Installed battery terminals backwards

[VAL]

I accidentally put the positive to negative & negative to positive side on my battery. I know i fried something, but can't figure out what. Truck won't start at all, no power. If anybody can help, it would be greatly appreciated. Thanks.

 

[foamypirate]

Probably the fusible link on the firewall junction. I did the same thing, but noticed it as soon as that link started smoking (lol) and disconnected them quickly.

 

[HotRodPC]

At least you hope that's what you fried, and not the backside of the fuse block. IF the fusible link did it's job as it should, then you should be good to go.

 

[VAL]

Thanks Guys, it was the fusible link on the fire wall, all I need to know now is how to fix it? do they sell them at the auto shops? and what size fuse was it?

 

[Jims86]

Thanks Guys, it was the fusible link on the fire wall, all I need to know now is how to fix it? do they sell them at the auto shops? and what size fuse was it?

Yes, you should be ablemto go in and find a replacement in the electrical Isle, you can alsomreplace it with the proper amperage fuse, and holder....usually around $5+/-

 

[chengny]

Don't mean to bum you out, but;

While you're at the parts store, you might as well pick up an alternator.

When you reversed the polarity you probably wrecked the voltage regulator.

There are 3 diodes that form the rectifier section of the voltage regulator. The rectifier is used to convert the AC voltage to DC.

They are highly intolerant to reversed polarity.

Don't get fooled. When you renew the fusible link the truck will most likely start and run fine - for a while.

A truck with a non-functioning alternator and a fully charged battery can run a car for hours (or even a couple of days under minimal load). Eventually however, the battery voltage will drop to the point where the coil can't provide spark and the plugs won't fire.

 

[HotRodPC]

I thought of the voltage regulator too. If he's handy, he can pull the alternator apart and replace the voltage regulator himself for about $15 or so unless they've gone thru the roof like everything else. But, if you don't know what you're doing, then don't bother with that. Just get a new one.

But, come to think of it, it's very possible the fusible link saved the alternator too. The fusible link actually brings power in the back door of the fuse block right? And the alternator is actually out the front door of the fuse block, or vice versa as an example.

 

[89Suburban]

That would be another good write up idea, replacing the VR.

 

[chengny]

But, come to think of it, it's very possible the fusible link saved the alternator too. The fusible link actually brings power in the back door of the fuse block right? And the alternator is actually out the front door of the fuse block, or vice versa as an example.

Possible but, when exposed to reverse polarity, the diodes short out instantly (milliseconds) - way before the F/L has time to heat up and melt.

 

[HotRodPC]

But, come to think of it, it's very possible the fusible link saved the alternator too. The fusible link actually brings power in the back door of the fuse block right? And the alternator is actually out the front door of the fuse block, or vice versa as an example.

Possible but, when exposed to reverse polarity, the diodes short out instantly (milliseconds) - way before the F/L has time to heat up and melt.

True.
If you haven't got it fixed yet, I thinks it gonna be 14gu fusible link you'll want to replace that one with. Rule of Thumb is, you want go down 2 gu sizes for a FS wire.So if that wire was 10gu, then 12, then to 14gu is your 2 steps down.

 

[GreaseDog]

I've also popped an ignition module doing that, though I think that might have been a derby truck, so it's possible it was direct wired with no fuse at all.

 

[guywitheyebrows]

i know this i an old thread but i totally did the same thing, after a 4 hour road trip in someone else's f150 [not enough truck] after having bought a new battery after having had my old one stolen by a tweaker relative and my starter is direct wired to a botton floating around in the cab, so: ignition module, 14gu fusible link ( i watched those wires [what i believe are those wires anyway, with a fuse holder type connector] fry and the copper is melted together), alternator (unless i can get a voltage regulator and swap it out myself). did i miss anything? the fuse.....i guess fuse block, the fuse thing with all the fuses in it, seems to be not burned out.
due to the instructions i was originally given by a lazy brother, who has built these trucks from parts before but wont come hold the flashlight and give lessons, i swapped the chip under the distributor cap, and i got nothing. the dristributor cap itself has been swapped recently, but i cannot tell if i have spark at the wires because i have no helper and less than zero knowledge of wth is going on aside from 'lefty loosey righty tighty' and i mess that up too sometimes. any help will be apreciated

 

[1987 GMC Jimmy]

When you say chip under the distributor cap, can you be more specific? The big things under there are the rotor, pickup coil, and the ignition control module, which it sounds like what you've already replaced. The best way to test for spark without a helper is with a remote starter switch that you can hook directly to the battery and starter and an inline spark tester that goes between the plug boot and plug. It's just a light that flashes when you're getting spark. Both are readily available at pretty much any parts store. I'd hold off on the ignition control module until you fix the fusible link, which it sounds like you definitely need, and then see if you get spark. I wouldn't worry about the fuse block until you get the new fusible link done, and as far as the voltage regulator goes, I'd probe alternator output directly behind the alternator to see if it's too high or too low before you remove it and crack it open to replace the VR. In summation, I'd start with your burned fusible link, and slowly work your way from there if it needs more attention because it's not guaranteed that you'll need anything beyond the fusible link.