[john31s]

I'm trying to run a battery disconnect switch under the dash on my 70 Lemans. Where would the best place to pass through the firewall be? I plan on having the two wires run along to of the drivers side inner fender under the hood to keep them away from heat and the steering column but I don't see an easy way to get through the firewall.

I figured I'd consult this forum before I drilled a hole in my firewall.

[steve]

i am assuming you will be passing large gauge wire through the firewall for the switch. you will have to make a pretty good sized hole. have you considered coming through the floor ? i would say anywhere away from pedal movement and steering column movement would be ok....which means maybe passenger side ?

[john31s]

Originally Posted by steve

i am assuming you will be passing large gauge wire through the firewall for the switch. you will have to make a pretty good sized hole. have you considered coming through the floor ? i would say anywhere away from pedal movement and steering column movement would be ok....which means maybe passenger side ?

That seems like more trouble than it is worth. The battery and starter are on the driver's side. I'd also like to be able to reach the switch from the driver's seat.

[mrennie]

I wanted to run #4 wires through the firewall for my sound system but didn't want to drill an obvious hole. I looked at the assembly manual and saw there was a fairly large hole for cars with A/C where the vacuum and control wires went through, so I drilled the proper sized opening in the correct spot and ran my wires through the proper A/C grommet after drilling the grommet holes for the OD of the wire.

Maybe this would work for you?

[Blued and Painted]

run an ignition or fuel pump Kill switch?

[Bob Dillon]

Originally Posted by Blued and Painted

run an ignition or fuel pump Kill switch?

Ditto. Not that I know F-all about electrical issues, but it seems to me you're introducing a lot of resistance into the vehicle with unfused long, large gauge wires, and then there's the issue of live wires in the cockpit, both from safety and possible collision standpoints.

I just installed a large, bladed cut-off switch at the negative terminal on the battery. Works fine, turns off everything instantly. Here's one example, there are many others. I got mine at a local RV store and they had a pretty decent selection.

http://tinyurl.com/p98pan5

[ta man]

My question is what you are trying to accomplish?

[john31s]

Originally Posted by ta man

My question is what you are trying to accomplish?

Run a battery disconnect to de energize the car when parked. It has some electrical gremlins and a drain somewhere that kills the battery if left overnight. I currently run a disconnect on the batter but I would prefer it be in the car.

[steve]

there really isnt an issue with running a few lengths of good cable for that. i would consider the floor under your seat (near the frame rail) some of the disconnects can be mounted with only the key/switch part coming through the hole. OR maybe the glove box would be a trick solution.

[Blued and Painted]

Battery drain diagnosis.
Disconnect the battery. Hook a test light or volt meter between ground post and ground cable. The test light will light brightly if a 12 volt drain exists. A very dim light or low voltage reading if its a radio memory drain. Wont normally kill a good battery.

Now pull fuses until 12v drain or light goes out to determine which circuit has the fault or drain. A/C circuit normally has an in-line fuse under the hood. IF 12v drain still exists, disconnect control wires at alternator then the big hot post of alternator. The light should go out. This could mean a shorted diode inside the alternator. BUT keep in mind there are fuse links for the headlight switch and horn relay wired into the big hot post of alternator.

[steve]

Originally Posted by Blued and Painted

Battery drain diagnosis.
Disconnect the battery. Hook a test light or volt meter between ground post and ground cable. The test light will light brightly if a 12 volt drain exists. A very dim light or low voltage reading if its a radio memory drain. Wont normally kill a good battery.

Now pull fuses until 12v drain or light goes out to determine which circuit has the fault or drain. A/C circuit normally has an in-line fuse under the hood. IF 12v drain still exists, disconnect control wires at alternator then the big hot post of alternator. The light should go out. This could mean a shorted diode inside the alternator. BUT keep in mind there are fuse links for the headlight switch and horn relay wired into the big hot post of alternator.

Yo. Sage advice.

[mrennie]

Originally Posted by Blued and Painted

Battery drain diagnosis.
Disconnect the battery. Hook a test light or volt meter between ground post and ground cable. The test light will light brightly if a 12 volt drain exists. A very dim light or low voltage reading if its a radio memory drain. Wont normally kill a good battery.

Now pull fuses until 12v drain or light goes out to determine which circuit has the fault or drain. A/C circuit normally has an in-line fuse under the hood. IF 12v drain still exists, disconnect control wires at alternator then the big hot post of alternator. The light should go out. This could mean a shorted diode inside the alternator. BUT keep in mind there are fuse links for the headlight switch and horn relay wired into the big hot post of alternator.

This guy knows his stuff. Great tech advice.

[grivera]

Originally Posted by Blued and Painted

Battery drain diagnosis.
Disconnect the battery. Hook a test light or volt meter between ground post and ground cable. The test light will light brightly if a 12 volt drain exists. A very dim light or low voltage reading if its a radio memory drain. Wont normally kill a good battery.

Now pull fuses until 12v drain or light goes out to determine which circuit has the fault or drain. A/C circuit normally has an in-line fuse under the hood. IF 12v drain still exists, disconnect control wires at alternator then the big hot post of alternator. The light should go out. This could mean a shorted diode inside the alternator. BUT keep in mind there are fuse links for the headlight switch and horn relay wired into the big hot post of alternator.

I am experiencing same issue as OP and tried this test. With a voltmeter I got 12.64 volts!

[newtoponcho]

When I do a parasitic draw test I use the amp setting on the meter. I believe anything over .050 amps needs to be repaired. Most electronics, radio memory etc will typically draw .035 amps max. Hth.

[lust4speed]

You're just asking for future trouble bringing in a large cable in to the passenger compartment. As mentioned, longer runs equal more resistance, and longer runs gives more places for the wire to contact ground and start way too much excitement. Either fix the problem so there is no drain, or stick with disconnecting the cable at the battery.

We were a little dyslectic and pulled all the fuses and put one at a time back in the last time a friend needed to find a drain. Drain showed to be just under a half amp with everything turned off, and was enough so car wouldn't start the next morning. Somewhat of a shock when we traced it down to the cigarette lighter. Discharge was present even with the element removed, and this was a standard unit and not the one with a light. Disconnected the wire and things went to zero. Goofy thing looked perfect and we couldn't see any problem, and ohm meter confirmed a weak ground. Had to be something with the insulating material from the center conductor to the case. Anyway, don't discount anything when looking for the problem.