After four years, I have reached the point in the restoration where I installed the battery and cables today and start checking for any gremlins I may installed along with the new wiring harnesses and additional wiring for Vintage Air, SpeedHut gauges and an aftermarket radio.

Here's what I have... headlights, both low beam and high beam work properly and marker lights and parking lights come on with the switch. Tail lights however, are on constantly. I have no turn signals and no emergency flashers. Also, I have no brake lights. There is obvious feedback somewhere, as the battery sparks when the negative cable is attached.

Am I chasing a bad ground, or is this an issue with the turn signal or headlight switch? I'm betting on one of the switches.

As always, help is appreciated

 

I would not just jump to the switch. Are you sure the taillights are what is staying on? Make sure it is not the brake light circuit. Unplug the switch. Start with one thing at a time and check each circuit. If you have a bad ground at the taillights, you may also get dim light at the front markers with brake on. Headlight switch is likely OK. If brake light switch is on, 4 ways will not flash and front parking will light when 4 way is on.
Avoid the pain of just replacing the turn signal switch until you check circuit.
You have 2 circuits at taillights.

 

Pretty sure it's not brake lights, but will pull the plug on the b/l switch to eliminate that. Thanks.

 

The battery will spark as long as a positive goes to ground, as in your lights staying on.
Are you familiar with using test lights or voltage testers?
You can also pull fuses and see when taillights go out.

 

Lucky enough to have a master tech for a son-in-law... gonna go thru all procedures tomorrow. My expertise in electronic begins and ends with replacing the batteries in my tv remote.

 

I understand. Did the replacement harness come with connectors, or did you have to remove wires and install the new ones into the old connector? Maybe got a wire or 2 in the wrong place.

 

Primarily a factory harness. The Vintage Air harness runs independently and is powered with a direct connection to the battery. Gauges are powered from the "BATT" post in the fuse box, and the radio is assigned to the "ACC" terminal. There were a lot of feeds that were no longer used on the factory dash harness. The engine and front lamp harness are from American Autowire and were modified by them to use HEI ignition and an internally regulated alternator. The rear harness is the original one piece unit. We'll start with the fuses and work from there.