I have a 2005 RAV4 with 20,000 miles. 2 weeks ago I had UHaul put a trailer hitch on. Thursday I towed my boat to the water, towed the empty trailer home, and drove to a store. Leaving the store I found the HVAC fan, the speedometer, and three of the power windows were dead. Everything else, including the tail/brake lights and driver's power window were working normally. I checked all the fuses that seemed relevant but found none burnt out.
I took it to a dealer. He says that a 10a fuse that controlled all those items was burnt out. He replaced it and everything worked okay. He could not find anything wrong, but feels it is probably the trailer hitch. He recommends I replace it with a Toyota hitch. I did not check that fuse, since stuff on it was working.
I see two serious problems with that explanation:
1) The tail, brake, and dome lights are all on that fuse, but worked normally.
2) The 4 power windows are on that fuse, but one of them worked.
I asked him to explain these discrepencies, but he couldn't. Hopefully someone here can, or can give an alternate explanation for my problems.
I would go back to the hitch installer and have them check the wiring job. Did they happen to install a electric brake surge controller or any other component/device when they installed the hitch? If it continues to give you problems, you can install a ten amp circuit breaker for testing purposes to help find a possible wiring short or shorted component.
My guess is that the wiring for the trailer lights (not the hitch itself) was done incorrectly or a trailer light adapter was not used. This can cause some pretty strange electrical problems.
I concur - if there's a problem it's in the wiring for the trailer connector most likely, or there is a wiring fault in the trailer light wiring itself that popped the fuse when it was hitched up. Disconnect the trailer, problem goes away.
Although if the circuit that popped the fuse has absolutely nothing to do with the trailer, that might point to the competency of the installer... Have someone else at that shop check his work.
On boat trailers, if the lights and wiring isn't waterproofed properly it'll cause all sorts of fun during and after submersion, especially in electrically conductive salt water.
I was going to ask about an electric brake controller, but you can't use electric brakes on a boat trailer - it's hydraulic brakes or nothing. Unless you have the new electric-pump-over-hydraulics...
One other thing to consider, sometimes fuses just crack and fail from a factory defect, not because of a short circuit or overload. Make sure you have the right size fuse in that slot, carry a few spares, and see if it happens again: Once is chance, twice is happenstance, three times is enemy action.
And the comment about "the hitch is the cause, replace the hitch" makes me very suspicious about that dealer's motives, because the hitch is purely mechanical and nothing to do with the tail lights. And it's NO WAY associated with the power window and heater fan circuit.
If it's a properly designed and installed aftermarket hitch it is no worse than the aftermarket hitch Toyota buys and slaps their name on to sell through the dealers. (And they also slap on a very healthy profit markup at the same time.)
Advice: If you are hooking up a trailer with lots of lights on it (anything more than the bare basics of one set of Stop/Tail/Turn and one set of side markers) consider going to a 'relay trailer light converter' that supplies all the trailer lights from a separate fused battery feed. Then if there is a fault in the trailer wiring you only pop the trailer light fuse, you don't lose the car lights too.
They size the light wires on cars to be just big enough for the factory loads - you can add one more lamp on each circuit for occasional use, but ANY more than that is just asking for trouble.
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