Cruise control not working, can’t figure out what is wrong

[mdiiorio]

Hello,
Sorry if this is lengthy but I want to share all the events to not waste anyone’s time on responses. I am by no means a mechanic and am actually pretty new to working on cars, so if I say anything seemingly dumb I’m sorry...

I have a 2004 Ranger FX4 manual trans. So my cruise control quit working and I went to have it diagnosed. Mechanic said the module/servo was bad and quoted me 700 bucks, needless to say I passed on it. I then ordered a used servo for 65 on eBay and put it in, still nothing. Fuse looks ok, and I would imagine that was the first thing the mechanic checked when diagnosing. When I did the diagnostic sequence I got 2 flashes. Tried a new brake light switch, still not the problem. Didn’t want to mess around with clutch switch if I’m not sure that’s the problem, and it seems to be working fine. Just to make sure that the servo I ordered worked I met up with my friend who has a 2004 FX4 with cruise control that works and swapped them. His servo did not work in my car and mine worked in his, so the servo I bought is good, there is obviously another problem. Now that I have a good servo in it, what else could be the problem, and could that problem have to do with my first servo going bad?

 

[RobbieD]

Welcome. Do you have stock tail light bulbs? I don't know about the newer trucks, but changing out incandescent (old school) brake light bulbs for LED bulbs can kill the cruise control in older trucks. The cruise control needs to "see" ground through the unlit bulb filaments in order to operate. I'm assuming that your 2 flash code led you to changing the brake light switch?

 

[mdiiorio]

Welcome. Do you have stock tail light bulbs? I don't know about the newer trucks, but changing out incandescent (old school) brake light bulbs for LED bulbs can kill the cruise control in older trucks. The cruise control needs to "see" ground through the unlit bulb filaments in order to operate. I'm assuming that your 2 flash code led you to changing the brake light switch?

Welcome. Do you have stock tail light bulbs? I don't know about the newer trucks, but changing out incandescent (old school) brake light bulbs for LED bulbs can kill the cruise control in older trucks. The cruise control needs to "see" ground through the unlit bulb filaments in order to operate. I'm assuming that your 2 flash code led you to changing the brake light switch?

Yes I have stock brake light bulbs. I did change them a while back because one was out but they were just standard bulbs and I remember my cruise still worked after that I changed them. And yes the two flashes got me to change the brake light switch but that didn’t fix it. I definitely don’t want to keep buying and returning parts because that can get very time consuming and pointless, which is why I haven’t done the clutch pedal switch. I personally think there is problem in the circuit that somehow killed my first servo, but I’m no expert lol

 

[Curious Hound]

Since new servo didn’t work, your original might actually still be good. If you know which wires it is on the clutch switch, you could probably just short them together as a test.

 

[Dirtman]

Might I suggest this brick?

 

[RonD]

Yes, Welcome to TRS

This is the de-activator for cruise in 2005 Ranger don't have the 2004 diagram, but most likely the same

There is a separate Pressure switch on the brake line, normally closed, it pass 12v to cruise when key is on, you could test it with OHM meter, 0 ohms means its closed
And fuse 26 in cab needs to be OK

Brake pedal switch has two switches inside, the brake lights of course, and then a second switch that acts as a "sensor"
When brake pedal is up this sensor is a GROUND which passes thru the Clutch switch and to the cruise module
So ground means cruise can turn on
No ground = no cruise, it means brake switch is broken or disconnected, like if clutch pedal was pushed down, no ground
This wire is 12v when brake pedal is pushed, but the lack of a Ground on this wire is what would shut off the cruise
Its a "fail safe" circuit

So test connector on cruise module, pin 9 should be 12v key on
Pin 4 a ground if clutch and brake pedal are both up