Join Date: Jan 2010
Location: Fountain Valley California
The W/D shows an reads that the brake fluid level sensor is a 2 position switch (either open or closed contacts). A normal system would see that switch in an open condition at all times. If the Instrument Panel Cluster see's that the switch contacts are closed, it will turn on the red brake light in a steady state. So technically, when the low level sensor/switch connector is disconnected, it should create the same condition as telling the IPC, that the master cylinder reservoir fluid level is good (switch contacts in an open condition). Having a faulty/intermittent ground actually would assist in *preventing* the red light from coming on (very confusing). If the power wire arriving at the connector had developed a constant or intermittent short to ground, that would cause either a steady or intermittent brake light condition. Even the circuit test procedure (in the service manual) is backwards from the W/D itself. In itself, that would not make any difference to a open/closed switch. If you have a meter, check for 5 volts DC +/- a little from either pin to a good ground source. If OK, the remaining pin must have a next to zero resistance reading to a ground source. If the power wire has developed an intermittent short to ground condition, you (or somebody) might be in for a somewhat long an painful T/S session trying to zero in on it.
Added info>>>>> Reading another section in the service manual, is counter to the above statement on switch position. This is the information from that section of the service manual titled "Brake Warning Indicator Malfunction", It says that the switch is normally closed (when the fluid level is correct). That makes the fix by "EMax" seem more probable. This darn service manual is so screwed up. The ground return wire from the low level switch is joined with at least 10 or 12 other wires going to the same grounding location. It is located on the inside right frame rail approximately below the fuse an ECM modules. Think you need to gain access to that grounding location an carefully check out the condition of the grouped together wires. Its overall condition may affect one or more things attached at that location, or that particular wire is breaking down (as in open at times an connected at times).
Last edited by GOPHERIT; 05-06-2019 at 04:53 PM.
Reason: added info