ntivos

I need some help I have a '93 964 recently I change the booster switch, after a while my abs and 4 wheel drive lights are on, speedometer is not working and no rear spoiler as well.
I looks like the brakes are working, booster pump and switch are working fine no hard pedal but the lights are still on after I start the car.

Thank you

dlpalumbo

I assume you changed booster switch because pump wasn't running. Now it is.

Have you bled the booster?

Did speedo and spoiler work before you changed the booster switch?

ntivos

Yes bleed the system. Switch was stuck that’s the reason I changed it. Everything was working fine before and after the switch replacement.

cajonfan

Has the PDAS/ABS controller been removed recently? I think the speedometer signal and spoiler control input signals both come out of the PDAS/ABS controller on MY 93.
Perhaps things will improve if the connector is cleaned and re-seated.

ntivos

PDAS/ABS no has not been change ever I’m the second owner, do you think that’s where the problem might be? Thx.

bw-porsche

One really important thing to do is to make sure the brake fluid reservoir is topped up to the limit. Otherwise you get warning lights appearing on the speedometer!