View Full Version : Tail light troubleshooter
gmaxum
10-15-2005, 01:02 PM
Wonder if someone out there can take this troubleshooting to the next level.
The tail and side markers don't light. Flashers work. Brake lights work.
What I have found is that I don't even have power to the hot side of the fuse!
I would think this is where the circuit would start and all relay and switches would be 'downstream' from here.
Obviously I don't have wiring schematics, so if anyone out there in SVX land has any suggestions I would be highly appreciative.
gmaxum
10-15-2005, 08:59 PM
Upon further investigation I found the tail and illumination relay and thought for sure that was it. So I swapped it with the rear defog relay right next to it. Still nothing. So then I grabbed the relay and toggled the tail light switch on and felt and heard it switch. Then for fun I jumpered power over to the outside of the fuse and sure enough all the lights came on.
So the question is how am I not getting power from the relay to the fuse?
I have perused Beavs locker (he has some really funny clips here - check out 'Evil Twin') for schematics and found some good schematics, but nothing that shows me the route from the tail relay to the fuse. Perhaps it is all done on the backplane?
I dread the idea of having to take this panel off just because the top nut is all but inaccessible.
If worse comes to worse I will wire in a toggle switch to light these lights for now as this is seriously impeding my night life!
gmaxum
10-17-2005, 10:13 AM
OK and the final clue. For some reason the manual taillight function (the button next to the rear defrost on the dash) does bring the taillights on. But then they stay on even with the key off.
I have a feeling I'll be answering my own questions on this weird one. That's OK - I'm learning lots!
svx_commuter
10-17-2005, 10:35 AM
I was told that switch is for the parking lights and that Canada requires the parking lights to be left on when a car is parked on the road. So that is why Subaru includes that switch in all the North American cars.
When you turn on that swicth, I think your front parking lights should come on too. I don't know about the side markers and the switch function.
According to my copy of the factory manual page 35, the parking light switch is a SPDT fed by fuse #23, with one pole going to the relay and the other pole directly to the parking lights. From your description, it sounds like the fault is either in the parking light switch or in the wiring between the switch and the relay, or in very rare situations, a problem with the relay socket. However, you also said that you weren't getting 12V at the hot side of the fuse, but this would not be possible if the parking light switch actually does turn the lights on. The coil side of the relay isn't fed by this circuit, so the relay will still click on and off even if fuse #23 or the switch is bad.
KuoH
OK and the final clue. For some reason the manual taillight function (the button next to the rear defrost on the dash) does bring the taillights on. But then they stay on even with the key off.
I have a feeling I'll be answering my own questions on this weird one. That's OK - I'm learning lots!
gmaxum
10-18-2005, 09:42 AM
kuoh, thanks for your help. I think I know whats going on now. The parklight switch is busted. Looking for replacement now.
The taillight circuit needs to see power coming through the park light switch. Is that right?
Test before you replace. The parking light switch assembly is pretty to get out, and since it's an SPDT, it's also easy to bypass to verify that it is indeed the culprit.
KuoH
gmaxum
10-18-2005, 11:35 AM
No really, the park light switch is already busted. (not sure how somebody accomplished that!)makes sense though. When the switch is on it routes power directly to the taillights. When it is off it supplies power to be switched by the taillight relay.
Now I just need to find somebody who has one.
Or if you can live without the ability to manually turn on the tail light, reverse the wiring. You could even jumper power directly to the tail light relay. There's really no reason I can see why both can't be powered up at the same time.
KuoH
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