches, etc to install it, after all it was a option on most broncos and rangers.
 

RobbieD

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I believe the early trucks used the same system they had been using since the 70's, with a short speedo cable from the trans, a speed generating device on the end of the short speedo cable, and then another short speedo cable going into the firewall to drive the speedo. The one car I have seen with this system had the speedo generator sitting down near the steering column area under the hood.
Yes, it's inline on the speedo cable, on the trucks that had cruise control.
 

85_Ranger4x4

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It isn't a super easy thing but to me it wasn't too bad. From what I remember the main power plugs into the back of the fuse panel. You need the harness that runs between the servo and the amplifier (module) and the harness that goes to the steering wheel and of course the horn pad with buttons. You need to run wires down to a speed sensor on the trans/t-case and tap into the brake signal on the outside of the firewall. Install a vacuum switch on the pedals. And run all the vacuum lines (plain tubing)

Servo bracket and vacuum switch bracket are the hardest to acquire. One is riveted in and one is buried in the dash on top the pedal bracket.

A taste of what needs done:





If you go this route and need any help let me know. I have a lot of diagrams, connector pinouts and troubleshooting stuff and my truck is sitting in the garage if you need pics.

The Rosta is mentioned here:


I have never been around it, @Ranger SVO was just on here a couple days ago, maybe he has more input on it.
 
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plaligraphy

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Thank you! My local junkyard has a wack ton of 2nd gen Rangers. Is there a part list somewhere of what I would need to do the factory conversion?
 

85_Ranger4x4

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Uh, kinda got in trouble here, on my phone I thought your truck looked like a first gen...
 

franklin2

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Thank you! My local junkyard has a wack ton of 2nd gen Rangers. Is there a part list somewhere of what I would need to do the factory conversion?
On a project like this, you really need to wrap your head around how the system works and all it's little nuiances and little pieces and what they do. Then it's no problem going and getting what you need, you know exactly what you need. And then when you put it in and it doesn't work for some reason, you are on top of it and can troubleshoot it.

1st thing to do is get a diagram like the previous post for your year truck. If you are having problems understanding it, post it up and we can talk about it. Apparently the diagram above is not for your year truck? Or will it work?
 

85_Ranger4x4

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On a project like this, you really need to wrap your head around how the system works and all it's little nuiances and little pieces and what they do. Then it's no problem going and getting what you need, you know exactly what you need. And then when you put it in and it doesn't work for some reason, you are on top of it and can troubleshoot it.

1st thing to do is get a diagram like the previous post for your year truck. If you are having problems understanding it, post it up and we can talk about it. Apparently the diagram above is not for your year truck? Or will it work?
The newer you get the more integrated things kit. Mine works with no engine input from a powertrain computer so it might work if the 2nd gen steering wheel switches work the same. I know the applifier looks very different between the two systems.

I would try to go with the 2nd gen system if anything though. Did @BlackBII do this to his Ranger? For some reason I got thinking this morning he did...
 

BlackBII

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I sure did. Wasn't bad at all, just needed to add all the factory stuff.

You need
Steering wheel cover with buttons
Clock spring (slip ring contacts)
Harnesses
Vacuum module and bracket
Amplifier
Horn relay







http://www.thorssell.net/hbook/ccexpl.html

Ford Cruise Control - How it works
Amplifier

The Amplifier (Amp) is the "brains" of the system. It simply senses road speed from the Vehicle Speed Sensor (VSS) and opens and closes the throttle to try and maintain that road speed.

Servo
The Servo contains a large diaphragm along with two solenoids and a feedback potentiometer. The diaphragm is attached by a cable to the carburetor or throttle body linkage. Engine vacuum is supplied to the Servo through a vacuum check valve which only allows vacuum to go one way.
The two solenoids are for Vacuum and Vent. One side of each solenoid is connected to battery positive with the key on. To activate a solenoid, the Amp grounds out the other side of it.

When the Amp wants to open the throttle, it activates the Vent solenoid which blocks it off. It then pulses the ground on the Vacuum solenoid to apply vacuum to the diaphragm. The diaphragm pulls the throttle open a little more each time the Vacuum solenoid is pulsed.

The Amp keeps activating the Vacuum solenoid until the desired throttle opening is reached. The Amp also uses the feedback potentiometer to determine how much the throttle is moving and bases its adjustments on that.

Even if the Vacuum solenoid stops applying vacuum, the diaphragm will hold its position. It won't release the vacuum until the vent solenoid ground is released. Then the vacuum gets dumped to the atmosphere.

If the Amp just wants to let the throttle go a small amount (going too fast for example) it will momentarily ground the Vent solenoid to dump a small amount of vacuum.


Vehicle Speed Sensor
The VSS is connected to the speedometer cable. Most of the later models had the speedo cable plugged INTO the speed sensor. On this type, the gear on the end of the sensor is driven by the output shaft in the transmission, and the sensor in turn drives the speedo cable.

The sensor acts as a little generator. A magnet spins in a coil of wire to generate an AC voltage.


Switches
The system switches are built into the steering wheel cover. Later models have ON\OFF, SET\ACCELL, COAST, and RESUME buttons. Some of the earlier systems did not have the RESUME.
The switches have a ground circuit and also get 12 volts through the coil of the horn relay. By the way, unlike most other brands, Fords during the years that this cruise was used only had a horn relay if they had cruise. We used to get calls all the time from people looking for the horn relay on non-cruise equipped cars.

One wire goes from the switches to the Amp. I'll refer to it as the "switches" wire in this explanation.

Here's how the switches operate:
The ON button when pressed puts positive (about 12 volts) to the "switches" line.
The OFF button when pressed grounds out the "switches" line.
For the other functions, the buttons switch a resistor between ground and the "switches" line. The Amp senses the different resistances and performs the necessary function.

Other Parts
Brake Light Switch

The Amp has a wire coming from the brake lights. It senses the brake light voltage when the operator steps on the brakes and disengages the cruise control.

Note: The Amp is also set to look for a resistance to ground through the brake light bulbs. As a safety feature, if it doesn't see this ground, it won't operate because it thinks the wire to the brake light switch may be broken.

Bottom line is that if both brake light bulbs are burned out, the cruise won't work. I've seen it happen a few times.

Clutch Switch

Vehicles with manual transmissions also have a switch that opens when the clutch is pushed in. This keeps the engine from revving up.

The clutch switch is wired in with the brake light switch so that it breaks the circuit to the brake light bulbs. Due to the safety feature mentioned with the brake lights above, the systems disengages.

Vacuum Dump Valve

Later systems have a vacuum dump valve on the brake pedal. A vacuum line is connected from the valve to the Servo diaphragm. When the brake pedal is pushed, vacuum in the Servo is released (dumped).

This is another safety feature. In the earlier models without this valve, when the brake light switch went bad and you were using the cruise, the more you tried to stop the car the more the Amp tried to accelerate.
 
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RobbieD

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Great description! Thanks.

Brake Light Switch
The Amp has a wire coming from the brake lights. It senses the brake light voltage when the operator steps on the brakes and disengages the cruise control.

Note: The Amp is also set to look for a resistance to ground through the brake light bulbs. As a safety feature, if it doesn't see this ground, it won't operate because it thinks the wire to the brake light switch may be broken.

Bottom line is that if both brake light bulbs are burned out, the cruise won't work. I've seen it happen a few times.
And that's also why changing your tail lights to (unloaded) LEDs will kill the cruise control- they don't have the resistance that the incandescent bulbs have.
 

franklin2

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On the dump valve, it has a specific purpose. If you don't have it, and you hit the brake pedal, it's like hitting the off switch on the steering wheel. The cruise just gently releases control of the throttle. I retro fitted one of these systems on a old truck I had, and found this out.

With the dump valve connected, it has a very large opening in the pedal valve, and a decent sized hose running from the vacuum servo to the valve. When you hit the pedal, the electrical part tells the cruise to release, but the dump valve "dumps" the vacuum off the servo very quickly. So if you are in cruise and slam on the brakes, the cruise is instantly out of the picture when the dump valve dumps all the vacuum from the servo.
 

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