A parasitic drain test with confusing results
Thread Starter
TECH Resident
Joined: Jul 2007
Posts: 967
Likes: 53
From: Winter Haven FL
A parasitic drain test with confusing results Chasing a major battery drain and my results are confusing.
DC 5A setting:
Initial reading is 2.8 amps
After 1 minute it's .97 amps
After 10 minutes it's .91 amps
So I'm trying to find a massive drain, or multiple big drains.
I found 2 fuses that impact the reading, but they don't add up.
Pulling only fuse 4 (radio accy) drops the reading to .26 amps so it seems initially to be responsible for 2/3rds of the entire drain.
Pulling only fuse 7 (power accy) drops the reading to .00 with an occasional flutter to .01 Which means it's responsible for the entire drain.
With fuse 7 pulled but fuse 4 in place I should be seeing a huge drain still, but I'm not. That makes me think fuse 7 powers fuse 4, but the schematics don't show that.
I checked the schematics and fuse 4 only handles the power antenna and the monsoon amp (I don't have the external cd player). Fuse 7 is the alarm, trunk release, power mirror, radio and instrument cluster.
The common thing between the 2 fuses is the radio, but pulling fuse 17 (radio) had no effect at all. I would imagine a short in a radio circuit would be impacted by fuse 17 unless I'm missing something.
Tomorrow I'm going to pull the radio and see what happens, but I'm hoping someone can give me other things to check while I have everything apart.
DC 5A setting:
Initial reading is 2.8 amps
After 1 minute it's .97 amps
After 10 minutes it's .91 amps
So I'm trying to find a massive drain, or multiple big drains.
I found 2 fuses that impact the reading, but they don't add up.
Pulling only fuse 4 (radio accy) drops the reading to .26 amps so it seems initially to be responsible for 2/3rds of the entire drain.
Pulling only fuse 7 (power accy) drops the reading to .00 with an occasional flutter to .01 Which means it's responsible for the entire drain.
With fuse 7 pulled but fuse 4 in place I should be seeing a huge drain still, but I'm not. That makes me think fuse 7 powers fuse 4, but the schematics don't show that.
I checked the schematics and fuse 4 only handles the power antenna and the monsoon amp (I don't have the external cd player). Fuse 7 is the alarm, trunk release, power mirror, radio and instrument cluster.
The common thing between the 2 fuses is the radio, but pulling fuse 17 (radio) had no effect at all. I would imagine a short in a radio circuit would be impacted by fuse 17 unless I'm missing something.
Tomorrow I'm going to pull the radio and see what happens, but I'm hoping someone can give me other things to check while I have everything apart.
Thread Starter
TECH Resident
Joined: Jul 2007
Posts: 967
Likes: 53
From: Winter Haven FL
I got impatient and pulled the stereo lol
Without the stereo it was .02 amps. The factory stereo gave the same reading.
So something in the stereo is pulling power from fuse 7 and signaling the amp to stay on at fuse 4. There's a setting that uses sleep mode instead of powering off completely so I'll turn that off and retest. Maybe I'll get lucky and that'll fix the problem. If not then I'll just have to remember to pull fuse 7 when I park for the night.
Without the stereo it was .02 amps. The factory stereo gave the same reading.
So something in the stereo is pulling power from fuse 7 and signaling the amp to stay on at fuse 4. There's a setting that uses sleep mode instead of powering off completely so I'll turn that off and retest. Maybe I'll get lucky and that'll fix the problem. If not then I'll just have to remember to pull fuse 7 when I park for the night.
