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mcveed · 03-06-2013, 03:43 PM

I recently had the misfortune to charge a dead battery with the polarity reversed and then try to install it in my motor home, a 2002 Flair. There was a large spark and I disconnected the battery. The battery has been replaced with a new one but nothing happens when I turn on the ignition switch. Can anyone tell me what damage I might have done? Is this a simple fix or a major disaster?

jland · 03-06-2013, 03:47 PM

You likely at a minimum blew the main fusible link going to the alternator its normally 150ish amp depending on the vehicle

BFlinn181 · 03-06-2013, 03:57 PM

Not sure hooking the battery up 'reversed' would create a huge problem IF it was the only battery AND you didn't try to start it. Fuseable link or fuse could still be the issue. Use a multimeter and see how far and where current is going. When it stops, that's where to look for the fuse or bad connection.

dieselclacker · 03-06-2013, 06:55 PM

I am curious as to how you managed to charge a battery backwards. I can't say I have ever heard of this.

mcveed · 03-06-2013, 08:04 PM

Quote:

Originally Posted by dieselclacker

I am curious as to how you managed to charge a battery backwards. I can't say I have ever heard of this.

Well, the battery was completely dead. When I hooked it up I guess I expected a reaction from the charger if it was hooked up wrong and I didn't check the alligator clips (not colour coded and very old). So the charger went ahead and charged it with the polarity reversed. If you don't check the cables from the charger and the battery is completely dead, its not hard to reverse the polarity. Problem is it's not possible to fix it.

mgscott4 · 03-06-2013, 08:40 PM

Check the Battery control center BCC under the hood drivers side. There may be circuit breakers that tripped. The circuit breakers are small silver things with a small button on the side of it. Push them in. Or your ignition relay is in there too, see if it clicks when you turn the key on. Then you know you have power to that point or not.

Did you try your AUX start switch? does it work?

Full-Timers · 03-06-2013, 10:37 PM

Probably fried the computer (PCM). And possibly the Transmission computer as well.

DriVer · 03-07-2013, 11:45 AM

I would rule out installing a known fully charged battery and try it again. It is likely that the old battery is shot and won't hold any charge. If nothing happens with a known good battery, then we'll speculate further.

gg · 03-07-2013, 03:54 PM

My 2 cents

1. Install a known good Battery.

2. Check headlights are they bright?

3. Ign switch turn to on - does dash lightup?

4 Ign switch turn to start - starter turn - engine run?

Also the Big 3 / SAE require( 1990 approx time frame) that ECM/PCM/BCM
(engine control, powertrain control, Body control modules) must work with 26 volts or reverse polarity on the Max volt side and down to 9 volts on the min side . This is to protect your new vehicle you loaned to the 16 year old driver and she trys to jump start a vehicle and connects it up wrong.

So I think the Modules are just fine. good luck

DriVer · 03-07-2013, 04:06 PM

Quote:

Originally Posted by gg

So I think the Modules are just fine. good luck

ME2!

tropical36 · 03-10-2013, 12:43 PM

Quote:

Originally Posted by dieselclacker

I am curious as to how you managed to charge a battery backwards. I can't say I have ever heard of this.

In the old days of the generator, I saw many and they worked just fine, except that the charge gauge read backwards. Going back a little further, one might remember that FORD used to be +positive grounded. Now which way does DC current actually flow.....pos to neg or neg to pos and that is the question

So, it might just depend on whether you're talking to a Physicist or an Electrical Engineer and my bit of trivia for the day...

DriVer · 03-11-2013, 09:14 PM

Quote:

Originally Posted by tropical36

So, it might just depend on whether you're talking to a Physicist or an Electrical Engineer and my bit of trivia for the day...

I'm not sure it it's still the same but British cars were what they call; "positive earth."

mcveed · 06-07-2013, 11:19 AM

Just to close the loop on this issue. After getting some advice from the mechanic at the local RV service shop I followed the heavy cable from the battery to the starter. There I found the melted fusible link in the line running from the starter to the alternator. Once this was replaced everything worked perfectly.