battery charger backwards

[jrsavoie]

My son-in-law hooked up the battery charger backwards on his 95 gas Tahoe. It turns over but won't start. where should we start?

 

[diesel4me]

in the fuse box..

Not sure on late model GM's,but many vehicles have a reverse polarity protection fuse or diode in the fuse box in case this happens while jump starting or installing a battery..thats where I'd look first..its possible to charge a battery "backwards",and now the positive post will actually be the negative..might need a new battery now too..

 

[jrsavoie]

from what I gathered he was in a hurry for work. Hooked the charger up, hit boost. hit the key and sparks flew but he doesn't know from where. They said they checked fuses but I doubt they had a tester. I forgot to ask. I'm just assuming now that I think about it that they checked them visualy.

 

[Leper]

It should have blown one of the main fuses. Worst case scenario... put your nose close to the ecm and see if you smell some fried electronics.

 

[goldwing2000]

Funny story: one time I put a charger on backwards to a battery that was completely dead and it actually put a reverse charge on it.
I had to kill it completely again and re-charge it the right way.

But yeah... either a fuse or a diode. There might be something in the owner's manual or service manual (you DO have a service manual, right?)

 

[89GMCSuburban]

Does anything else not work in the truck? Like lights, windows, radio etc.? If so, check the fusible links off the starter. Your best option to start tracing the wiring is from the starter...so I'd start there first. Check all fuses if all the stuff inside works, ECM fuse being blown DEFINITELY won't let it turn over.

 

[jrsavoie]

Does anything else not work in the truck? Like lights, windows, radio etc.? If so, check the fusible links off the starter. Your best option to start tracing the wiring is from the starter...so I'd start there first. Check all fuses if all the stuff inside works, ECM fuse being blown DEFINITELY won't let it turn over.

Turns over but won't start. lights & radio are working

 

[goldwing2000]

... ECM fuse being blown DEFINITELY won't let it turn over.

Unless '94 is different than '89, that may not be true. My buddy blew the ECM1 fuse on his Blazer and it just killed the fuel system. It still cranked fine and everything worked normally (other than the fuel pump).

 

[89GMCSuburban]

Turn over means start. Cranking is something else.....

 

[goldwing2000]

Turn over means start. Cranking is something else.....

Start means start.

Turn Over = Cranking, as in the crankshaft is turning over whether or not the spark plugs are firing. As the very first (and 7th) post says, "It turns over but won't start"

If an engine won't turn over, then it won't spin. Either because the starter is not engaging or the engine is locked up.

 

[jrsavoie]

Start means start.

Turn Over = Cranking, as in the crankshaft is turning over whether or not the spark plugs are firing. As the very first (and 7th) post says, "It turns over but won't start"

If an engine won't turn over, then it won't spin. Either because the starter is not engaging or the engine is locked up.

Might all depend on where your from.Though I thought that was a universal terminology. I'm closer to Michigan.
Thanks for all the advice. I'll let you know how things progress.