Hello ProjectSHO89:

OK ran all the diagnostics: Code was 12, so followed the diagnostic procedure per the factory manual. Unplug the antilock control module and check LG wire while holding the brake. Manual says, if voltage is higher than 10 then replace the antilock control module. If not, repair circut 511, LG (light green wire) that goes to brake switch. Voltage was 0.00, which means there is short somewhere in the LG Line. (I already replaced the electronic control module since I bought one).

Qustion is How do I repair the circut 511?

I checked the wiring and the light green wire goes to brake switch which is located behind the hand brake.

Last night I also checked unhooked the wire on tbe brake switch to see if the brake switch was bad but the brake light in the dash stayed on.

I don't know what else to do. Please help. Thanks

 

Can you elaborate on that a little bit more. What orange or red wire did you ground? Did you have to disconnect it and ground, or leave it connected and splice off a ground?

 

this is the wire that is located on the passenger side kick panel. you can disconnect it and then ground it to the body. Then you turn the ignition to ON and count the number of times the ABS light on the dash blinks. It can blink from 2 to 16 times (according to manual).

this is the procedure that is used to determine the ABS code for the 1997 RABS II system rear wheel drive.

 

Several questions:

1) Is the red brake light staying on (continuously) regardless of whether the parking brake is engaged or not? If so, you are troubleshooting the wrong concern. The system is designed so that is there is a fault in the primary braking system that causes the red brake lamp to be illuminated, it forces the RABS system offline along with lighting the yellow ABS lamp.

2) Do your brake lamps work properly?

3) Did you follow the pre-check and vehicle setup instructions in section 206-9A prior to pulling RABS codes?

4) Did you have the parking brake engaged or disengaged when pulling the codes (see vehicle setup)?

5) Have you checked the fluid level and the float switch circuits?

Circuit 511 is the brake lamp circuit. When pressing the pedal, circuit 511 should go to battery voltage, illuminating the 3 stop lamps and also providing battery voltage on the LG wire that serves as a signal to the RABS module to tell it a braking event is occurring.

 

thnaks and I have answer to some of your questions.

1: YES, the light stays ON regardless of handbrake is on off.

2: Yes, all lamps work properly. I will double check after work again.
3: No, I read throught it afterwards and will start there again.

4: I think it was ON when we pulled the codes

5: Yes, I installed the new master cylinder (few months ago when fixing this problem the first time) and double checked its functions. float is fine. fluid level is fine.

I will review the section 206-9A tonight and follow all checkup prcedure again. I will report back to you. Thanks very much.

 

1) Address the red brake light first.
2) Good.
3) Good.
4) See and follow pre-check instructions.
5) Check the float switch CIRCUIT, please... IOW, make sure the switch actually works as intended.

 

Hi: Was just outside going through the procedure:
1: Did system Pre-Check: Setup the vehicle. turn ig off, set parking brake on, then turned on the running lamps. turck is on flat ground so didn't needed to place the blocks behind the tires. Next released the parking brake. Did the following:

RED BRAKE WARNING INDICATOR SELF CHECK: insert the key in teh ig. switch and turn it to START. The warning RED brake light stayed ON even the parking brake was released. The only difference I see is this. When the parking brake is engaged, the RED brake light gets brighter and when released, it gets dimmer. The manual then says: If the red brake light remains ON go to symptoms chart.

REAR BRAKE ANIT-LOCK CONTROL: 2; Red Brake Warning Indicator stays ON whe key is in RUN position: Possible Sources: Ground short on circut 977 (P/W) or on Circut 162 (LO/R) or damaged parking brake switch. GO TO Pinpoint Test B. Test B1: Check Warning Indicator lamps: Disengage the parking brake Turn ignition to #2 position: Both the red brake and yellow ABS ligths are ON (YES) Retreive the codes.

This is where I stopped tonight. Tomorrow evening I will retreive the codes again. In the meantime, I checked all fuses, bulbs diode and everything is working. I am not giving up yet :-)

 

Ok here is what I checked thus far: After the symptoms check, I went with A1: CHECK RED BRAKE WARNING INDICATOR/FUSE.
Following the procedure described on page 206-09a-15. When I released the parking brake the light stays on (also abs lights stays on after self check)
It says GOTO A2. A2 is Check diode resister element and circuit 531. I disconnected the brake fluid level warning switch mounted on the site of the brake reservoir, and using a jumper wire connected it to ground. Red Brake Light does not illuminate. (Red brake light went off as soon as I disconnected the switch. Now it says:; Repair Open in circuits 977 (p/w)531 (DG/Y) or diode resister element. I checked the diode resister element in the power box in the engine compartment and it is OK.
How do I repair the circuits? Please help it is driving me crazy.

 

Did you turn the ignition switch back to RUN for this check? Your results suggest that you missed that step.

I suspect you have a faulty float switch that is stuck in the position that indicates the fluid level is low.

 

Yes I did that. The brake light did not lit up after I turned the ig on even though the manual does not say that

 

Thanks, I think I can check that. There is a procedure in the manual to check for that. I just have to use the meter to check for continuity between the two of the three. I don't know which one but I will consult the manual

thanks for all your help at this point.

What is the likelyhood of wiring gone bad?

 

Actually, the manual does say (in a picture) to set the ignition back to RUN...

Your reported observations, taken in their entirety, are not consistent with both the original fault and an analysis of how the circuit is supposed to work. There has to be an error somewhere in your execution of the diagnostic procedure

If the red brake lamp went out when the float switch was unplugged, there is no other possibility except that the switch has been providing the ground that is triggering the red light.

 

I agree on both your assessments. The manual is a bit odd to read and understand. But I am figuring it out. I have talked to the guys at Advance Auto about the brake Master cylinder and they asked to bring the old one back and they will give me the new one. So that is where I will start.

I want to thank you for all your help and encouragement during this process.

Thank You
msk

 

Here's a quick test to simulate the operation of the float switch:

The switch has a three-conductor harness connector. Unplug the connector and perform the following on the harness connector (not the switch).

Release parking bake, Chock wheels, if needed.
Install a short jumper between the dark green/yellow and the tan/light green wire. This matches the internal switch connection and will simulate a normal brake fluid condition. Now, test the system by turning the ignition to START (red BRAKE lamp should light), then releasing the ignition switch to RUN after the engine starts. The red Brake lamp should go out and the yellow ABS light should go out within several seconds if there are no additional ABS faults.

If that passed, ground that jumper and repeat the test. You should observe the exact same symptoms as brought you here if the switch is stuck or defective.

 

Projectsho89. Ran the test as described. No lights, once the jumper wire was connected. Replacing the master cylinder tomorrow. It is still under warranty. Will post results. I check the continuety between the two connectors on the MC as well and meter shows 0.00 which means there is a short.

Thanks once again and I will post the results tomorrow.