8 replies to this topic

[dixielou01]

does anyone know what will cause 12 volts to constantly pull from battery when key is in off position. I disconnect the ground from the battery and put a meter between the terminal and the post, to my understanding it should read 0 but I read -12.2  I have pulled all fuses and relays yet it is still pulling any suggestions?

[Bench Racer]

Does this current drain occure with the battery on/off switch in the on position or the off position?

Which wiring diagram did you use when installing your battery on/off switch or which wiring diagram did the installer use.

[Johnny D]

How about, is this a regular street car or a race car ?

 

J~

[dixielou01]

I just got this car 3 days ago and it is factory, so I don't have a on off switch but after trying everything everyone has suggested I am planning to install a kill switch so it don't drain every battery I get. at this point I am at a loss.

[Bench Racer]

There is a main fuse box (9 fuses) under the hood passengers side ??? and there is a fuse box (10 fuses) under the dash, drivers side.

Seems as tho you should be able when it's dark outside or in a garage have the battery cable connector finger loose and gently touch the battery post and with a current draw you should see a slight blue spark. Start in the fuse box and pull one fuse at a time and check for the little spark. If you have spark, put fuse back in. When no spark, your well on you way to finding the issue. I have used this process with vehicles that have a computer and it works.

[PRFGDWRNCH]

Measure the current, not the voltage. To protect your ammeter, first try putting a test lamp where you were putting the voltmeter. If the test light illuminates you have a draw that will be higher than the scale of some meters. Nearly full voltage will be indicated on a DVOM even with a very low draw. The computor has a keep alive continuous draw. Sometimes there is a minor draw from the altenator. You should see less than 50 mA draw. 

[dixielou01]

I tried the alternator and that didn't change the draw....but I may not have had my meter on the right setting so I will check this and try again

[davew]

Digital clock, Radio preset memory, any add on electrical items.

 

All will draw 12 volts, the important measurement is how many amps.

 

Dave

[Alberto]

does anyone know what will cause 12 volts to constantly pull from battery when key is in off position. I disconnect the ground from the battery and put a meter between the terminal and the post, to my understanding it should read 0 but I read -12.2  I have pulled all fuses and relays yet it is still pulling any suggestions?

 

 

Just to rule out the not-so-obvious....

 

Friend of mine had the same issue.  He had just bought the Miata and wasn't very familiar with it.  Long story short - turns out he wasn't turning the key ALL the way back to the off position. He was able to pull the key out at the #1 position (which powers on the electricals) and thought that was as far back as it went.  I got in and cranked it one position further.