Fans eat my battery......

[FabricGATOR]

Just a quickee......

Yesterday I drove a bit in the rain. Utilizing the "Defroster Effect" a few times (just love it). Anyhow, when I came out of the mall my fans were still running and again when I got home. I pulled fuse #10 so I could get started in the morning and they stopped.

This morning the battery was dead and I imagine I powered the relay all night thus killing the battery. Just so happens that someone came to where I work today in another 1987 944 so I talked them into letting me try a relay swap and thus determined that the same symptom happened with their functional relay in my car.

I'm gonna guess that the thermo switch in the radiator has gone kerput, thus telling the relay to power up the fans (both of them)

Is this sound troubleshooting or does anyone know of something else I shoud test before spending my last 10 bux on a new thermoswitch. I mentioned that I used defrost effect because it uses the A/C compressor and when the Ac is used doesnt it start the fans? Warm radiator runs the left fan as needed under N/O (normal operation) and hot radiator kicks in the second fan if needed to assist the primary fan in removing the heat.

I'm glad it doesnt seem to be the relay because it looks expensive inside! (Four contacts/coils, a dozen resistors, half dozen capacitors, diodes, and a IC chip or two) .... anybody know what its worth?

Please help me fix it right the first time!
Thanks!

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[carsonmx114]

when you plug your relay in can you feel it click as it makes contact? If it doesn't click it is stuck on, if it does click it is getting a signal from the thermo switch or the defrost switch. the fans are two speed units they sould both run at low speed for moderate temperature situations and at high speed for more extreme temperature situations or when the a/c compresor is runing. The next time the fan stays on more than a couple of minutes try unpluging the thermo switch, this should tell you if the thermo switch is bad. watch out for the fan it's close to the switch. If the fans keep runing with the thermo switch unpluged and the relay clicks when you plug it in I would guess you have a climate control panel problem. also a two speed thermo switch from a late model vw will fit your car and may save you some money.

[zzpza]

carsonmx114 knows his stuff. exactly what i was going to say...



j.

[FabricGATOR]

Yea, I agree that you both know the system. I know it pretty good myself, and was looking for confirmation (second opinion)...... Thanks and I didnt know about the VW option although it makes sense!.... or is that cents?
I had originally thought thermo switch, relay, or climate control head. I had swaped a relay from a friends car and it was the same symptoms. I swapped my climate control head with another I had with broken plastic and again, similar symptoms.... nothing changed. I ordered a new switch from NAPA but they got the wrong one so I'm still without the car, although I do run it for short distances while monitoring the temp guage because I'm tired of plugging and unplugging the relay. If i get caught at the railroad xing I 'll shut down or go into defrost effect to maintain green zone. Thanks again and I'll report the final outcome, Kurt