I have a drain on my batter that I cannot find for the life of me. I have an 86 k5, but the 350sb is out of a 79 pickup. If i dont start the blazer for a day or two, the batter will be drained just enough to get a click from the starter. I'm wanting to hook up a battery disconnect so help stop this ( have looked at every possible place a drain could be coming from and have not found what is doing it). I bought a 2 pole kill switch rated at 300amps, and it said to cut the battery's negative cable in half, and hook the switch up to those two new ends. That doesn't seem right to me. Anyone got any ideas on how to wire this up so that i can flip the kill switch from in the cab and isolate teh battery from the rest of the electrical stuff . . . without burning anything up lol.

 

that seems right to me. I think the only way to hook it up inside the cab would be to run some 4ga cable from the ground cable inside to the switch then back to the battery

 

do you know how to use a volt meter to look for a drain?
if so pull fuses until the load goes away then you can usually find the source from there


to do it you unhook the positive cable from the battery, using a volt meter set to read amps. hook one lead to the cable and one lead to the battery. pull one fuse at a time until the amps drop now you know what circuit to look on

 

Just to make sure that we covered all the bases here, how old is the battery? Even if it's fairly new, you could have a dud which would lose it's charge even after 2 days.

 

also true. I had this problem with my interstate battery. It was only 10 months old but i found out it was bad

 

Most places will check the battery for free if you don't have a load tester.

Here's a kinda wacky idea.
Install your switch under the hood. Mount it someplace stable. Run a cable into the cab through the firewall. It's be ideal if you get get a switch that is spring loaded and normally closed so all you would have to do is release the tension on the cable to close the circuit. Kinda the reverse of a parking brake. If that makes any sense.

 

im actually a pretty proficient mechanic, but, this whole kill switch thing has got me running circles because there are so many different ways. i did the voltmeter way and found nothing. even tried pulling fuses in the dark hoping to see a spark. the only thing i can think of is that there is a short somehwere, possibly at the alternator. thanks for all the tips though guys, i do appreciate it. i didnt think the negative cable method would work because isnt it still getting grounded? its ground on the block and on the frame. unhooking the negative cable (which is what i do know if i know i wont drive it) has always worked to keep the batter from draining, but, i just dont know how much faith i have in this switch being hooked up to the negative. the batter is good, i get it checked everytime it goes dead, just to make sure. ill guess ill go ahead and try the negative cable method and hope it works. thanks everybody.

 

Mount the switch right behind the battery, thru the fender liner, placing the handle on the bottom side of the fender liner. This way you will not have to open the hood to use it. You should have enough ground cable to cut it and crimp new ends on it that will bolt to the switch. You will need to cut the smaller ground wire from the battery terminal. This is a very common problem on computer vehicles. Often a relay will not release until power is cut, and then the drain disappears. Even when everything is working as planned, the load from the computers and radio/clocks will drain a good battery over time.

 

well, i got her hooked up two weeks ago. i mounted the switch on the little metal panel below the steering column. i ran a cable from battery to the switch, and then from the switch to the headers. works great, no problems at all. was kind of iffy having that long of a battery cable, but i have had no electrical problems (or drains!) since hooking it up. thanks for all of the advice.