DashingDaryl

I just purchased a 2010 RDX Tech Package with about 125,000 miles on it. I am super excited, but I had to have it towed to my house because it wouldn't start.

After putting in a new battery, i found the main 100/30 amp battery fuse was blown.

I purchased a new one at the dealer, but am hesitant to put it in without knowing my it blew in the first place.

I assume it has to do with a short in the wiring to/from the battery or maybe the alternator.

Anyone have any other ideas?

Could it be because the previous owner put the battery in backwards and then flipped it around to the right way?

Just as a reminder, the battery fuse is Fuse number 1 in the engine compartment fuse box

yanga001

I have seen those blow on VW's from a reverse battery so i would say it is possible. You can find the dealer service manual floating around and trace out the lines. I suspect that the main fuse is so far upstream of other fuses that if you do have a short then its on the main low gauge wires or within the box itself. If their are yards around you then try to pull them from the self service scrapyards next time. They rarely go out and are unlikely to be pulled as they require a screw driver.

Jumping it with a wire will tell you if your car can run, but it wont tell you if you have an intermittent or dead short (unless the wire melts, then you know you have a dead short).

However, if the car runs okay then its unlikely you have a dead short as it would run very poorly if power is being sapped by another system.

My advice would be to first jump it with a thick wire, and then if it runs then use the main fuse you bought. If it was a reverse terminal then you will have many other systems down/fuses blown. Those you may need to track down.

Also these cars have a habit of killing starters so dont be surprised if the starter is bad.

Hope it helps!

DashingDaryl

Thanks @yanga001 . I appreciate the excellent ideas.I was going to disconnect the starter and the alternator in case either of those was shorted. Then I was going to hook them up one by one to see if the fuse held.

But someone showed me this video, which gave me the confidence to try it after I took the old battery out. I AM SUPER HAPPY to announce that it worked. The fuse held and the car is driving great!

NBP04TL4ME

I don't have tons of experience with blown main fuses (1 or 2), but when it has happened in my circle of friends and family is usually is from reverse battery connections. Glad you got yours sorted out