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Reconnected battery with fuse mpx b and dome. Current readings at first was 4 amp then setteled to .5amp open either front door reading is .7 amp.open either rear door current reads1.5 amp . Tried disconnecting doors individually and still no lose of current .
Last edited by coltking; 04-13-15 at 05:37 PM.
Reason: update
So with all my testing that i have done i am thinking that the mpx body control unit is at fault.so i guess ill just leave the 2 fuses out for no and begin looking for a new bcu 89221-50090 if someone has one or knows where to obtsain please let let me know thanks on advance
My '98 LS400 has a similar problem. If I don't drive it for a few days, the battery hasn't enough charge to start it. It only has a small Odyssey PC680. Something is drawing current, don't know what... so.... I put a 20W solar panel on the back parcel shelf and a regulator in the boot that goes to the power cable on the amp that goes straight to the battery. I know its an unorthodox way to fix the problem but it worked. Its been like this for 12 months and battery never gone flat. (It doesn't even need direct sunlight to charge... just daylight)
My '98 LS400 has a similar problem. If I don't drive it for a few days, the battery hasn't enough charge to start it. It only has a small Odyssey PC680. Something is drawing current, don't know what... so.... I put a 20W solar panel on the back parcel shelf and a regulator in the boot that goes to the power cable on the amp that goes straight to the battery. I know its an unorthodox way to fix the problem but it worked. Its been like this for 12 months and battery never gone flat. (It doesn't even need direct sunlight to charge... just daylight)
My '98 LS400 has a similar problem. If I don't drive it for a few days, the battery hasn't enough charge to start it. It only has a small Odyssey PC680. Something is drawing current, don't know what... so.... I put a 20W solar panel on the back parcel shelf and a regulator in the boot that goes to the power cable on the amp that goes straight to the battery. I know its an unorthodox way to fix the problem but it worked. Its been like this for 12 months and battery never gone flat. (It doesn't even need direct sunlight to charge... just daylight)
I am looking at doing just this on my 1998.If car sits 8 days battery is dead.Same as before key mod pretty much.Previous owner also warned me about that.I was hoping to find the spot to tie into electric that was safe.
Do you get any funky volt readings having solar running while car is charging?Going straight to the battery is just what I was thinking,any spikes in power would be controlled by battery.Do pioneer stereo cars have an amp in trunk?
Do you know how much parasitic draw you had?I like the idea of a never dying from sitting battery.
I need to check mine,and also get a full charge in battery,only at 12.2 after 45 minutes at 1200 rpm and 13.3-13.4 volts.Alternator seems OK,14.4v on start up and 13.2-13.3 after several minutes and at idle.
When I get some diagnosing done if I cant find or fix it,I may be doing that same work around mod.My prime suspect is in the after market radio install.
Ive just done a ten watt on my rarely driven jeep,new battery and it holds a great full charge now always.
Looking at this 50 watt panel,looks like it would fit.Going overboard on it perhaps,but I only get MAYBE 2 hours direct light,very poor solar site here.Parasitic draw will give me lots more info on panel needs.
So found out a few things today
1-my test meter is not sensitive enough to read milliamps,its more for industrial uses....so couldnt do a parasitic drain test.
2-The little doodad volt meter that plugs into cig lighter is junk.Its within 0.1 tenths when car is running,but at rest reads as much as 1 volt less when at rest.Oh well,has a couple USB ports that might be useful.Only runs when cig lighter powered on when car is powered up,so it isnt a draw.
But I did find this...when you drive car the aftermarket radio turns on by itself and turns off when key off.Get in,starts by itself again. BUT,when you manually shut off radio,stop car then get in and start it again radio DOES NOT automatically start.So there is a live circuit,like on your instant on TV that is remaining powered if radio isnt manually turned off.
How much does this draw,dont know.Got a meter on order,should know in 4-6 days.
Nice start anyhow.All the youtuber mechanics saying 80% of current draw problems are after market radio's or alarms seem to know if what they speak.
Tested at 50 milliamp draw,radio on or turned off manually no change.So doesnt seem any unreasonable parasitic draw.Yet in 4 days from a fully charged battery 12.6-12.7 reading bouncing around,its 11.92 volts in 4 days.Started car but not as sprightly as a full battery.
Next stop to autozone to test my 11 month old 24F Interstate MagnaTronPlus battery,get load tested.Thats their best flooded lead acid battery.
Today when I was measuring the current to a bulb 12V 5W attached to the 10A fuse used for the MPX-B line of my 98 Celsior, I happened to find that there was a current draw of 11.2- 11.7mA at the MPX-B line after the bulb was removed. There was the voltage drop of that fuse and it was around 0.1mV and I needed to confirm it reversing the test leads. The left photo below shows there existed -0.1mV when the test leads were reversed. It showed +0.1mV when + and - leads were reversed.
By these, I thought there was a current draw always at the MPX-B line. So I removed the fuse and measured the actual current (the right photo). It was showing 11.6mA but it varied 11.2 to 11.7mA by my multimeter Fluke 8060A. Another thing I noticed was that there went about 600mA initially but waiting 15 seconds or so, it became 11mA+.
Anyway, my multimeter can find 11.6mA of parasitic drain current without removing the fuse. All I had to do was just attach the test leads to the top of the fuse and read the voltage.
Last edited by Yamae; 10-21-18 at 08:16 AM.
Reason: To identify the year
For comparison my 1997 LS400 has a rest current of 24,8mA. Alarm went off at about 11,82Volts. Batterie should be charged when less than 12,4Volts (75%).
Fastegg,got your message,thanks.I see you get much better solar radiation than I,I may be stuck using the 50 watt panel for that reason.
Members,I will update this thread going forward regarding the fastegg teaching on Lexus car solar he is passing to me and what I do regarding any solar on this car,im just not there.....yet.Im still in diagnosing modes,now battery I must clear as 'suspect' or not.
Took battery in today.No issues with car (alternator tested at 13.6,full load,at idle),but they could only say its 'iffy' and couldnt give a yes / no has it failed answer at this point and asked could they give me a loaner while they checked it for 2 days.Works for me.They were real nice,whole crew at the local Interstate place.
04-13-15, 08:24 AM
drain
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