I've got an 04 F150 and I want to replace the brake fluid level switch that is on the bottom side of the master cylinder, but I'm not 100% sure how to remove it. I don't want to start yanking on it and end up breaking it. I already unplugged the wire harness going to it, but I could not clearly see how to release the old switch.

Does anyone know how to remove it? The new one looks like it just pushes in and snaps in place once it is pushed in, but I don't know how to release the old switch in order to remove it since the switch is under the master cylinder and at such an angle that I can not see under there very easily.

 

is your 2004 the new body style or heritage?

You say "Brake Fluid Level Switch" but then you also say "on the bottom side of the master cylinder" so you have me confused...

The FLI ("Brake Fluid Level Switch") is in the reservoir, not under the master cylinder. The master cylinder is the aluminum thing that the reservoir sits on. So technically the FLI is above the master cylinder.

Older models had a cruise switch "on the bottom side of the master cylinder" but not the 2004 and up versions. This is a pressure switch that detects pressure in the master cylinder to deactivate the cruise control.
I'm not sure if they had this on the 2004 heritage version though.

Assuming that you do mean the FLI - on the opposite side from the wiring connector you should see the FLI end. It has 2 "fingers" that grip the reservoir. You need to use a small needle-nose pliers to squeeze these fingers while pulling on the wiring connector side of the FLI (maybe use pliers to pull on that side too).

This could be a little tricky when its in the vehicle... it may take 2 people - one to look at & squeeze the fingers and one to pull.

When you install the new one - push it in all the way, and then give a tug on it to make sure the fingers snapped into place. Or look at the fingers to visually confirm this.

It might be easier to see what I'm talking about if you use a small mirror to get a good look at the tip of the FLI.


If you can't make this work, there is another option... but its riskier. You can just grab the FLI wiring connector with a pair of pliers and pull real hard. Usually the fingers on the FLI fail first BUT sometimes you will damage the reservoir. So I would only do this as a last resort.

 

Yes it is the newer body style, not heritage.

Correct I meant the reservoir.


I will look on the opposite side of the reservoir for the prongs tonight.

Thanks for the help.

 

I got home tonight and I felt the prongs of the switch poking through the opposite side of the reservoir like you said. I could not get my needle nose pliers in there, but I was able to push the prongs in some with my fingers and wiggle the switch out. Thanks again for the help. Sometimes it's hard to know how to remove things when you can not see the thing.

Thanks

 

glad it worked!

 

Yep, unfortunately my brake light is still on intermittently. So I don't know if maybe it is a corroded connection somewhere or what. I need to dig into it a little further to try and find out.

 

I know this is an old thread, but I just had to do this on my 04 f150. The information here was very useful, but I was getting pretty frustraited trying to get pliers onto the squeeze tabs and was just about ready to rip the thing out when I saw a better way.....

If you take out the two bolts holding the coolant overflow tank in and lift the tank out of the way (leaving the hoses and connectors on it) it's easy to get to the backside of the level switch to release the tabs.

Doug