Strange Electrical Issue

[athawk11]

I recently reinstalled my speedometer and thermostat cables.  While shifting and moving stuff around, I think I made a mistake.

After my test drive for the speedo function, I pulled the hand brake and saw a spark.  I shut off the engine and inspected under the dash and couldn't see any issues.  I thought the sunlight may have played a trick on my eyes.  

I started it back up, released the brake, and pulled it again....then poof, smoke under the hood and dash.  I shut it off and pulled the key.  The wire from my start solenoid/switch fried all the way from the solenoid to the ammeter.  Initially, I figured I had moved that wire around enough to get it pinched in the hand brake rachet assembly.

I replaced the wire, making sure it was clear of the hand brake.  When I reconnect the battery, I get a spark, as if I have a short.

To eliminate problems, I bi-passed the ammeter and wired the battery directly to the ignition switch.  No spark when I connected the battery, and the Jeep started right up.  Checked and double checked all the accessories, ignition switch, light switch for bad or pinched wires.  I hooked it back up through the ammeter and I get the spark at the battery.  I'm at a loss.

Can you fry an ammeter?  What am I missing?

This is a new harness and everything functioned fine before I messed with my speedo and thermostat cables.

Tim

[athawk11]

I found this old post by F Bill.

Could this be my problem?
 ï¿½
http://www.thecj2apage.com/forums/topic11560&OB=ASC.html

This is the original ammeter and the insulators were a bit rugged when I put the ammeter back in.

Tim

[calvinhunt]

athawk11,
  I troubleshot an airplane charging system once in my past and found it to be the ammeter.  I don't recall that it was fried, may have been, just that it was defective.  A new ammeter fixed the problem.  So, your problem may be the ammeter internally or it could be the insulation breakdown as indicated in your link.  I think you're on the right track.

[Gunslinger]

I had a similar problem with my ammeter, except it was due to the hot wires contacting the frame that holds the ammeter in place.  The frame should have an insulator between the wire and the frame if thats missing it'll spark.

[athawk11]

UPDATE:  I started to remove my ammeter and discovered the ammeter retaining bracket had been completely welded to the dash.  Not good.

I followed the instructions that F Bill described in his post, right down to the trimmed down pen caps and old bucket, used as new insulators for the ammeter and bracket.  The electrical system is back to functioning perfectly.

Hopefully, I'm the only idiot in the room that didn't know the importance of insulating the ammeter electrical connection posts from all possible metal contact, other than the wires.  If my failures can help others to take care and be diligent in this part of your restorations and repairs, then I will feel good that I saved you from watching your hard work go up in smoke...literally.    

I want to thank F Bill for the post I mentioned above.

Have a good night.

Tim

[ventport]

What are thermostat cables?

[athawk11]

Hey Ventport.

The thermostat cable is really just the wire that goes from the temp gauge to the head.  I just call stuff 'cables' if they do not carry an electrical current.   ie: the speedometer cable, the hand brake cable.  Kind of goofy I guess, because I do call them 'battery cables'.

Tim

[ventport]

Got it, thanks now it all makes sense.