I've got a 88 GL d/r wagon with cruise control, SPFI and no A/C. I've been on usmb researching an electrical gremlin that has been annoying me. Follow this: I replaced the blower switch because the heater fan wasn't coming on. No luck....but, the heater fan works great when direct current and ground are applied via my little battery charger.

I probed with a test light the plug that goes to the heater/blower switch after unplugging it from the switch. With the ignition key at the "on" position I'm not getting any current from any of the contact's I probe. Test light comes on when I touch the cig lighter positive contact so I know the test light works. I need confirmation as to whether or not one of the four round relays inside the dash is for the heater blower? Ya know, the four that are lined up like little soldier's? I'm fairly confident one of them may be, but I'd like to know for sure before I dig in. Thankz.

Yes - the relay you are looking for has a white connector and on the contact side (larger wires) it will have a blue w/red and a green w/white. That is the blower motor relay.

 

GD

Perfecto. Thankz.

X2 - I had the same problem and it was the relay. I replaced the little 22amp Subaru relay with a common 30amp GM relay, they're everywhere in the JY, cheap new, and less prone to failure.

 

If your not getting power to the blower motor(test at the harness for the motor) you have another problem further upstream(fuse maybe), because unlike any other car I've worked on, the switches are on the ground, instead of the power wire, meaning the motor always has power, but only works when it gets ground. If you need a heater to get you by, just run an aux. ground wire to the motor and it will turn at full speed bypassing the relay and switch.

 

Josh

Yeah - Subaru uses a lot of ground controlled circuits. Makes them more robust because the power flows through a shorter path typically and thus a short will, more often than not, occur on a ground side and cause the accesory to run all the time instead of blowing a fuse.

 

GD

also just for anyone who looks over this page the heater switch is very easy to rebuild.. once you get it apart its pretty self explainitory just dont lose the incredibly small ball bearing and the holy crap is that a grain of sand?! small ball bearing. i did mine last night worked like a charm.. a lil bit of sanding and a new spring for the high power connection a lil scrapeing and good to go!

The trouble is most likely with the relay as you suspected. Sometimes you can confirm that by tapping on it with something like a screwdriver handle and that will turn on the device.