1997 F53 Cruise Control Brake Pressure Switch Wiring

[S_King]

Got a 97 F53 and I’m working on my cruise control system. I’m testing for power going to my brake pressure sensor. (At least I think that’s what it’s called) located on my master cylinder. There is no power to it and I’ve been looking all over for a diagram to let me know if there is supposed to be power to it and if so when? Example: while pressing the brakes or when cruise control switches on or when power to ignition switch is on or when vehicle is running? Any help would be greatly appreciated. Thank you in advance.

 

[TheBar]

For an RV that old you really need a repair and wiring manual. Even professional mechanics may need a manual to fix problems. There seems to be one for sale here.

But, I would expect the switch you are looking at is a negative (ground) switch not positive power. With a test light you can find out if it grounds when the brakes are applied.

Why are you asking? No brake lights?

 

[S_King]

no cruise control. Brake lights are good

 

[John From Detroit]

Interesting I've not seen a brake pressure type switch as the brake lights or CC shut off sensor in a long, LONG time (High school and it was an older car then)
Most use a switch that detects the brake pedal arm now days.. Much more reliable.

I suspect that "Switch" is something else entirely.
That said.. Some aux-brake systems for towed vehicles (IE: Trailer brake controller) might.

Also there is a "Brake system failure" sensor. this is a switch that detects an imbalance in dual brake systems used in modern (They started using those in the 60s or 70s as I recall) so if half your brakes loose pressure (Blown cylinder/caliper or line) you get a FAULT light. Might be that one.
only power when engine on

 

[S_King]

For an RV that old you really need a repair and wiring manual. Even professional mechanics may need a manual to fix problems. There seems to be one for sale here.

But, I would expect the switch you are looking at is a negative (ground) switch not positive power. With a test light you can find out if it grounds when the brakes are applied.

Why are you asking? No brake lights?

Thank you I just ordered mines

 

[TheBar]

If you have brake lights your cruise control problem is likely not related to the brakes. That may be a brake fluid level sensor. My 97 Ford master cylinder has one.

You've checked all the fuses? Cruise control systems can be complicated. But likely use the same components used on pickup trucks, etc.

 

[Kirk]

On a 1997 Ford F53 motorhome chassis, the cruise control deactivation brake pressure switch is typically located directly on the brake master cylinder, often near the front end. This switch is part of a critical safety recall (09S09) due to risks of leaking brake fluid leading to fire. For safety, check your VIN at the Ford Recall site to see if this switch has been addressed. The switch is designed to have hot 12-volt power at all times. It is a normally closed (NC) switch that sends a signal to the cruise control system. When the brakes are pressed, the pressure acts on the switch, opening the circuit and disengaging the cruise control. Since it is a normally closed switch, you will need to measure voltage between the connection and ground to know if it is there. I used to have a 1998 F53 and had the recall done and it was the addition of a fuse in the 12V supply but I do not remember where the 12V came from. If you trace the harness to that switch back you should be able to locate the fuse which was added.

 

[S_King]

On a 1997 Ford F53 motorhome chassis, the cruise control deactivation brake pressure switch is typically located directly on the brake master cylinder, often near the front end. This switch is part of a critical safety recall (09S09) due to risks of leaking brake fluid leading to fire. For safety, check your VIN at the Ford Recall site to see if this switch has been addressed. The switch is designed to have hot 12-volt power at all times. It is a normally closed (NC) switch that sends a signal to the cruise control system. When the brakes are pressed, the pressure acts on the switch, opening the circuit and disengaging the cruise control. Since it is a normally closed switch, you will need to measure voltage between the connection and ground to know if it is there. I used to have a 1998 F53 and had the recall done and it was the addition of a fuse in the 12V supply but I do not remember where the 12V came from. If you trace the harness to that switch back you should be able to locate the fuse which was added.

Ok I will check that this weekend and also that’s what I was trying to find out if it supposed to have voltage there. I check the two wires going to the connection and it’s neither voltage or ground. As far as the recall yes it was done already. I ordered a service manual to help figure out where my power and ground sources are and go from there. Also in a different post I disconnected my main connector between the mobile and chassis and it was corrosion on it. I cleaned it up pretty good but based on the pictures, someone told me I had some broken pins which leads me to believe I’m not getting power or ground to the circuit I need. One of them was my horn. I traced the wire from one side to the other side and that’s where I lost power at. Once I’ve mended the connection my horn works perfectly. I’m wondering if the same issue is going on with Power going to PARTS of my cruise control system.

 

[Kirk]

I’m wondering if the same issue is going on with Power going to PARTS of my cruise control system.

If there is no 12V as measured from either side of the switch to chassis ground, the cruise control will not engage. You could also check the switch with a meter as it should be closed when no brake is applied and then open when the brake is pressed.

 

[Lou Schneider]

no cruise control. Brake lights are good

Did you replace the brake light bulbs with LEDs? The cruise control needs to see continuity to ground through an incandescent bulb filament to engage, LED bulbs don't provide that.

 

[House Husband]

The Ford recall wiring harness has a fuse in it.
Also, what LO posted about the tail lights will also affect the torque converter lock up.
I made the LED mistake and added a small incandescent lamp to each side for the necessary ground.

Richard

 

[Lou Schneider]

The Ford recall wiring harness has a fuse in it.
Also, what LO posted about the tail lights will also affect the torque converter lock up.
I made the LED mistake and added a small incandescent lamp to each side for the necessary ground.

Richard

You can also buy small resistors that go in parallel with the LED bulbs that do the same thing.

 

[bigbAZ]

On a 1997 Ford F53 motorhome chassis, the cruise control deactivation brake pressure switch is typically located directly on the brake master cylinder, often near the front end. This switch is part of a critical safety recall (09S09) due to risks of leaking brake fluid leading to fire. For safety, check your VIN at the Ford Recall site to see if this switch has been addressed. The switch is designed to have hot 12-volt power at all times. It is a normally closed (NC) switch that sends a signal to the cruise control system. When the brakes are pressed, the pressure acts on the switch, opening the circuit and disengaging the cruise control. Since it is a normally closed switch, you will need to measure voltage between the connection and ground to know if it is there. I used to have a 1998 F53 and had the recall done and it was the addition of a fuse in the 12V supply but I do not remember where the 12V came from. If you trace the harness to that switch back you should be able to locate the fuse which was added.

The recall consisted of a fusible link inserted into the supply wire to the switch (if it wasn't already leaking). The fusible link had a blue label on it and from the OPs picture it looks like the fusible link is installed. (I got one on my Superduty)