garrett376

Hi Guys, yet another time I've decided to decipher the cryptic instructions on the carreracup.org website on how to rig the ABS over-ride switch. And again, it makes no sense (I thought maybe I just couldn't follow it the first dozen times I read it...).

Has anyone ever installed an ABS over-ride switch on a 964, and can give me a heads up on which wire is bypassed to kill the ABS? I wonder, also, if this installation would vary between a C2 and C4. Hopefully the over-ride is "south" of the brain so it would not matter which model is involved.

Thanks

Tom W

Well, I don't know about a switch, but I do know that if the fuse is pulled or blown it accomplishes the same thing. It's either #17 or #18 (I forget which). When I tried to drive without the ABS at the track, I quickly learned that I was into the ABS more than I ever thought and I flat-spotted the tires pretty quickly. If you are like me and need to learn to brake less (so you don't over brake for the turns) and have some nearly dead tires, removing the fuse could be a good simple way.

All this is true on a C2 anyway. The braking system on a C4 is a bit different, but the fuse may be worth a try as it's very easy and also simple to reverse.

Red rooster

The fuse sounds like a smart idea. What that note is describing is a switch to remove power to ABS relay R34 coil by making the feed to relay pin2 ( contact 15 )from Central electric C32 ( black wire ) , switchable.God knows what would happen !On a C4 the ABS opens the diff locks etc for stability.Doesnt sound like anything I would try .
Geoff

Bill Gregory

It's really easy to do....Good idea to disconnect the battery first. Then open up the central electric box with fuses and relays. Undo the two screws holding the board down in the box. Lift the wire bundle and relay/fuse board out of the box and turn it over. Find plug C. You can easily remove the entire plug C, or, and I think easier, find the black wire at C3.2 (which, as I recall, is the only black wire on the C plug). At some point on the black wire cut it, and splice in a wire to both sides of the wire, which forms the two wires that you'll run to the ABS Disconnect switch. You might want to solder the connection and use shrink wrap tubing on each connection. If you have the Bosch switch, it's normal, connected position is with the switch out, then you tap it to disconnect the ABS. When the ABS is disconnected, the speedometer doesn't work. You'll also want to disconnect the klaxon horn that sounds (warning, warning, idiot, your ABS has failed) when the ABS is turned off. You may want to review wiring diagram 92 sheet 4 (C4 ABS) and sheet 4A (C2 ABS) in the factory manual. My quick read of it says that the C3.2 connection is the same on both C4 and C2.

On the Carrera Cup USA website, there's a picture of the disconnect switch installed to the right, bottom of the speedometer, where there is already a cutout in the dash panel:

garrett376

Oh yeah... Bill, you're the man!!! Thanks so much for the tip, I appreciate it!

I wonder if that spot is a good one for the switch... I'll have to see. Either way it is a switch that will be tough to remember to push during an off-roading event!!!

Bill Gregory

In that position on the dash, the switch is just under the right hand, very easy to smack it, as it's a push-in switch.

Oddjob

Bill,

Do you know if that wire is power from the battery to the fuse and relay, or is it power from the relay to the ABS control unit?

Bill Gregory

The black wire connects ignition terminal 15 and the ABS relay.

Oddjob

Thanks, thats what I needed - now I just have to find the ignition wire/terminal on my 944T!

Cupcar#12

We also have the How To Doc from Andial posted on the site (with part numbers) and pictures of the harness and switch (more part numbers too...)
http://www.carreracupusa.org/Race/el...electrical.htm

Hope that helps - I have not installed mine yet but will in the coming year

Bill Gregory

FWIW, I did check Porsche Motorsport in Europe on the wiring harness, and they'll be glad to provide one for $1200.

garrett376

Yowzers, that's some costly wiring.

kgorman

Garrett, did you ever do this?

Larry Herman

I have an ABS kill switch on my car, but it's purpose is to reset the ABS if it locks out. I have had to use it several times on track, and knowing it's there, it didn't take much brain power to hit the button.

ThomasC2

Digging up this old thread!

I've had this ABS-switch for many years and it works as it should, meaning no ABS, master alarm, alarm sound. I did use the power cable on the realy instead of the black No 15 as Bill says.

There's a light bulb inside the **** and for me the bulb is lit when the **** is out and ABS is on. When I push in the **** the light goes ut. I thought this was correct but some time ago I learned that it should be the other way aorund. Meaning, when the ABS is on the **** is dark and when you disconnect the ABS the **** should light up as a warning.

The other day I checked this on a friends -91 Euro cup and after replacing a broken bulb it worked exactly as mine - with ABS it lights, no ABS it is dark.

when I read the instruction on carrerarcupusa.org it says the same thing in hand written note.

So can you guys who knows or cup car owners confirm what set up is the correct one?