ABS off and PSM light on after parking for a day, what could it be?

[rondocap]

So for a few times now, when I had the car parked for a day or so, and I turn it on, the PSM and ABS off light both come on.

They come on as soon as I release the parking brake. I noticed that the car has to be standing or about a day or so, and sometimes it does appear to happen more if the car is on a hill or there is a lot of moisture and humidity outside. Not sure if that is connected.

From searching the forum, I narrowed it down to possibly the brake switch light that may be bad, or possibly the alternator? But most likely the brake switch light. Where is this and how do I get to it if it is?

Anyone else have any idea what it could be if not that?

[smagerstein]

Hi

This happened to me about a year ago,

ABS and PSM both had the same symptoms, after about a month the lights stayed on permanently. Turned out the ABS module just failed ??XX?? They say this is very rare.

Porsche quotes something like over 2000€ to replace the part, I ended up buying one on ebay from a wreck (lots available, but you need the correct part number, there are a few), It was under 150€ and the stealership charged about 100€(1hour work) to replace it.

All was then good, no problems since.

Cheers, steven.

[rondocap]

a little update - I suspected it was the brake light switch, and I was right. I ordered a new one from Pelican Parts.

Incidentally, I did not even install it - all I did was make sure the original switch was really pushed in good, and sort of moved it around a bit. That seems to have worked, I have not gotten the light on since, and if I do, I'll have the new switch ready.

Here's basically how I knew it was the switch: Light came on. I touched the switch, and then the light would come on right away, like never before. Then I touched the switch again, and made sure it was well seated. Light never came on again.