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Discussion Starter #1
My crusise control quit a month or so ago and I am trying to fix it on my own.
I have read that there is a brake sensor switch on the master cylinder that could be the problem. I am getting a P0703 Brake Switch B Input code. Is this the front switch (looks like there are 2 )on the bottom of the master cylinder. Is there fluid behind it ? Do brakes have to be bleed if replaced?
Thanks
 

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My crusise control quit a month or so ago and I am trying to fix it on my own.
I have read that there is a brake sensor switch on the master cylinder that could be the problem. I am getting a P0703 Brake Switch B Input code. Is this the front switch (looks like there are 2 )on the bottom of the master cylinder. Is there fluid behind it ? Do brakes have to be bleed if replaced?
Thanks

Brake switch B is under the hood on the master cylinder. It is the switch at the front end of master cylinder and is the switch that provides power to the ECU for cruise control. Your cruise control does not work if this switch is open. The switch ID number is SW-6349 and the part number is 3L3Z-9F924-AB. Cost about $30 from ford.

The Ford service manual says to remove battery and tray to access the switch. However it is much eaiser to just remove the drivers side wheel inner splash panel. You do not need to remove the tire and wheel. takes 30-40 minutes first time.

Only a few drops of brake fluid will leak and no need to bleed brakes when removing and replacing this switch.
 

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Discussion Starter #4
Thanks to you both for the very clear directions on this issue. I guess I will start with the master cylinder switch. Can I jump the connector plug out to check first to test without messing anything up?
 

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Discussion Starter #5
Well, I replaced the master cylinder mounted switch and still no cruise contol. Anything else I should know before I try the pedal switch?
 

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TimmyaleX
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Well, I replaced the master cylinder mounted switch and still no cruise contol. Anything else I should know before I try the pedal switch?
Do your brake lights work?
 

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Discussion Starter #7
Yes,the cab mounted 3rd light bulb was out but I replaced it a few weeks ago. I cleared the P0703 code and last time I checked it had not come back.
 

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Yes,the cab mounted 3rd light bulb was out but I replaced it a few weeks ago. I cleared the P0703 code and last time I checked it had not come back.

Since you cleared the P0703 code, and the P0703 code has not returned, does your cruise control work?

If not make sure the connector at the switch actually seated and locked. If this is OK then the wiring, either from the brake pressure switch circuit to the PCM or from the steering column cruise control circuit to the PCM could be the causing problem.

The P0703 code is set when the PCM does not detect cruise control power through the brake pressure switch. If you are no longer get the P0703 code then cruise control enable from the streeing wheel/column is most likely. In particular cable chaffing around steering column and firewall area.
 

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Discussion Starter #9
Max,
No cruise control still after clearing the code and I did not get the code again, at least initially. I need to check again and see if has returned. The connector is tight and locked. The pedal switch I am trying to figure out. Is it on the back of the pedal and has a cable (looks like a small single speedo cable as opposed to a wire) running to it? Still have not located the green plastic oval thing with locking pin? I guess I'll try to pull apart the steering column to check for a chaffed wire.
Thanks for the help
 

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TimmyaleX
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Max,
No cruise control still after clearing the code and I did not get the code again, at least initially. I need to check again and see if has returned. The connector is tight and locked. The pedal switch I am trying to figure out. Is it on the back of the pedal and has a cable (looks like a small single speedo cable as opposed to a wire) running to it? Still have not located the green plastic oval thing with locking pin? I guess I'll try to pull apart the steering column to check for a chaffed wire.
Thanks for the help

If your brake lights work your pedal switch works.
 

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Discussion Starter #12
No not yet. I have had no time this weekend.
The next chance I get I guess I"ll try to pull the steering column apart to look for a broken wire.
 

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No not yet. I have had no time this weekend.
The next chance I get I guess I"ll try to pull the steering column apart to look for a broken wire.
In addition to wire problem you need to consider that the cruise control switch assy or the clock spring in the steering column could can cause the problem.

Unless you have wiring diagrams and service manuals may be worth it to ask a local Ford tech what he would charge to hook it up and run a diagnostic check.
 

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I had a problem with my cruise control also. It stopped working and I thought it was a fuse or something but I found out that if you have a problem with the EGR it cuts the cruise control out. I have a spartan tuner so I just put it on a lower tune to let the EGR cycle. That took care of the problem of the cruise control. Ford did that to make you have to take it in to the service dept.
 

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My truck is throwing the P0565 code and my cruise doesn't work.
 

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2009 F350 Diesel

A different poster with the same problem. Intermittently the cruise would shut off. Replaced switch and now it won't turn on, tried another switch, same result. No cruise at all Error code P0703 will not clear.

Maybe wiring harness?????? At least the old switch was intermittent.
 
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