Windshield wipers don't work unless headlights are on

[harmonyroadporsche]

I have a 2002 996 and the windshield wipers only work if the headlights are on. Some of the posts I've read indicate that the ignition switch may be the cause. Has anyone else encountered this problem? Are there relays, fuses or other thing I can check fist before opening up the dash and replacing the ignition switch?

[harmonyroadporsche]

I swapped in a new ignition switch this weekend but there was no effect on the problem. Since that was the most likely cause I'm somewhat stumped. Any thoughts on what I can try next?

[Loren]

Does your car have the rain sensor option?

[harmonyroadporsche]

Hi Loren. Thanks for the response.

Yes, I believe it has the rain sensor option.

[Loren]

If you notice in the schematic the wiper motor control goes through the rain sensor control.

I would check the rain sensor. Also the intermittent wiper relay and dash switch might pull the circuit down if they are not functioning properly.

[harmonyroadporsche]

Thank you very much for the wiring diagram! Where does the headlight switch fit into the circuit? Seeing this might help me narrow down the source of the issue. The control unit is the less expensive component to replace so I'm hoping that is the culprit.

[Loren]

Is this a Canadian car with DRL?

[harmonyroadporsche]

It is a Canadian car and should have daytime running lights, assuming that's what you mean by DRL.

[Loren]

The motor is controlled by the rain sensor control unit - I would start there. They were the same part for all model years so if you can swap with someone it might rule it as good or not.

[harmonyroadporsche]

Thanks Loren. I will attempt to swap out the Control Unit and see if that helps. Do you know where the control unit is located?

[harmonyroadporsche]

For those interested in the location of the Rain Sensor Control Unit this image should help.