Parasitic battery drain from BCM? (Please help)

[sandor]

I'm an idiot with electrical troubleshooting, but here goes...My 94 Q shows 4 amp drain with hood up, 2.1-1.1 with hood switch disconnected. The Electrical device circuit pulls .2a while the BCM pulls .8a, with both fuses out the drain is .1a. I think if I fixed the BCM draw, the .4 amp drain I'd still have is acceptable. (is that nornal?)

I have run the first 4 self diagnostics (FSM pages EL-71 through 87) on the Body Control Module with normal results. I wonder if the "sleep mode" isn't working- but after 30 seconds the drain does go down from 2.1 to 1.1. Other than installing a battery tender and plugging it in every day, any suggestions?

Thanks in advance.

Sandor

[Q45tech]

0.4 x24= 10 amp hours per day doesn't give you but 8 days..........never checked a 94 for parasitic draw but early Q are ~~0.12 120 ma............what is alternator drawing? No mods no auxillarty add on system?

[texasoil]

Sounds like a time delay relay is not opening per plan. Parasitic drain should not exceed about 0.03 amps.

The magic number is 'set' by at least 2 week sitting and have enough barrety left at 0 degF to start. A 0.2 amp drain will take out 4.8 amp-hr/day--enough to nearly empty the battery in 2 weeks. You need to use a good meter to get the milli-amp draw measurement correct.

[sandor]

Dennis, Thanks for the ideas. I spoke with Ty at T3 yesterday and he mentioned the same thing; I unplugged the CD changer and ABS relay with no effect. On the main fuse junction (large wires held to 120 fuse with bolts) the only lead with voltage drain is the middle one--is that the alternator?

The biggest draw is the BCM, I might install a toggle switch off the fuse but there is no way my wife would remember to use it! It does go into sleep mode after 30 seconds and the draw goes from 2.1 down to 1.1 amps. Could the LCU be the culprit?

[Q45tech]

I have seen alternators draw too much bias current, you will just have to disconnect and measure until you find the problem.

[sandor]

Update: Found problem! The glove box light switch was bad and drawing the load previously described. Hope this may help someone in the future. Light wasn't coming on and unplugging switch fixed it. Curent drain is now 46MA



Thanks everyone.

[goody90q45]

Good find. How did you go about isolating the problem?