Radiator fan problem
 

'99 Boxster base. Both speeds of both fans work when the car is cool by jumping the relay socket and low speed comes on when engaging the A/C. After driving enough to warm the car completely, the passenger side does not come on low speed when the drivers side does. It will come on when the coolant temp rises enough to demand high speed. Neither will it run low speed by jumping the relay socket when warmed up. I can't see anything to cause this except the resistor. I've searched this site and Renntech and found lots of info, but nothing about intermittent problems. The resistor itself has a blueish tint on the end opposite the wires. Any wisdom appreciated.

I would replace the resistor. Not an expensive part.

Thanks for the answer. I had always thought a resistor would either work or not work.....a bit like a fuse. Looks like that's not true. I'll change the thing and hopefully be done with it.