2005 Ford F150 brake warning light turns on and off while driving

It is the red brake light and I tried pulling up on the parking brake and that does not turn the light off.

While light is on, unplug fluid level sensor at the master cylinder reservoir, it may be failing.. It is replaceable!

I will try that. I was thinking that it might be going bad. So the sensor is replaceable?

Available from other sources, I just have quick access to the NAPA site.. This is @ full list price: Brake Master Cylinder Fluid Level Sensor $ 32.49 /ea Part Number: FLS663 Product Line: NAPA Echlin Ignition Parts

Thanks for the information. So I understand, when the light comes on unplug the sensor the light should go off this will mean the sensor is bad.

You got it!!

I tried unplugging the sensor at the master cylinder and the light stays on. Any other suggestions.

Scan test ABS.. The red light is also related!.. This requires a professional scanner, not a code reader.

Ok that was my next thing to try. I do have a scanner that scans the ABS.

Post the codes.

I used my scanner to check the ABS. No ABS DTCs are presently stored in tool's memory.

Most people don't have a true scanner... Does it have an actual ABS segment?.. Can you read ABS **live data** on your..scan tool??

It does have a ABS segment.

Leave it hooked up and have helper watch the ABS live data screen while driving to see what's happening when light comes on.

ok will try that. This light is driving me crazy. I can not run a live test with my scan. However I was able to run a KOEO and KOER Test. Both of which came up with a code P1703 Brake Switch Out of Self Test Range. Don't know what the code means.