New battery, car still dead as doornail

LOL!!! Yeah, how about a complete over haul on your electrical system. new EMC, Radio, clock etc..

If you're lucking, you could of simply blown some fuses ..

Do you have a schematic of the electrical system? Connecting the battery backwards will blow electronic gizmos and some steering diodes. 1990 is late enough to have an engine computer and that may be toast.

But check fuses . . . a large fuse on the battery wiring may not look like a fuse at all (that's another place a schematic comes in handy). There could be a "fusible link" (piece of wire) designed to blow in the event of a backwards connection. Sometimes physically close to the alternator. With the battery in backwards, there's a high current from the battery through the alternator diodes to ground (they are forward biased in that case, with nothing but the small resistance of wiring to limit current). Start there.

Check all your fuses first and replace the ones that are blown. If you replace all the blown fuses and still have problems you may have damaged some electronics.

Roger, not with the little bitty fuses but something much larger or piece of wire designed to open with over current.

Thanks, I just checked some of the pertinent fuses and, unfortunately, they are okay. I wonder if replacing the lead clamps might make a difference. They're pretty clean, but are old enough to vote!:)

This car is a good old boy and I hate to trash it.

Follow the positive battery cable away from the battery, it should go directly to the main fuse which should be around 60 - 100 amps. It should be blown, replace it. If it doesn't pull out you may have to unbolt it from underneath. If you have no power at all you still have a blown fuse or fusible link.

You need to get a mechanic who understands how to read a voltmeter and diagnose the problem. I cannot diagnose a problem when the only facts known are " I put the battery in backwards now it don't work".

Nope... The battery clamps are probably OK. There is a chance that the heavy cable from battery negative to chassis (or engine), or the cable from battery positive to the starter or starter relay is loose. Check the connections on the other end of those wires. If they're tight and clean (not corroded), then they are likely not the problem. That said, there's a 99.97% chance that you've damaged the car's electronics (computers). Your ECC (Engine Control Computer) is the guy that controls almost everything under the hood. If he's dead, then your car is essentially dead. Haul or tow the car to a *qualified* service facility for a thorough diagnosis. If it's the ECC, make sure your Master Card and/or Visa are in good standing. Judging from your description of events, the car might be beyond economical repair.

Main fuse? This one is not in the little box with the rest of the fuses?

I had a similar problem with a Hyundai Accent. Exactly the same symptoms as low low battery OR corroded battery terminals... A hydrometer said the battery was OK, a voltmeter said the battery and the terminal connections were OK, fuses were OK, and I was stumped

UNTIL I saw some small copper bits on the driveway.......

It seems that mice or squirrels had made a little space for themselves beside the battery and there was a wire in the way so they just chewed it out to make more room.

Fortunately, they had left enough lead at the connector that I could splice/solder in a jumper to repair the missing 3 inch section.

I never did find out which wire it was since once the problem was fixed I lost interest. I THINK, however, that it went from the positive battery terminal to the fuse box, but I can't be sure.

So, you may have some missing wire sections.

This has happened to me in this car, my truck, and twice in ,my motorhome. Mice and/or squirrels....

Good luck.

Andy in Eureka, Texas

AOK, thanks a bunch. I'll do a little investigation on this tomorrow. Thanks to you too, Andy and Mike, and Dave..

As has been said: high probability electronic items are smoked.

I start with the lights, then try lights+horn.

A voltmeter is a pretty lousy tool for troubleshooting this (well, after an initial check of the battery). The light-bulb probes they sell in auto parts departments are better for this--or you can make your own with any auto bulb.

Unlike a voltmeter, because these PULL SOME CURRENT, they are really good at sorting out a YES from a NO from a MAYBE. You can also tell Pass/Fail out of the corner of your eye.

Clip the lead hanging out the end to a part of the body and start probing with the point. When you stop seeing it light up, back up. If you can't get anything from the body to the + post of the battery, the ground connection from the battery is open.

Start out by seeing if the headlights light, that will tell you if there is at least some connection between the battery and the rest of the system

Oh - oh !

The earth strap bonding the engine to chassis is probably open.

Graham

Believe it or not I have once stupidly done the same (just brushed the terminals thankfully) but it seems everything was reverse protected.

Graham

Unless the original battery was shot (and even if wasn't charging well that's probably because there were only a few strands left of the earth strap), let's hope they'll take it back then.

I made just the same mistake when an earth strap failed on a car of mine. Halfords took it back though.

Graham

Mike wrote:>

And follow the damn NEGATIVE connections all the way to the engine block too.

I know one lass whose negative connection to the block was relying on the accelerator cable. Come deep winter and more cranking amps, the cable blew like a fuse ! And I'd warned that as a recent secondhand purchase it needed a good look over for any potential sillies but girls just can't think that way it seems, you know the "but it was working" mentality.

Graham

Not all cars are the same. Don't worry.

Graham

At least one other person here has some brains. The symptoms are classic.

Graham