2003 Outback Rear Defogger not working

[subx]

I have a 2005 Subaru Outback SW.  The rear defogger is not working.  Furthermore, when I push the defogger switch, I measure no voltage at the rear defogger grid positive connector (on the passenger side).  

 

1) All fuses are fine (under dash and in engine compartment)

2) the defogger switch is fine.

3) the rear window grid is fine.

4) when I depress the defogger switch, I hear a "click" so I'm guessing that power is getting to the relay (which may/may not) be working?

5) the section of wire leading to the defogger positive terminal that passes from the rear of the car to the tailgate is fine (from other posts, this seems an often problem).  I didn't check the "negative" wire passing from car body to tailgate, but actually disconnected the negative grid terminal wire, and connected a "substitute" grounded wire to the negative grid terminal.  Then, I depressed the fogger switch (i.e., applied voltage to grid) - and still no voltage to grid.

 

Here's where I could use some advice from the experts.... 

 

1) when I remove the fuse from the engine compartment, and depress the defogger switch, the orange led light still comes on. Is this normal?

 

2) What are my next troubleshooting step(s)? 

 

3) I know from the wiring schematic that there is a relay(s) (& I read somewhere there is also a timer?).  Where is the relay located? below dash fuse panel? behind fuse panel?  Also, what identifying marks will be on the relay so I am certain I have located it?

 

I really appreciate any advice.  I'm stuck.

 

Thanks

 

 

[subx]

correction - the car is a 2003 Subaru Outback, NOT a 2005

[Fairtax4me]

Relay control side operation is independent of the grid. The light in the button works when the relay is commanded on, regardless of the grid gets power or not.

 

The relay is in the fuse panel under the dash. Power for the grid comes from the fuse in the main panel (underhood) through the relay, then through a few connectors as the harness runs through the car.

Check for power getting through the relay if you can. try a different relay in its place if there are any similar relays.

 

There are three connectors in the right rear corner behind the trim where the body rear harness joins to the gate harness as it runs up the D pillar. The wire color for the grid power wire is the same the whole way from the relay to the grid so you should be able to find the right one to check for power there.

 

The other connector is behind the lower kick panel under the the right corner of the dash.

[subx]

Thanks for the advice Fairfax4me. I have several spare relays. I'll take a look under the dash tomorrow to locate the specific relay. When I depress the foggier switch, I hear a relay, so hopefully the 'click' will guide me to the correct relay. I'll let you know how I thing progress. Thanks again for the advice.

[brus brother]

I know you said it seems fine but I would check for continuity on the appropriately colored wire before and after the rear hatch harness as it goes from body to hatch. Mine wasn't obvious at first glance.

http://www.ultimatesubaru.org/forum/topic/163213-broken-wire-to-rear-hatch/?do=findComment&comment=1356799 see pic in post #4

Edited December 10, 2017 by brus brother

[subx]

Well, I swapped the relay. No luck. I did note that the timer appears to be working as the orange switch light goes off after about 15 min.

 

I'm guessing what remains is to chase down some short somewhere between the wires at the back of the car and the relay, correct? I noticed that a red wire with yellow stripe leaves the relay plug, and a red wire with blue strip connects to the positive terminal of the window grid.....Any idea where the wire change occurs? I guess I should check the locations along the path where connector(s) occur...? Any ideas where, along the route, I might find connectors?

 

Brush Brother .... I already checked for continuity on the "red w/blue stripe" wire at 1) the point where it runs from the the back of the car before running thru the accordion rubber tube, and 2) where it connects to the grid ---I wish that was the problem but the wire checks out for that rear section of the path....thx anyway. Darn.

 

Btw, when I depress the defogger switch to energize the circuit (ignition on), I measure 0 volts across the 20 amp fuse in the engine compartment.

 

Any more advice (besides use an old t-shirt to wipe off the window...!)?

 

Thanks

[Fairtax4me]

tw, when I depress the defogger switch to energize the circuit (ignition on), I measure 0 volts across the 20 amp fuse in the engine compartment.

Black meter lead connected to battery ground?

Checking voltage at the pins on top of the fuse? How about at the terminals with the fuse removed?

[Bushwick]

Is the rear defrost switch on these only 2 wire? I know when I retrofitted a seat heater from a 98' Outback, the switch was only 2 wire i.e. (+) and (-) and everything from the switch lighting up to the temp timer in the seat was handled through those 2 wires. If the rear defrost switch is more than 2 wires (going into it at it's connector), it might actually be defective i.e. it's lighting up but not sending the initial signal to turn on. If it's actually working OK, then start tracing the line from the switch -> forward until you stop getting power.

[Fairtax4me]

Switch is built into the HVAC control panel.

Switch works if The relay clicks on/off as it's supposed to when the switch is pressed. The switch on this model doesn't directly control the relay, it signals the ECU to ground the relay coil.

[subx]

Thanks all for helpful comments. I'm out of town for a couple weeks. When I return I will try to trace down the wires as suggested and let you know what luck I have. I will also do the fuse tests as Fairtax4me states. Thanks