Pulled on star and info fuse too…

 

0.16 milliampere = 0.00016 ampere

 

Where are you measuring the amperage?Where exactly did you attach the 2 leads? Just curious at this point. I should check mine.

 

1 Leave + lead on hummer attached to battery.
2. attach black on multimeter to battery ( will have to pull off hummer lead off)
3 attch red on multi to the black hummer lead. May have to pull the nut forward to get connection flowing on hummer negative lead.

 

Vax1op369 The safest and best way to measure parasitic draw is to connect a 1ohm 10Watt resistor in series with the 0V battery lead and measure the voltage across it, 1mV = 1mA.

It's safer because should something inadvertently operate, like a fuel pump, head lights or even cranking, it won't destroy your test meter, just the resistor maybe. It's also very accurate, and a 1Ohm 1% 10Watt costs around $1 dollar or thereabouts.

Multimeters tend not to be too accurate with small currents, I have a Fluke 87, a Fluke Scopemeter and a couple of budget meters and they all disagree with each other on low current, however with the resistor they closely agree.

MixManSC is quite right, it takes time for the ECU's to go quiet, for example the EVAP system small leak test can continue for up to 40mins with the ignition off.

According to GM Bulletin 2010-02-20_232547 (attached) the recommended maximum drain is 30mA but as to the accuracy of this document I can't say, my 05 struggles to get 38mA

hummerz correctly highlights that 0.16mA is tiny, you'd generate more current with two wires stuck in a potato.

You didn't mention if your Air Suspension was working or not?

It is possible for a fault ECU to cause a drain, there are two fuses HVAC/ECAS (under hood) and 4WD (left dash) pulling these should do the same as unplugging.

Keep us posted.

 

Appreciate the detailed response, & also thank you everyone who has also commented. The air sus I have always heard it kick on when I start the car, can hear it standing outside. Technically not sure if it is working. How would i k ow if its working? my H2 has the 2 inch lift button on the dash. When I press that nothing still happens. If the draw is extremely low what would cause the battery to be dead? First battery died. This battery also died a few times. Good cal on the hvac ecas i ran a diagnostic test and it gave yellow or red on that option. Will have to look at the fuses.

 

Re “Air Sus”

finall's comments on springs and connectors are very valid, one can only assume that you air bags are holding their pressure whilst disconnected?

Those connectors are IP (Ingress Protected) rated, so effectively waterproof but only when mated. Hopefully you only disconnected them momentarily and didn't drive around with them unmated, if you did you might consider flushing them out with a quick drying IPA spray cleaner.

The compressors only run when the engine is running, so when you start you'll hear the Air Suspension relay operate and also the two air-bag inlet valves intermittently whilst the AS ECU adjusts the ride height. If there is a problem with the AS Unit you will see the message "SERVICE AIR SUSPENSION"

BTW it's a sophisticated electronic system and will only run normally when conditions are right, however be careful ! If the battery is reconnected with the AS Unit unplugged the BCM will assume there is no Air-Ride system fitted. To make sure it's recognized, disconnect the battery, plug-in the AS Unit and then reconnect.

The 2" lift is the extended ride-height function which works as follows:-


Ride Height Switch

Extended ride height is used to increase vehicle ground clearance. When the ERH switch is activated the vehicle will raise 2 inches at the rear. The extended ride height will only occur if vehicle speed is less than 64 km/h (40 mph) with all doors closed the engine running. When the switch is activated the switch LED will flash while the vehicle is transitioning to extended ride height. When the vehicle reaches extended ride height switch LED will be on continuously. The vehicle will return to normal height when the switch is activated again and the switch LED will go OFF. The vehicle will automatically return to normal height if vehicle speed increases over 64 km/h (40 mph) and the switch LED will turn OFF.

Re Battery
Your "0.16" figure seems erroneous, I'll wager you've inadvertently blew your multimeter's fuse because if you'll notice the mA range says "200mA MAX FUSED"

The 200mA will have been exceeded the moment you connected your multimeter in circuit (for the reasons I mentioned before) at the very least unplug your Red probe and put into the DC10A hole on the left, but as I said before be careful, even 10A can be exceeded momentarily. Better to go and buy that 1 Ohm 10watt power resistor and measure the volts across it (1mV = 1mA "simples")

To measure parasitic draw, you'll need to keep the doors shut (door lights) key out, then disconnect the battery -ve terminal, connect in the 1 Ohm resistor and then connect your multimeter across it set on DC mV (NOT AMPS)

You should see some fluctuations in current which may take some time to settle down as MixManSC says and eventually you should read the parasitic draw.
Pulling fuses under the hood is easy, however the cabin fuse panel is more difficult as you'll have to open the drivers door. So it's not such as simple exercise to do.

​​​​​​​Hope this helps...

 

Only thing I can add is before plugging the suspension compressor in would be to first visually check if there are coil springs in the rear. If the compressor has been unplugged then it is very likely the air springs have been removed and replaced with coil springs. If that is the case then I'd suggest not plugging it back in (but maybe wrap the plug ends in tape to keep them clean.

 

Good call, I remember now there are coils back there on both sides. Makes much more sense now. Thx man

 

If the connectors were unsealed and hanging loose, they may have become corroded and possibly causing some drain.