I was cleaning out the inside of my 7 today when I decided to try to get it to run so I can move it. I just bought the car, I know it ran before I bought it but I got it with a dead battery (wouldn't even hold a charge) I got another battery from another car and dropped it in when I connected the red terminal to the battery's + side and I started to touch the black terminal to the battery's - side when it started sparking and smoking like crazy... I looked down at the old battery and realized some joker painted the terminals the wrong color.

now nothing works.... how bad did I just screw my new car up?

 

Nothing works? No lights? Then check the 'fusible links' on the fender well near the battery.

Most stuff is bidirectional (like lights) , so it won't matter, but some things like the radio and the ignition 'ignitors' will blow when they're reverse biased. And the alternator could blow too, it has diodes. And you may have reversed the residual magnetism in the starter motor, the starter solenoid and the alternator. Maybe the starter motor and solenoid will reverse again when you hookup, but probably the alt is shot. Fortunately, alts are pretty cheap at the boneyard, or even the rebuilts at the auto store. If it's the 7 with external diodes and regulator you may be able to just replace them. Even if they're internal you may want to get the rebuild parts and do it yourself to avoid the heartbreak of having a moto-gang-rebuild fail on the road.

Check all the fuses, too.

B

 

You probably just blew the main fuseable link, hopefully. On the strut tower near the battery is the fuesable links. Theres 3 of them. One is marked main.

 

Are fusible links bidirectional?? If they are they wouldn't blow.

 

It will blow when you have a direct short, which will happen when you hook the batt backwards. Current will flow through the alt diodes straight to ground. Thats what messes the alt up.

 

Oh, ok. I will remember that.

 

yeah, one of the fusable links blew, actually shot the wire off of it

 

is this a part I can fix at AutoZone? the fusable link is blown and I dont want to straight-wire it due to I still dont really know what I'm doing with the FB (I come from a Honda, Mitsubishi, Toyota, and FWD Piston Mazda background)

 

Ignore that... I went down there and found one, I got a 30 amp hoping the heavier one would do the job but when I put it in and reconnected the battery the new one blew... any suggestions? Every wire that's in the open I've checked to make sure nothing is touching anything else. should I disconnect the alt?

 

Check all relays, fuses and wiring. It's possible that some smaller gauge wiring heated up enough to cause a permanent short. In that case you'll have to break out a multimeter and a schematic (sp) and start testing. My brother did that once on a '86 Taurus. Fried half the electrical system.

Your alt may be ok. Those are some beefy diodes in there.

Good luck.


Eh...an electrical system is for all intents and purposes an electrical system. Just 'cause it has a cool motor doesn't mean it's missing things. Think logically....

 

I've checked the fuses under the dash, are there any more fuse/relay panels I need to look at?

 

Well, I don't know where they put them all in an FB, but there are ignition, starter and light relays (I'm sure there are a few more that matter).

Typically under dash fuses are little ones for int. lights, radio, wipers, inst. cluster, etc.

 

well, I've checked everywhere I can think of... and six fusable links later I'm still no closer to having it fixed. I cannot seem to isolate the problem. even with the coils and alt unhooked. I think I've just toasted it...

 

there is a chance you burned the igniters, i have seen it happen before

 

Depending on which one you blew the fuseable links are like 40 amps, so that might explain why you blew a 30 amp fuseable link... The main one is 80, and the other two are 40.

~T.J.

 

Disconnect the heavy wire at the alt, replace the link again, and reconncet the battery. You probably fried the diode and now have a short to ground thru the alternator. If it doesnt blow this way, then your diodes are shorted. Any decent alt/generator repair shop should be able to supply the diodes at least, or fix it for you if you prefer.

 

Yea but TJ, just connecting the batt with nothing on shouldnt blow the link if nothing is on.

 

Very possible also, since theres diodes in there too. You might want to disconnect them as well to test this.

 

I've only seen 30a fusable links... but after the first two I made one just using regular automotive fuses for testing purposes

 

I connected my new battery backwards too. The fusible link blew so I stripped the insulator off that little bugger and twisted the two wires back together.

I reconnected the battery correctly, plugged the fusible link back in and started her up. I then went inside and got clean underwear!

 

 

ROFL yeah, I was about there myself.

Okay, I finally found the heavier fusable links at AutoZone but before I spend anymore on them I need to know how heavy to get each one of them.

Oh, I picked up some new OEM replacement coils and all I have to do is go pick up another alt. from the guy I got the car from.