79 Brave What broke?

[Shasta]

Accidentally hooked my battery up backwards. smelled smoke and disconnected it. reconnected it properly, but now it does not start. no dash lights or power to anything when I turn the key. looked at the wiring but could not find anything obvious. The first component past the battery is a solenoid. then there is a gang of electronic boxes that Dodge is famous for. Anybody have any ideas about what I should change first. This Rv is new to me, so I'm kinda in the dark about where to start looking or replacing.
Any help is greatly appreciated.

[MrTransistor]

Hi Shasta,

I wish I could advise you on the likely component to fail. Problem is, there’s no way to tell what the weakest link might be. All you can hope for is someone to respond that has been down this road.

I would start troubleshooting by first checking all of the fuses I could find for ones that are open (make a note). As a component fails inside one of the modules, there will likely be a very high current as the normal failure will result in a short of that component. This will blow the fuse ‘sort of’ protecting other units on the same circuit. Of course if more than one fuse is blown, there will be multiple component failures. But again, there is no way to know which would be prone to fail first.

If you can find detailed enough schematics, an electronics technician might be able to ohm out the individual boxes for the bad one. Another way is to connect an ohm meter to the output side of the fuse holder, get a good reading (which will be close to zero if the component shorted), then start disconnecting the individual components that are feed by that fuse. When you get to the bad one, the reading will jump up a little. If the fuse is rated for say 10 Amps. then the total load on that circuit will probable be no more than 5 Amps. At that, the normal resistance will be more than 2.5 Ohms. If you have a reading of say .2 Ohms and after disconnecting component X the resistance jumps to 3 Ohms, you can bet that that component is shorted and will have to be repaired or replaced.

The other scenario is an opened circuit caused by an opened wire or circuit board trace on a chassis component that controls the ignition switch signal to the rest of the vehicle. If your meter reading is 2.5 Ohms and you see no change at all when disconnecting component X, then I’d suspect that that component may have an open internal trace.

Either of these two failures will cause smoke so that symptom is of little use unless you know where the smoke came from.

Then you could get really lucky and hope that the design engineer used reverse polarity protection design on all the electronics and all you will need to do is replace the fuses and hit the switch.

I hope you get lucky cause this could get expensive. Good Luck!

[Shasta]

Thank you so much for these tips!
I was fishing for someone who had been down this road. Well, I'm off to work. It may take a couple 3 days for me to sort it out. hopefully I will get the magical response or find it before I'm out of money.

Do you have and old Bonnie or a new one. Either way, nice machine.
Thanks again.

[lakewoodpaul]

you might have a fusible link on the pos. side of your battery it will look like a wire in the harness.

[MrTransistor]

Hi Shasta,

It’s new (kind of), 2007. 18,000 miles in two years. I had a 1967 Bonne but had to sell it when I went to Nam (couldn’t stand to see it sit). Saw this one on the Triumph web site and just had to have it. So glad I did. Smoooooth!

Hi Paul,

Could be, but I was thinking if he smelled smoke it doesn’t seem like a fusible link. I’m not sure but I don’t think these give a burning smell when they open. I’ll need to check on that.

[MrTransistor]

I stand corrected.

From Catalog

NOTES about Fusible Links Only a serious short will cause a Fusible Link to burn–it disconnects a circuit from power just before the rest of the wiring in a circuit would be damaged. Momentary overloads will not burn out a Fusible Link–such as arcing a wrench between ground and an exposed terminal.

The insulation of the Fusible Link wire is soft and non-flammable, sometimes the conductor strands within will burn without noticeable damage to the insulation. A good test is to try stretching it. If it stretches like a rubber band then the wire within has burned out.

Keep them out of the cockpit! (When Fusible Links burn they often emit sparks and smoke.)

When installing the Fusible Links, the wire terminals should be crimped, then soldered, and then insulated with shrinkable tubing. (An on-board spare may be installed too.)
Learn more about Fusible Link wires in the “tech is made simple” book, from M.A.D.

[dirko]

Hi Ho Shasta: You have received good advice. The best way to determine where the problem lies is to just make voltage measurements starting at the battery. Then go to the solenoid, etc. etc. Somewhere you will find a place where there is voltage on one side and nothing on the other. I know this is really elementary, but it may not be obvious to someone not used to working with electrical circuits.

For example, if you get voltage on one side of the fusable link and nothing on the other side you have found the problem.

Good luck, Dirk

[Shasta]

Thank you all for your suggestions. I am gonna start at the first thing past the battery; some sort of battery isolator solenoid. I''ll check the wiring behind that as I change out this part. I'll get back to ya when I get it fixed or run into another wall.
Thanks again!