Anyone else have this problem? My 1999 Legacy keeps having no taillights becasue it blows a fuse for no apparent reason about every 6 weeks. First it was the #2 fuse, today it was the #5 fuse. The dash lights used to go out with it, but now just the rear lights. My mechanic is at his wits end.
Several possibilities and it involves the bulbs. Sometimes a bulb filament will get hot and sag. This can create a high current draw and possibly blow a fuse.
Another possibility is that sometimes tail lamp bulbs in Subarus have been prone to bulb contact wear due to vibration in the car. The bulbs have small lead contacts on them and over time the contact (which should be dome-shaped) will wear down, wallow out due to vibration, and may resemble a moon crater. This causes a poor contact and in turn increases the resistance in the circuit.
Increased resistance means more current and heat and over time the fuse simply gives up.
Yet another possibility is a faulty headlight switch or dash light rheostat (dimmer).
Just some reasonably wild guesses anyway.
“… Increased resistance means more current and heat …”
Awwwwwww, c’mon ok, you know better than that. Raise the resistance to electrical flow and you’re not gonna INCREASE current.
I’ll agree that there will be an increase in heat, but that would be local only to the bad contact, and would be unlikely to blow a fuse.
I think I’d be more likely to start looking for a bad wire that grounds once in a while and takes a fuse or two when it does. Start looking at the harness under the carpet, under the back seat, etc, etc.
Are those tail lights on the trunk or hatch? If so take a good look at the location that they go between the hatch and the body of the car. They will flex there and that is where they often short out.
What does the manual or wiring diagram say the #2 fuse services and what does the #5 fuse service?
A wire is bare and is shorting, somewhere. A red power wire leaves #5 fuse. It divides several times (still red) and goes to each light and to the trailer wiring connection. Where the wire bundle flexes at the trunk lid opening is a potential site for wires to rub on a metal edge. The trailer connector location is another possibility.
If you can’t find the short, you can splice in all new red wires.