ABS issues

Ok, I'm still trying to get my ABS up and running.  I think the issue is that I don't have the correct signal from the alternator to pin 10 of the harness.  Currently, I only have one wire attached the to 4-pin connector at the alternator.  That wire, which is attached to "L", goes directly to my ECU.  I tapped into the "L" wire for my alternator signal for the ABS.  

Does anyone know what signal (voltage) the ABS is looking for to activate the self check and startup?

when you find out can you just put a resistor in the line somewhere?

Ok, just checked and the wire from the ECU to the alternator "L" is switched 10.5 volts. Will someone check to see what the Porsche blue alternator wire output is?

Did a bit of rewiring on the ABS today. Moved pin 10 to a fused switch on my painless box but still not getting a anti-lock light to come on when 10 goes hot (and yes, I checked, the light works). Current setup has pins 17 and 18 to my main fuse box on a 30 amp circuit (always hot as long as the kill switch is on). Pin 15 is on a fused ignition switch. Not sure why I don't get the light when I turn on pin 10????

That is odd. Perhaps your ground isn't good enough. I originally tried grounding the two wires from the ABS pump to the same point as the main battery ground strap. I never got the anti-lock light like your saying and the alternator didn't properly charge. But when I made a new ground point of it's own for the ABS everything worked. But, of course, the main difference with mine is that my pin 10 goes to the alternator wire after the dash idiot light.

Rich

Hello Rich, Lemming so how are the ABS brakes working, when running right. This is something I am considering do for my car.

Rich, I'll try moving my grounds.

Kevin, mine is still not working, so can't answer.

I'm currently struggling to get mine to work as well. My "Antilock" light is on constantly. Going to check how my alternator is wired, look at the grounds, then check over the ABS relay, wheel sensors, wheel sensor wiring etc.

Guess I'm the lucky one. The ABS is great! It really is an amazing technology even if part of the point for me building an 80s track car was to get away from all the electronic crap on modern cars. But the Boxster unit in the 944 manages lockup as well as my '01 Audi and '06 Toyota. For track use, it lets me dive into the corners deeper and prevents trashing tires early with flat spots. YMMV

Rich

Just moved the ground point to the engine, still no light when I trigger the alt wire.

Do you have the wiring in the dash that lights the ! light? My alternator trigger wire goes in at the firewall and the ABS connection comes out behind the glove box. Wiring diagrams were in that rennlist thread started by tony.

Rich

Rich L. wrote:Do you have the wiring in the dash that lights the ! light? My alternator trigger wire goes in at the firewall and the ABS connection comes out behind the glove box. Wiring diagrams were in that rennlist thread started by tony.

Rich

I'm not sure that is necessary, according to Duke in the RL thread "If someone wants to simplify the wiring just a little bit you can run both #10 and #15 to a switched power source. I got to test my ABS system yesterday for the first time. Felt a bit strange to have such a quick ABS modulation in a 944"

Below is the pinout in case anyone is looking for it.

Sweet!

Ok, managed to work on it just now, pulled the harness plug and started checking ground and hot pins. Turns out that Pin 15 was not getting power, which is now corrected. I have 12V on 10, 15, 17, and 18 as well as pin 14 when the brake pedal is depressed. Ground is fine on 16 and 19. When I power the system up, I get a few clicks on the ABS pump that sounds like solenoids??? However, I never get an ABS light flash. Not sure if that is a problem or not as I am not running Pin 10 off the alternator and thus the car does not need to be running for the ABS to function.