Hey guys, I reversed the battery cables the other day when starting my truck and I think I fried a few things. I saw a puff of smoke come from either the starter relay (solenoid?) or regulator. I tried starting it for a few minutes before noticing the cables were reversed. Truck turned over fine with the cables reversed. After that the battery wont charge and the battery lights stays on. Truck runs fine and everything else seems to work except the radio (burnt out radio fuse on aftermarket radio). When I disconnect the positive the truck dies.

- Changed the regulator.
- Had the alternator tested; tested good.

What now? How to I go about checking my wiring? Could it be something to do with the green wire between my oil light and regulator? I just cut the fuseable links in half before leaving the shop today and the wires inside seemed fine in all of them. Fuses under the dash are fine also. I have a multi-meter and will sharpen the tips tonight and prepare for some troubleshooting tomorrow. Thanks for the help.

Regards,
Paul

 

What are you going to do now that you have cut all your fusible links? I am not sure that was a good move. But that is what usually smokes when the cables are reversed. Did you check the main fusible link right at the large battery terminal on the starter relay (solenoid)?.

Check your fuse box for power. The brake light circuit, the hazard circuit, the domelight circuit, the cigarette lighter circuit, etc. should have power all the time, even with the key off. If you do not have any power on these circuits, then you still have a main power problem out near the starter relay on the fender. There should be one or two large yellow wires heading from there to the firewall, those are the main power wires.

 

thanks for the quick reply. I was planning of running the wires straight without the fuseable links or whatever you guys recommend. Would the truck start and run fine if it was a main power issues? Headlights work

 

"I was planning of running the wires straight without the fuseable links"

I can say the same statement above with 3 words....
Destruction by Fire!

 

Agreed....the PO of Blue Ox did just that. Lots of melted wire insulation and compromised wire under her hood when I got her . First order of business was to replace all of the fusible links along with about a 1/4 mile of multiple gauges of wire.

 

I think the mystery puff of smoke you saw may have been a fusible link letting go. Several of them are tied into the system at the "upstream" post at the starter relay. As others have urged, don't just replace any fusible links with heavier wire. They are there for a reason, and it seems at least one gave its life to protect your truck from catching fire.

I'm surprised your alternator tested fine. I'm pretty sure hooking up the battery cables backwards will fry the internal diodes. Depending on the exact failure, you may still get some charging output, but the battery will quickly run down with the engine off. I wonder if they tested for that.

 

Oops, forgot a couple of important things:

1) On a vehicle with an alternator, don't disconnect the battery with the engine running. This causes a huge voltage spike that can damage the alternator, the regulator, or any other electronic components. On an older vehicle with a generator, you could do this for troubleshooting, but it's asking for trouble with an alternator.

2) When disconnecting the battery (engine off, as above), always unhook the ground cable first. When reconnecting, always do the ground cable last. Otherwise, if your wrench should slip and contact the fender or other metal, it will create a huge direct short to ground and a massive fireworks display, possibly including the dramatic grand finale of your truck burning to the ground.

And from the Useless Trivia Bureau, note I said "ground" cable, not "negative" cable. Not too many left on the road, but at one time a lot of vehicles were positive ground. If you unhook the "ground" cable first, you're always safe, no matter the vehicle. Not so on the rare occasion you'd be dealing with a positive ground vehicle.