Power Draw

[davery]

So I took the dash apart removed the radio, added a USB port and re-arranged some gauges and now I have a power draw. Where should I start with the voltmeter? Should I test each circuit at the fuse?

[aj81spider]

I have the same problem (about 750 mA draw when the car is off), but have a battery disconnect so I've been lazy about debugging it. I just disconnect the battery when the car isn't running. When I get to the garage, hopefully soon, what I plan to do is:

> Pull all the fuses out and see if I still have too much current. I expect that the current will be 0. If it's not then I'll have to find which unfused circuit is causing the problem. That will be more problematic - so I'm assuming that's not the case.

> Put each fuse back in alone and record how much current each one adds to the mix.

> Trace the circuit of any fuse that adds any significant (more than a couple of mA) current.

With the battery disconnect this should be pretty quick and easy. I just unscrew it so it's disconnected, then bridge it with the meter. The meter should be set to current sensing mode, which on mine also requires the leads to be moved to a different connector.

An alternate way to do it would be to remove each fuse and bridge the contacts with the meter. That will tell you how much current is going through that circuit.

[davery]

I have the same problem (about 750 mA draw when the car is off), but have a battery disconnect so I've been lazy about debugging it. I just disconnect the battery when the car isn't running. When I get to the garage, hopefully soon, what I plan to do is:

> Pull all the fuses out and see if I still have too much current. I expect that the current will be 0. If it's not then I'll have to find which unfused circuit is causing the problem. That will be more problematic - so I'm assuming that's not the case.

> Put each fuse back in alone and record how much current each one adds to the mix.

> Trace the circuit of any fuse that adds any significant (more than a couple of mA) current.

With the battery disconnect this should be pretty quick and easy. I just unscrew it so it's disconnected, then bridge it with the meter. The meter should be set to current sensing mode, which on mine also requires the leads to be moved to a different connector.

An alternate way to do it would be to remove each fuse and bridge the contacts with the meter. That will tell you how much current is going through that circuit.

I also installed s battery disconnect. I forgot to switch it off Sunday night and by Wed it almost didn't start. I will probably just test each fuse circuit separately and then see where I'm at.

[scrapironchef]

USB jacks can draw power all the time, even when no devices are plugged in. The 12>5 voltage converter is always on and depending on the quality may draw substantial power.

[TimpanogosSlim]

USB jacks can draw power all the time, even when no devices are plugged in. The 12>5 voltage converter is always on and depending on the quality may draw substantial power.

Yeah, that would be my presumption if the usb jack isn't on a switched power source.

Since it's so easy to do with bullet fuse terminals, i vote for testing each circuit by removing the fuse and bridging the terminals with a multimeter set to measure current.

[davery]

USB jacks can draw power all the time, even when no devices are plugged in. The 12>5 voltage converter is always on and depending on the quality may draw substantial power.

I installed the USB port using the OEM cig lighter connection. I didn't realize the cig lighter was on an "always on" circuit until I installed the USB port. I have since connected the USB to a switched circuit.