96 850 Testing for battery drain

Post by **DeadEric** » 03 Jun 2019, 22:43

I'd pull the glovebox bulb until you find a fix for it staying on. It's a known issue so take it out of the equation.

The only thing I can think of for a fuse to have a voltage drop of near battery voltage is if the fuse is blown. Power on one side, ground on the other and nothing connecting them...

You can verify they are blown, using the same check in the ohms setting. An OL reading would be blown. Keep in mind, fuse don't just blow. Something in the circuit had do draw more amperage than the fuse could let flow. But, I wouldn't go down that road until your draw is tackled. It's best to disturb as little as possible, so you don't temporarily "fix" the problem before you find it.

http://new.volvocars.com/ownersdocs/199 ... 50_613.htm

The manual says what the fuses are for but other things can be on the circuit too. Hopefully I'll have 5 minutes to check at work tomorrow.

Knowing the fuses that are "alive," you can go back to amperage check at the battery. Pull the low voltage fuses and check for an amperage drop. Do them one at a time and plug them back in after taking your reading. Check the meter after plugging them in to see if something powered up. Wait for it to go back to "normal" before pulling the next fuse. Sometimes things "wake up" when power is supplied and take a bit to "go back to sleep."

Hopefully only one fuse is keeping you above the golden .05 amps.

tardcart · Post by **tardcart** » 04 Jun 2019, 19:08

some times when diagnosing a problem I suspect muchaures by proxy syndrome. Leave your car alone and buy a battery.

Post by **Eddystone** » 04 Jun 2019, 21:48

tardcart wrote: ↑01 Jun 2019, 18:59 Its pretty hard to measure mA with a less than 200 dollar meter.

All other completely rational statements aside...let's not make statements like this.

Post by **Eddystone** » 04 Jun 2019, 22:04

DeadEric wrote: ↑03 Jun 2019, 22:43 I'd pull the glovebox bulb until you find a fix for it staying on. It's a known issue so take it out of the equation.

I LIKE that. Had my glovebox liner out to replace my blower motor, and battery has been too low to start a couple of times. Haven't troubleshooted yet, but that sounds likely to be my issue. It may be premature, but thanks very much for the hint!

DiggerDaz · Post by **DiggerDaz** » 19 Jul 2019, 22:15

I solved mine - there was a constant drain on the battery when fuse 15 was in circuit. Using an old fuse with wires soldered on, I put a DMM on a high current range in series with the 'test fuse' and went tracking. I found that the left side (passenger door in my RH drive car) door light was on all the time. You can't see this while the door is shut but a couple of crocodile clip jumper leads allowed me to have the lamp hanging out where it was visible while I operated the door.
Suspecting the door latch, I removed it and dusted it with compressed air before lubing it with WD40. Reassembled and open/shut door 50x - total cure!

Post by **MoVolvos** » 19 Jul 2019, 23:05

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The BEST Way TO Perform a Parasitic Draw Test?

96 850 Testing for battery drain

Re: 96 850 Testing for battery drain