mike9186

I posted in the summer how I was having a problem with my handbrake warning light flashing intermittently. I replaced the switch under the handbrake twice and the problem remains. It also seems related to temperature/humidity and occasionally bumpiness on the road.

I took it my local mechanic and he said that the wires going to the switch all tone out fine and the problem lies inside the PSM (the control unit in the frunk) and it needs to be replaced.

I did some searching here related to PSM problems and found this:

"Was at a recent PCA tech session and the recommendation was to not jump start the modern cars as it sends a huge power surge into all the various computers in the car..and that this can show up immediately or much later depending on what been fried."

Well last spring I was staying at someone else house and left my lights on and had to jumpstart the car and it seems that this Handbrake Light problem is now occurring after this jumpstart event.

The mechanic priced out a new PSM unit and it is $3600 from Porsche!!!! So now I am on the hunt for a used PSM unit. Does anyone know the exact part # for this unit and the best place to find a used one?

I asked if there was a way to bypass the switch all together and I guess there isn't.

Thanks!

semicycler

There is a control unit attached to the ABS hydraulic valve block in the frunk on the left side. The parking brake contact goes to pin A36. This control unit is part number 997.355.955.06 and is sold as a complete unit with the valve block.

$2900 new: http://www.sunsetporscheparts.com/po...=abs-pump-assy

There's a used on on eBay in Great Britain for $200 plus shipping. Not sure if I'd go used with an ABS component though.

Try searching the part number with dots, dashes, with and without spaces. (997.355.955.06, 997-355-955-06, 99735595506, 997 355 955 06). As always, verify your part number with your mechanic.

mike9186

Thanks Semicycler!

I found found a unit on Ebay with the same part # and almost the same code on the bar code for $450 so I went with that. It was taken from an '05 that had 16k miles.

I'm chalking it up to me jump starting the car with cables so I also just bought myself a battery jump starter on Amazon so I don't have this problem again. This is quite the expensive mistake!

voiceprint1

so your not supposed to Jump the car with cables at all? I asked this question before and got no reply.

Mik9186 you bought a battery jump starter instead?

mike9186

I was unaware about this as well until I started to do research on finding a replacement PSM/ABS unit. When I went back the the mechanic and told him I found one I also asked him about using jumper cables and he told me straight up that in modern cars they are a no no.

So yes I bought a $50 Beatnik battery jump starter on Amazon to use instead of the jumpers. I've read good things and it is nice to be able to jump a car without the need of another car.

Petza914

I could see how jumping from another car with its engine running and charging system putting out over 14v could be a problem, but if you use jumper cables from one car's battery to the one in your 997, it would only offer to your car s normal voltage level, which is essentially the same thing you're doing with a jump box, so I don't see that jumper cables in and of themselves are bad, you just need to use them differently on your 997 than the way they were used in the old days. I have a very neat set that also correctly set the polarity so even someone who doesn't know how to jump a car can't fry either car's electrical system. I leave them in my wife's car just in case.

mike9186

I thought the same thing too. Maybe it is pure coincidence that my problems occurred after jumping the car, I'm not 100% sure. I do know that the lithium battery jump packs are cheap now so I'm going that route now.