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I had a question regarding wiring on the handbrake. There is only 1 wire to the handbrake a light green wire. It looks like when the handbrake is engaged it is grounded when it's disengaged it's open. Is this wire supposed to receive voltage somewhere? The reason I ask is that I my turbo timer no longer shuts off when I disengage the handbrake. The last thing I did was install a new radio. I'm guessing there is a wire there somewhere that I screwed up. I tried searching and can't find anything. Any help would be greatly appreciated.
Did more testing. It looks like the issue is that I'm not using the OEM instrument cluster. Once I plugged it back in the TT start working again.Now to figure out why that is.
So looking at the FSM. Can someone help me decipher what I need to do? It looks like it's going into the cluster with BR/Y. Is it supposed to connect to 4L to complete the circuit when the handbrake is engaged?
I believe that wire just needs to short to ground for the turbo timer to work. If that's all you are wanting to do, just make sure the wire grounds out when the parking brake is down.
That said, looking at the diagram the wire goes to 4J on the cluster. The brake fluid level sensor also goes there. It's powered by 4L. 12v power goes into 4L, there is a bulb, then there are the 2 potential grounds that can turn the light on. If either one go to ground, the Brake light comes on.
The turbo timer is simply looking for a ground - you should be able to test it by touching that wire to ground as the TT is running. I think you can just bypass the whole system just by hooking the wire to ground. It's just a measure to make sure you don't try and drive the car when the TT is running, as soon as you drop the parking brake it turns off the engine.
The BRAKE Light is connected to Pin 4J (not 4L as you noted) on the instrument cluster and goes through Connector C1-01. From Connector C1-01 the wire color is Brown/Yellow (BR/Y) then connects to Connector X-06. From a tie point, the signal path to ground flows through Connector C1-11 at the Master Brake Cylinder (Brake Fluid Level Sensor). When the brake fluid drops below a specific level, the BRAKE light will come on. The second path to ground flows through Connector X-06 to Connector C1-10. This wire is Light Green (LG). The Parking Brake Switch is drawn in its static state, "normally open" or "NO". When the switch is NO that means the brake leaver is in the down position, or is off. This means the parking brake function of the rear calipers is not engaged. When the brake leaver is in the up position that physically pulls on the parking brake cables and clamps down the brake pads on the rear brake calipers. Electrically, when the brake leaver is pulled up, brake switch is closed. A path for ground now exists and illuminates the BRAKE light in the instrument cluster.
The reason why the Turbo Timer is connected to the parking brake switch is a means of anti-theft. When the brake switch is closed, it would allow the timer to count down. Hence the driver could remove the key, lock the car, then go about his business. If the brake switch is opened during the timer count down, that removes a ground signal to the timer and immediately cuts the ignition.
Does that answer your question?
I have a few for you:
1. What did you mean by not using the OEM instrument cluster?
2. And what did you plug back in?
3. Are you using an aftermarket gauge setup?
4. Wouldn't the above be important to mention in your initial request?
Thanks for the clarification Dale and George. Sorry for not being more descriptive. I'm no longer running the stock instrument cluster. I installed a AEM CD-7, stand alone cluster. It plugs directly into CAN Bus so I'm not using any of the plugs from the original cluster. I plugged back in the stock cluster and TT is working again.
So if I'm understanding you properly, I'm missing a connection from X-06 to C1-10, the LG wire? So if I connect the two pins, 4L and 4J, that would complete the circuit when the braking brake is up, grounded state?
You're welcome. Thanks for the clarification. I don't know how the CD-7 cluster is configured in your car. I recommend that you refer to both the FD schematic and the CD-7 schematic to get the big picture of gauge & signal integration.
From a purely stock perspective, Pin 4L gives some sort of logic circuit for a lamp test when the car is switched on for 30sec. Don't quote me on that though. Where you see "4L" on the schematic, that is not a tie point. Otherwise you would see a dot. The top side of the BRAKE light is a good example of a connection dot. Therefore, the positive side (top) of the BRAKE light gets its power from the METER fuse via Connector C1-01, Pin 2D. You have to follow the line to the left of the BRAKE light. It is labeled "A" and continues along Diagram C-1a.
I do not know what connections you are missing unless you take resistance measurements on your instrument cluster. Again, refer to the CD-7 schematic for integration into your car. That may help your situation. Unless the radio is a red herring, did you splice into the car's wiring harness or did you use a connector kit between the aftermarket radio and wiring harness? If you spliced into the harness then please list those spliced wires from their respective connectors.
What are you trying to fix - to use the Turbo Timer, to have a functioning brake warning light, or both?
Track back the schematic from Pin 2D. The +12V signal originates from the battery (alt is in parallel to charge it once car is running), flows through MAIN fuse (120A) then to B1 fuse (40A) to the Ignition Switch at Connector X-03 via B/G wire. Once the ignition switch is placed to the ON (IG2) position, a tie point connects it to the IG1 position. The signal continues to flow through the METER fuse then branches off through Connector X-18 and then to Connector C1-01, Pin 2D.
If you are only concerned with the Turbo Timer power as it is currently connected to the car then you could run a wire from C1-01 Pin 2D to Connector C1-01 Pin 4J. This will bypass the BRAKE light circuit all together. The Parking Brake Switch will still function as a kill switch for the turbo timer when the Parking Brake Leaver is placed in the down position.
I really like it. It's a direct plug and play through CAN Bus to my AEM EMS-4. There is some software setup involved, but it isn't too bad. The one cumbersome thing to do on it is getting it to read fuel level. To do that I need to dump all my fuel and fill up the tank one gallon at a time and see the voltage readings are since it's non linear. They just recently release a newer dash design software too, which you can create more appealing gauge faces. I have yet to play with it though.
Thanks for sharing a pic. You may be able to make a custom connector between C1-01 Pin 2D and Pin 4J. This would keep your instrument wire harness unmolested but still add your TT to the park brake switch. You could also revert back to the OEM cluster without any worries.
01-06-18, 06:40 PM
Handbrake Wiring Question
