Parasitic draw- Body and Cps Fuse's

[breakbredquick]

Alright, heres the deal any and all help would be appreciated. I got a 1990 riviera with a parasitic draw, so i bought a volt meter and tried to find it. I set the volt meter to 200mA and hooked it between the negative post and the negitive wire and it read 10.9 with doors closed and no lights on. Now obviously thats to much otherwise my battery wouldnt drain in less than 12 hours. So i start pulling fuses, and i pulled every one i could spot. It went down like this. There were two fuses drawing power, the CPS fuse (wich i would like to know what this fuse is/does?) was drawing 5.9 and dropd the volt meter down to 5 then i pulled the body fuse wich i also have no idea what this fuse is or even if they should be drawing power but this fuse was drawing 2.2. So with every fuse pulled the volt meter read 3.0 or right around there wich my understanding from my research is this number is still to high. So im lost what is my next step and can someone please tell me what these fuses do. I want to fix this problem not have to pull these two fuses every night.

[Mickey#1]

If your meter has a 10 amp setting I'd like to see you repeat the test on that setting.
Anything under .05 amps should not drain the battery overnight or even over several days. I believe 10.9 with the meter set to 200 milliamps is .0109 amps. Someone please correct me if I'm wrong.

[HotZ28]

I think .0109 mA would be ok for these cars. That is slightly more than 1/100 th amp draw. Have you tested the altenator for drain? If you have a bad diode in the rectifier bridge, it can short to ground, therefore, have a constant drain on the battery. BCM's can also be a suspect.


BTW, 1000 milliamps =1 Ampere, 1mA = 0.001A

[breakbredquick]

Originally Posted by Mickey#1

If your meter has a 10 amp setting I'd like to see you repeat the test on that setting.
Anything under .05 amps should not drain the battery overnight or even over several days. I believe 10.9 with the meter set to 200 milliamps is .0109 amps. Someone please correct me if I'm wrong.

K tried the 10a setting and got no results all zeros and this was after i changed the voltmeters fuse.

[breakbredquick]

Originally Posted by HotZ28

I think 0.109 mA would be ok for these cars. That is slightly more than 1/10 th amp draw. Have you tested the altenator for drain? If you have a bad diode in the rectifier bridge, it can short to ground, therefore, have a constant drain on the battery. BCM's can also be a suspect.


BTW, 1000 milliamps =1 Ampere, 1mA = 0.001A

im taking this as on the 200ma setting the numbers i got are not high enough! So i dont need a new BCM or a CPS? The alternator has been tested at advanced and passed all test. Ive been through 1 battery with this problem and the battery i have now is only about 2 months old bought new. I was hoping the CPS or BCM was my culprit for a quick fix but thats not looking to be the case. Im stumped guyz and have looked through every post about buick in general.

[HotZ28]

Do you have a volt meter in the IC? If so, what is it showing when engine is above 800 rpm? Does it stay steady and above 13v? Have you checked battery voltage after driving to see if it is 12.67v or above?

[Mickey#1]

Did you check the manual for the correct way to set the meter for 10 amps. Most of the meters I've seen you have to plug the meter lead into a different 'socket'.

I'm not sure if we can trust the 10.9 reading. When I did this test on my 89 Bonneville (same engine) the meter would read over 1 amp when first connected then drop to .01 amp after the chimes stopped & the ECM goes into power saving mode. That's about the same reading you have but it sounds like you blew a fuse.


HotZ28 - I think you did the math wrong. .oo1 x 10 would be .01

[HotZ28]

Thanks Mickey, quite frankly I didn’t do the math and that was the problem. I need to invest in a new set of drugstore reading glasses, so I can see where I put the (.) decimal .............0109 Anyway, if it is only 10.9 mA draw, that is nothing!

[breakbredquick]

Alright folks, here is what i did. Pulled all the fuses i mean all of them out of the three fuse boxes, one under the hood and one on each side of my console. Let the car sit over night with the fuses out, woke up put them back in and walla, no start dead battery again. So were the hell is my energy being lost at and how. Im so lost, could it be my starter, what could it be. I think i can cancel out the bcm and cps now, but im lost as to were to look next any help would be greatly appreciated

[52mercury]

I have had a parasitic draw on Buicks before. Check the( radio, internally ) and its associated circuit for the parasitic draw. It's a long shot,but it may resolve your issue!

[HotZ28]

Do you have auto climate control? If so, the blower control module is a direct feed (unfused) and can be a suspect here. In addition, the altenator and starter are both direct 12v from the battery. Disconnect one at a time and see what happens. Remember, always remove the negative (-) battery terminal first when working on the electrical system!