chaadster

Hi everybody!

I've got this problem where if I activate the rear defroster by pushing the button on the pod in, it will illuminate, defog, but not shut down.
I understand it should do so after 15 minutes or so. Mine will stay on (i.e. switch lighted) even after the car is turned off. It will drain my battery to the point where the car doesn't have enough juice to start.

I haven't used the defrost mode (switch turned), so I'm not sure if that shows the same symptoms.

I searched the forum, and it was suggested that a "stuck" relay can cause current drain in some cases. Does my situation sound like a relay problem, or something else, such as a timer circuit somewhere?

Any help is appreciated! Thanks.

Jerry 87 928S4

I had the same problem and it was the relay. I believe you can switch that relay with the horn relay to test this. Check the relay chart to be sure.

chaadster

Thanks, Jerry! That'll be job number one in the morning! I'm pretty electrically ignorant-- I'm not even sure of what a relay does-- so I'm thankful for the tip.

Dave H.

when you turn something on with a switch, it sends a small current thru a coil in the relay, creating an electomagnet. this magnet draws closed a set of contacts which then passes a higher current to the load (headlights, etc.). thus protecting the somewhat delicate contacts in the switch.

this is why people to run very high wattage headlight bulbs without a relay often melt their headlight switch.

relays get a lot more complicated than that, with timers and delays etc., but that's the basic relay...

chaadster

Thanks for the explanation, Dave. It seems then that the relay would be responsible for the time delayed shutoff function, not some external timer?