308 battery draw, here we go again

OK so clearly I am cursed regarding the battery on the 308.

After my long and arduous “is it the alternator? No it’s the damn idiot light not exciting” charging problem, I got the car home. Drove it some, let it sit about a month, drove it fine, let it sit another month while it rained... and the battery was dead.

I recharged the battery and it took a charge very quickly and easily restarted, so it seems there’s a draw somewhere now? Some details:

-had Birdman fuse blocks put in
-changed some window switches
-bought a replacement (missing) cig lighter but it’s just sitting in the socket, not pushed in
-buddy messed with wiring on replacement antenna
-aftermarket radio very weird, occasionally turned on by itself when driving and while sitting in running car

Went back a couple days later, started right up. Waited 12 more days, dead.

So my question is, are there easy, obvious draws on the 308 I should look at? Is there an incorrect way to shut off the car where the key is in a draw position (this happens on 63-7 Corvettes)? The interior light is just a little manual switch and was off. Steering column stalks?

I’m wondering if I’m doing something when I turn the car off that other rookies do. Or, is there a common gremlin to check?

I feel like that bizarre radio is causing issues but I don’t know Jack. Ideas?

 

Here is a battery drain I discovered: 1977 308, small red door light that comes on when you open the door, it’s the light in the sill of the door facing backwards when open. I have a wire that is loose so when I close the door a certain way it stays on. You can’t tell from the inside if it’s on. You can tell from the outside when the door is closed only at night. You can see a red glow when the door is closed.


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I'd have the the radio circuit checked. In my owners manual for my 78 308 GTS there is a separate page for the radio wiring diagram. Start there. Radios are never supposed to turn on by themselves!

Also, does your antenna operate like the original (switch spring loaded-up/center/down) or does the antenna come on when the radio is turned on?

 

It’s set up to come on with the radio. The switch just wouldn’t work.

 

I will check this... thank you.

 

I replaced my (dead) mirror switch with a brand-new unit; within 24 hours, my brand-new battery was dead. As I don't need to adjust them anyway, i put the old unit bad in. Parasite draw gone. I could troubleshoot further, but really not that interested.

Grab a meter, find the bad amp flow, and start the circuit tracing.... I'd start with the radio and antenna.

 

If you have a VOM with an Amp (current) selection, disconnect the radio fuse (it may be inline),and see if there is current flow to the radio with the car OFF.
Doug

 

To expand a bit, I suggest:

With the ignition key off, remove the ground cable from the battery and connect a multimeter that has a 10Amp capability(most do) in series with the ground cable (one MM probe attached to the cable, one attached to the battery terminal). OR - you can do this easier using the negative Quick disconnect but the battery cable is a more positive (NPI) way of performing the test


Now all elec power is going through the MM and you can read the current draw. With the ignition off, the meter will show the draw in MilliAmps (hopefully it isn't in Amps!). There should be a slight draw for the clock but no other current draw. I do not know how many mAmps the clock draws but I wouldn't think it would be more than 15-20 mAmps. In any case, start pulling fuses until you find what fuse(es) are causing the power draw and, therefore, what piece of gear is responsible.

Does the car have an aftermarket alarm? If so, then I'd bet that's the problem. The first thing to do with an aftermarket alarm is to get rid of it!

 

^^ This
First thing I did when my 85 Euro arrived was remove the aftermarket alarm.

 

Mike 996 has the best way of checking it for a drain with a meter. If you don't have a multi meter you can use a test light by disconnecting the ground cable and hook the test light in series between the neg cable and the neg battery post. If your test light is lit you have a drain. Then remove 1 fuse at a time to find which circuit the drain is on. The test light will go out or get dimmer when you find a drain. The only problem is if you have a intermediate drain it will be harder to find if its not happening at the time of checking.

 

Definitely remember - check amps in series, volts in parallel.

 

As I look at the labels on the original fuse boxes, there doesn’t seem to be a radio fuse. (Pre Birdman)

 

FWIW, one thing that pulling fuses WON"T do is find any draw that a PO may have created by connecting an aftermarket item directly to the battery or to the fuse block/wiring at a point in the circuit before the power would run through the fuse. Usually such devices will (hopefully) have their own in-line fuse but where it might be located...no telling!

 

My aftermarket radio (c.1985), uses the same power source the Blaupunkt did, which is unknown to me,as I just wired it up to that hot wire.

There are two fused wires that came with the radio: main power and some memory circuit that draws power all the time, so i put a little inline switch under the radio that i can turn off when i am not driving the car. That memory circuit will drain the battery in 2-3 weeks. I should probably put a modern radio in...

Doug

 

Gathering as much info here as possible but I just have to believe the weird radio is the culprit. It’s an interesting looking CD player/radio that disappears when not on and opens itself up when on. I was going to just roll with it as I’m not sure if the dash was mucked with making it hard to retrofit a “correct” Blaupunkt and it seemed to be working until it decided to just come on at will and maybe cause me these headaches.

 

Look for an under dash inline fuse and remove the fuse....See if the problem continues.
Doug

 

Ok, found where the fuse is marked on the original fuse box, but now that I have the Birdman fuse boxes in, they aren’t marked. Is there a find a fuse for dummies method for identifying it? Kinda wish I hadn’t made that upgrade right about now.

 

Ok while trying to eliminate stuff, I see a hole in the rearward facing drivers door jamb where a light might have been. Is this where the one you dealt with was?

 

My original fuse marking were on a (two) plate(s) on the inside of the fuse panel cover, NOT on the cheesy original fuse blocks.
That hole is your door pic is not for the light, the light is on the rear latch jamb of the door, nut the hinge jamb.

If your plates are missing, turn the radio on and one at a time, remove and replace fuses until the radio stops working.

If I had my car here, i would take pic of the fuses location plates, but it isn't here right now. You DO ahve wiring diagram, also. Did you check the manual for fuse location?

Doug

 

@Ferraritalian it’s on the other side of the door. Image Unavailable, Please Login


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Fuse location is going to be the same weather OEM blocks or Birdman blocks.

 

Not like this?


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You had plastic covers on your fuse blocks?
My car didn't. It had the metal tags glued to the inside of the upholstered panel cover. It was that way in 1984 when i bought the car.

You can see why i replaced them.
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Yes, that’s how mine came. Were mine added on?

Actually, all this has reminded me of a pic I took the night we got the car delivered, duh...
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Tim, thank you for the photo!