Hey all,
My wife left the lights on and drained the battery. Tried to jump start. Initially it barely turned over about twice, and then completely died. Put a new battery in and it still will not turn over. I get no dash lights, head lights, or dome light. The only thing that I know works, is the horn. I looked and the main fuses and the ignition fuses and they all seem fine. By "looked" I mean I visually inspected them, no ohms testing.

Could this be a ground problem or an ignition switch problem, or something else I am just not thinking of? I doubt the ignition switch because I just replaced 2 years ago, but you never know.

Thanks.

 

Could be bad connections at the battery. You should check with a voltmeter to see if the battery terminals and main fuses have power. Do this with the headlight switch on so the system has a load on it.

The horn is actually pretty far down the chain of fuses. But it doesn't draw much power compared to other stuff, so it could potentially work with a bad connection at the battery.

 

This may be a shot in the dark but you may want to have the new battery checked under a load. Even new battery's can have bad cells.you may also want to use some emery cloth on the new battery post's and the cable connections to the battery. Good Luck

 

Well I cleaned and reseated the grounding wire. Made sure I had 12 volts coming off the battery. The main fuse shows 12 volts going across. The only other fuses that I know for sure that work, or are getting power, are the stop lights / horn and the hazard lights.
Still no power to anything else. I finally caved, out of frustration, and took it to a shop.

 

The problem has been fixed. The 80 amp main fuse was blown. I don't know why I was showing voltage going across it. I was probably checking it wrong. The gap between the metal in the fuse was so small, the only way to see it was under a bright light after removing it. It did not show any obvious signs of burning or melting, which is was I was looking for.

So if you have a similar situation where the engine will not turn over and you have no lights except for tail lights and hazards and the horn still works, check your main fuse or replace it. Save yourself a $115 repair bill.

We all learn from our mistakes. Gee, I feel smarter already.

 

how much would the fuse cost by itself? would a resistance test across the fuse been more accurate?

 

If you measure a voltage difference between the two ends of a fuse in circuit, that means that it is blown, not that it is good. Another test is to measure for voltage from each end to ground. On a circuit that is supposed to be live all the time, there should be the same battery voltage from both ends to ground, indicating that electricity can pass through the fuse.

Installing the battery backwards will blow that fuse. There are two kinds of batteries, the 51 and the 51R, the only difference is the + and - posts are mirror image on the Reverse one. Make sure to get the one that matches how the cables in your car are arranged.

Connecting jumper cables backwards is also likely to blow the main fuse, especially if the battery in the car is completely dead.