gl2tosl2

I drove this morning and double checked, the a/c (not so pleasant when it's 40F out) and the blower motor seem to be working fine. The CEL came on in the same drive (I'd previously cleared the code). I checked the code when I got to school, and it was the same one, p1520. I won't be able to try shorting the relay return path (with the relay in) to ground until I get home.

I don't think I understand the path here. Or my wiring diagram is wrong. I'll have to try shorting the control side of that relay to ground (while the relay's plugged in) tomorrow and see what happens. According to my wiring diagram, the sub fan (not turning on) and main fan (turning on) relays have the same path to ground, except each has their own diode leading into the path. So wouldn't a problem further down the path affect both of them? I'll try this stuff tomorrow.

No, I just unplugged it. I didn't re-install the glove box yet, so it's still easy to get to. So I need to short two of the three connections? Which ones? Yes. I removed the relay and jumped the load terminals. The fan came on. I took the relay out and measured the voltage on the control terminals. One showed 12 and the other showed 3. This is when the other engine fan was running. I was refering to the control side. The wiring diagram I have (from the haynes manual) says that both fans should be controlled by one wire going into the computer. The diagram gives each their own diode feeding into that wire. It's a coil type. The control terminals have some resitance, I don't remember exactly what and can double check later, but I think it was between 100 and 200 ohms. I tested the relay by connecting the control terminals to +12 and ground and I hear/feel it click. The load terminals give no continuity when the control is open, and continuity when the control is closed.

I just tried unplugging the switch, and no change in behavior.

hi, In short: Where are the diodes in the fan control circuit? I can't find them. In long: This is all based on poking around with my multimeter and the wiring diagram in the haynes manual. I have a 1998 legacy outback. The computer is giving a p1520 trouble code. According to this page, there's a problem with the fan control circuit. The passenger side fan (I think it's the sub fan) is not coming on. If I remove the relay (inside the car), jumping the terminals turns the fan on. When the main fan is off, the control terminals at the relay both show 12 volts. When the main fan is on, the terminals show 12 and 3 volts. This leads me to believe that there is a problem with the diode in the circuit. Any ideas? thanks for any help.