mike9186

Over the past few days, while driving, the "HANDBRAKE!" warning light has been appearing in the instrument cluster. It will sometimes flash on and off within a second and other times it will stay on for a minute or two. Its also seems sensitive to road conditions so it will flash on after going over a bump. Also my handbrake in the 'off' position is very loose and is only laying flat because of gravity. It will jostle up and down a bit if going over a bumpy surface.

This definitely seems like an electrical issue and not a physical issue with the brake shoes. It has been extremely hot and humid on Long Island lately so maybe there is a connection....

I've done some searching and maybe some people with Cayennes have had a similar issue in the past but can't find anything 997 related.

Any help would be much appreciated!!!!

-Mike B

lowbee

Check your brake fluid

mike9186

Interesting. I am due for a brake fluid flush (both based on time and from the test strip I used in the spring...It was light pink and in the early stages of oldness).

I'm not exactly sure what this has to do with the parking brake which doesn't uses a cable to actuate but I've seen stranger things happen!

lowbee

In most car that parking brake light will flash when brake fluid drop below the minimum mark, so when u hit a bump it triggers the sensor to tell u your brake fuild is low

mike9186

Brake fluid is filled to the top. I suspect the issue is a failed switch. It is this part:

http://www.paragon-products.com/Pors...613.112.01.htm

Has anyone replaced this switch? Does it require disassembling the entire center console? I hope not but I suspect the answer is yes.

mike9186

The switch was the problem! No more warning light!

mike9186

Update: Warning light is back.

Previously the warning light would flash on and off intermittently with a little 'ding' sound. Sometimes it would do it constantly, other times once or twice in an hour drive.

Now the brake light is constantly illuminated (the word 'brake' in the instrument cluster) and the big red brake warning light is solid on the bottom of the tachometer.

I'm not sure what to do. Is it a fuse? If so which one? I just unplugged the battery to see if that clears anything. The brake fluid is completely topped up so I am certain it isn't that.

motopix

Sorry, I have no input but thank you for following up...

ru'

Pad wear indicator? Or maybe the wire from one has broken and is shorting on the metalwork somewhere? tbh I do not know exactly how these cars indicate pad wear, so I may be utterly wrong.

semicycler

Not positive but this is the first thing that came to mind too. Check your brake pads for wear. You could be due for new pads, maybe rotors too.

Rocco07

When the pad wear sensor located at each inboard brake pad touches the rotor, the electrical circuit is affected resulting in a warning light.
If this is the case, the sensor will need to be replaced along with pad replacement. IIRC the sensors are about $25 each.
Some people periodically check pad wear to avoid the fault indicator and save the sensors. I've seen the sensors 'tied back" away from the pads to avoid their destruction. But this means the pads must be again periodically checked to avoid rotor damage by worn pads because the indicator will not illuminate.

mike9186

Hi guys, thanks for the help but the problem is with the parking brake and not the actual brakes for the car. The warning I am getting on the instrument Panel is "Warning- Parking Brake" even though the parking brake is disengaged.

I just took apart the center console (again) and bought a new handbrake switch at Porsche of Southampton (Nice people). I inserted the wire plug into the the new switch and pressed it with my thumb and the brake light still will not go out.

So now there is a problem with the wiring harness somewhere. I traced the yellow and Brown/white wire up through behind the radio and it joins into a giant wire loom that goes up into the instrument panel.

Now I am truly stumped because this is electric. I reset the fuse for the instrument panel and that didn't work either. I also tried making a jumper and inserted it into the plug for the switch and that didn't work either.

semicycler

The yellow wire goes to pin 36 on the PSM control unit in the front left side of the frunk (hydraulic control unit controlling the ABS lines). The brown/grey wire goes to a grounding point #5 near the passenger a-pillar and dashboard.

Disconnect the switch from the wires and the PSM control unit from its connector. Check continuity between any good solid metal frame ground point and the end of the brown/grey wire. Then check continuity between the yellow wire and the connector on the hydraulic control unit. Also check the yellow wire if it's shorted to ground (probably the problem). If continuity is broken on either wire it's easier to run a new one than find and repair the break. Electrical wiring problems are no fun. Good luck!

mike9186

thank you Semicycler! Where did you come across this info? I'd love to be able to refer to a diagram is one exists on the internet!

semicycler

Try post #2 here: https://rennlist.com/forums/997-foru...ake-light.html