Normal Parasitic Current Level

[diyrx300]

99 RX300 AWD with 120K

The car failed to start on the first attemp but did start on the second attemp with more cranks than usual. I checked the following:

Battery voltage -12.2V (engine off)

alternator output - 14.0 V. (engine on)

Parasitic current - 0.45 A (disconnect the battery cable from the Negative post and measure current between the post and the cable with all lights/doors/accessories off)

I thought the battery is dead after 6.5 years but also suspect there is an excessive parasitic drain.

Recharged the battery overnight using 2A slow charge. Still didn't hold charge for a couple of days. Went to the corner Advance Auto Parts' store and the clerk did a test and told me it's very very dead. Replaced the battery with Advance Auto Parts' Auto Craft Silver battery. Now because I am afraid the 0.45A parasitic current will drain the battery gradually if we don't drive it everyday, I have to disconnect the negative cable battery when we are not driving it! So I am having a 10mm box wrench with my key now!

Checked the fuse box, if I disconnect the DOME fuse, current drops to 0.22A. If I disconnect the SHORT fuse, current drops to 0.01A, which I think should be normal.

Does anyone know what's the factory spec for the parasitic current? Any idea which circuit connects to the above two fuses and which could be the culprit? Also when I connect the battery cable, I can always hear the A/C air flow control door unit is busy rotating. If I switch the mode from HEAD or HEAD/BODY to FOOT or FOOT/WINDSHIELD. The rotating noise went away. Wonder if this could be the source of the power leadk? All the accesories are OFF when the noise occurs immediately after I turn the keys to ON in the ignition switch.

Any experience with these symptoms are highly appreciated.

Thanks!

[diyrx300]

Just fixed the click noise under the passenger side dashboard by following the post by Tracilex Jun 10 2005, 05:06 PM - it's the A/C air flow control unit's copper contacts problem.

This also fixed the excessive current issue, it drops from 0.44A to 0.05-0.06 A after the fix. I guess the servo motor draws some juice from the battery even ignition switch is off due to unsecure copper contact in the DENSO control unit, which probably didn't enable the ECU to park the contact lead to fully "OFF" position even when the whole power system is OFF.

This is a DESIGN FLAW because all the copper contacts are pretty clean. They just lost the flexibility serving as a bended contact over time. Wonder why DENSO engineers never thought about puting someting more secure mechanism in there to make sure the contacts are good over years instead of five slim copper contacts.

Still wonder the official parasitic load level for 99 RX300. Anyone has EVER measured them??? My other 90 Mazda MX6 only has 0.01-0.02 A. I guess RX300 has many CPUs and memory chips...