How To Tell if Amp is drawing power when car is off

[zoltman1991]

Here is my situation: I recently had a sound system upgrade. I had a CXA400.1 with LC2i. This was swapped out for CXA1200.1/LC2i. They switched power cables to 4awg. I don't think there is a reason they would've touched the remote wire. Anyway, two days after, the battery died. Car still turned on, but couldn't turn over ignition. I noticed the amp/LC2i lights were on while car was off.

I believe my remote acc. wire was installed improperly and the amp was remaining on over night with car off.

If the amp/LC2i is drawing power with car off, the lights will be on, correct?
These lights should be off.

Now, when the car is off, the amp/LC2i lights are off. Does this mean I've fixed the issue?

How can I confirm with a multimeter.

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[metalheadjoe 10+ year member]

The most definitive way is to disconnect the components in question and see if the battery still drains.

If you suspect the remote connection, measure voltage at the remote terminal with the car off. As you stated, if this was the problem the amp power led would be lit up.

 

[zoltman1991]

The most definitive way is to disconnect the components in question and see if the battery still drains.

If you suspect the remote connection, measure voltage at the remote terminal with the car off. As you stated, if this was the problem the amp power led would be lit up.

So do I do (multimeter leads) positive to remote, then negative to ground? It should read absolute 0 right.

 

[metalheadjoe 10+ year member]

If you have a clamp meter you clamp around the remote and power wire together. If not a clamp you connect one lead to power wire and one lead to power on amp. You are allowing the electricity to go through your meter so you can measure it.

Both should be very close to zero.

 

[zoltman1991]

If you have a clamp meter you clamp around the remote and power wire together. If not a clamp you connect one lead to power wire and one lead to power on amp. You are allowing the electricity to go through your meter so you can measure it.

Both should be very close to zero.

Ok so to confirm. With car off.

Multimeter reads 9-10 at power/ground read.
Reads 0 at remote and ground.

With car on:
Remote/ground show 9-10.

This is the way it should be right? The power/ground will always read voltage because the power cable is always an active cable from battery.

 

[metalheadjoe 10+ year member]

Ok so to confirm. With car off.

Multimeter reads 9-10 at power/ground read.
Reads 0 at remote and ground.

With car on:
Remote/ground show 9-10.

This is the way it should be right? The power/ground will always read voltage because the power cable is always an active cable from battery.

Correct.

 

[zoltman1991]

Correct.

 

[Mitchell Fosgate III]

There is still power in the radio. Internal amplifier in the radio. Even when turned off. The radio is connected to external power amplifier. Now cannot be turned off, even when engine is turned off. It should die off automatically. If it doesn't it's not going to drain your car battery because the ignition switch is a switch that controls the electric or power to the amplifier. No power should go into the amplifier then. At engine turn-off. How can you check. At the terminals of the input for car amplifiers and output for radios. Speaker level inputs and pre-amp level outputs. Connections at these points with the multi-meter. Reading should be down to zero volts after it cools down.