Electric problem Help Pls

[Classicman]

Tuesday I was working on my Chevy Super Cheyenne 400 BB and everything was fine and running great. Today I changed the heater core and I opened the switch to check the heater fan and there is no power. My battery is dead, no lights, no alarm , nothing electric work. the battery and alternator are new. I took my battery to Auto parts to charge the battery. PLS HELP!!!

[hamjet]

Hi, check to see if you broke the small wire comming from the + terminal to the junction block on the fender along side the battery. Maybee....

[VetteVet]

The small wire is the fusible link and if it is broken you will not have any power to the fuse panel or the key switch, providing that you have a 72 or older truck. The key switch feeds the fuse panel and the heater circuit which is fused in case of a short to ground. Most likely what you have done is left an interior light on or some other key off load.

When you get your battery back in, connect the positive cable and then tap the negative cable against the negative terminal and watch for a spark. If it's a small spark then go ahead and connect the cable and try to find the item that's drawing current from the battery.

[Classicman]

Thanks for you help . I have some bad news, my battery doesn't charge any more and almost brand new . 6 months old , and is the third that I been replacing on my truck . Any suggestion pls. I really don't know what is the problem . Thanks...

[Prematuregrey]

Use an OHM meter between the positive and negative terminals with the battery disconnected to find the draw. Make sure everything is off that has a switch and disconnect stuff or pull fuses until its open. I'm pretty sure these trucks don't have anything accessory wise that maintains voltage with the key off. As far as going through so many batteries, I would lean towards a bad voltage regulator overcharging the battery.

[motorcritter]

Check connections and wires- all of the relevant ones in the charging system. Check alternator output and regulator output- if you're still running OE style external regulator. Also, ground connections- the other half of the equation. Sounds time-consuming and painstaking- and it is. Cooking off three batteries in short order indicates something's not right in electron flow system. I had an experience recently getting the '70 C10 running to assess the engine condition- turned key: nothing! Lights worked, horn worked, no ignition. Turned out, somewhere along the path to my hands, the hot wire on the ignition with has been pulled out of the connector and reinstalled in a reversed position. The lock tab on the blade connector wouldn't hold it in position, it popped out and...
no juice flow. I was glad it was that simple, but most electrical faults I've found have been trifling things like that. Years as a Honda guy got me trained to look at the connections first- hot and ground- and it make it a lot less tedious.

[68gmsee]

Originally Posted by Classicman

Thanks for you help . I have some bad news, my battery doesn't charge any more and almost brand new . 6 months old , and is the third that I been replacing on my truck . Any suggestion pls. I really don't know what is the problem . Thanks...

How long a period between battery replacements?

If it's a short period of time, I'd be looking to get a different brand and/or looking at an alternator/regulator problem if everything else checks out as mentioned in above posts.