Electrical troublehooting

[MarkH]

Hello, i am trying to start my 1978 L82 Silver Anniversary after being in storage and restorationf or the last 3 years. Car was funning well at the time after engine mods and updates, but I when I put in a new battery, I crossed the cables and it would not turn over. I put it in storage without fixing it.
I just put in a new battery and - nothing. Dead. No lights, buzzer - anything. Any ideas where to begin troubleshooting? Do you think that crossing the cables fried anything?

 

[Peer81]

Fried anything or everything?
Begin by checking all the fuses, also the inline fuses that go to the starter. I don't think there is an easy way to check this (altho the only way is a very easy way). Get a nice voltage meter and start checking everything step by step, that is what I would do.

Greetings Peter

 

[LLC5]

Hello, i am trying to start my 1978 L82 Silver Anniversary after being in storage and restorationf or the last 3 years. Car was funning well at the time after engine mods and updates, but I when I put in a new battery, I crossed the cables and it would not turn over. I put it in storage without fixing it.
I just put in a new battery and - nothing. Dead. No lights, buzzer - anything. Any ideas where to begin troubleshooting? Do you think that crossing the cables fried anything?

You probably burned a fusible link. If I remember correctly on a '78 they are installed on the starter solenoid bolt that attaches the positive battery cable on the starter solenoid. Good luck with it.

 

[MarkH]

Thanks for your insights! I am guessing the fusible link is the culprit too and I went ahead and got some replacement parts and keeping my fingers crossed. If that doesnt fix it, then I'm thinking the alternator was fried.

 

[TimAT]

Odds are just the fusible link. And you are reasonably lucky-- GM started using a "Starter Extension Harness" about 1976(? maybe a little before) Just to the right of the distributor on the firewall is a 6 way connector- all the car runs thru that connector- THe other end goes to the starter terminals. Disconnect that and unhook it from the starter, you can replace the entire harness OR rebuild it on the bench. Also it's a good time to look at the connector terminals- any corrosion or burned contacts should be replaced.

 

[MarkH]

Odds are just the fusible link. And you are reasonably lucky-- GM started using a "Starter Extension Harness" about 1976(? maybe a little before) Just to the right of the distributor on the firewall is a 6 way connector- all the car runs thru that connector- THe other end goes to the starter terminals. Disconnect that and unhook it from the starter, you can replace the entire harness OR rebuild it on the bench. Also it's a good time to look at the connector terminals- any corrosion or burned contacts should be replaced.

That makes sense. Just ordered the harness from Eclkers ($77), and yep, they started in late '77 models.