I have scoured the forums and tried to figure this out. Let me start with, I have a 94 f150 with the 302 and 5 speed tranny. My problem is the brake light not abs light will not go out. The light will be bright with the e brake on (i have a manual). When the e brake is released it will go dim. I started with the brake switch for the emergancy brake. I removed the switch and activated it by hand with a jumper wire to ground. It worked as described above. After some forum searching I found out about the brake fluid resivior sensor. When I disconnect it the light goes out completely and functions normal with the e brake. I looked further into that and found a badly corroded terminal in the connector. I replaced the connector and sensor. Back to the faulty operation with the dim light (e brake off) bright light (e brake on). I cannot find a wiring diagram with the brake system in it. I have a Chiltons manual for the truck. I am asking if anyone has had this problem before. I do not know where to go from here or what to troubleshoot without a wiring diagram. If anyone has any solutions to this or if they have a wiring diagram please let me know. Seeing that brake light on constantly is annoying.

 

First off - you are talking about the brake light on the dash, right?

so when you unplug the Fluid Level Indicator (FLI) in the reservoir the brake light goes out?

Have you confirmed that your brake fluid reservoir is full? If it is too low it will turn the light on (thats the point of having a FLI)

Are you sure you replaced it with the correct FLI?
Are you sure you wired the new connector properly?

The older Ford FLIs had 3 pins. There was a resistor in them that allows the truck to know if the FLI is hooked up.

I think the newer Ford FLIs might still have 3 pins, but 1 isn't used.

My working theory (just a guess here) is that maybe the FLI went bad (or the corroded pin caused a short) and that turned the light on. Now you replaced it and its either hooked up wrong, the wrong FLI, or somehow you got a bad FLI.

hopefully that helps.

 

I am talking about the dash brake light. I replaced the fluid with dot 3 brake fluid. I used four different sensors and still continue to have the light with them all. I tested two of the sensors on a friends 94 and they work. I rewired the connector with one from a 94 and there was no resistor in it. It is three wires. I dont remember the exact colors but they are in the correct order.

 

the resistors are inside the FLI so you won't see them.

Sounds like you did a good job making sure it is not the FLI.

My next guess would be you have a short somewhere in the wiring. Its probably a "bad short" so you aren't making good contact, hence the dim light.

As for why it disappears when you unhook the FLI - maybe the short is on the wiring feeding back from the FLI so you only see it when the FLI is hooked up and completing the circuit?

These are just educated guess on my part.

Might be simpler to just put a piece of black tape over the light!

 

The problem with that is I have a manual. I like knowing if it is on or not.

I am an electrician. If I can get a wiring diagram I can troubleshoot all the wires. Repairing a shorted wire is not a problem for me. I just need to know what pins to test.

 

Update, the abs light is on as well. I didnt know it but the bulb was burned out.

 

Time to take it to Ford and pay for the diagnostics, unless you can find a code scanner that can read ABS codes.

 

I learned how to read the codes. I found this page that many people could probably use.
http://www.supermotors.net/registry/media/280857

 

Yep, that's exactly what you need. My last response was thinking a newer truck with 4 wheel ABS and OBD-II.

 

Oh nope I have an older one. Other than this abs light and some body work she is in good shape. If I didnt need it so bad I could flip it an make a couple grand on her. Im going to keep her though.