yet another question.... - PeachParts Mercedes-Benz Forum

lyle_H · #1 10-15-2010, 10:40 AM

today after the first freeze of the year....batt dead..but alt putting out properly..went to the local napa in marfa, tx and had my alternator tested but said my battery was weak and he commented that i might have a draw on the battery

i told him i didnt think so...is there any quick check that i can do to make sure that i do not have a current draw???

lyle

Ivanerrol · #2 10-15-2010, 07:25 PM

After market audio or after market alarm?

Gilly · #3 10-15-2010, 08:00 PM

Ahhhhh, how about by testing the resting current draw maybe?

david s poole · #4 10-16-2010, 11:33 AM

take a test light and disconnect the ground cable from battery,now put test light between cable and battery ground--if light comes on you have a draw.remove fuses one by one until light goes out.now read fuse index to determine what is causing draw.

lyle_H · #5 10-16-2010, 12:42 PM

david,

when i connected the test light the light was bright, meaning draw from somewhere. in the 420sel fusebox circa 1987 there are two white fuses in the first row. when i removed the second one, the light dimmed but did NOT go out.

help....

Gilly · #6 10-16-2010, 03:43 PM

Make sure all the light sare out, doors are closed, and also check to make sure the trunk light goes out (open trunk and push down the trunk light switch)
Gilly

Ferdman · #7 10-16-2010, 04:07 PM

Lyle, consider having an assistant get in the trunk and verify the trunk light goes out when you close the lid. The switch may seem fine when you press the plunger, but if it isn't depressed far enough when the lid closes then the light stays on.

Benica · #8 10-16-2010, 07:08 PM

With the trunk open, I just use my finger and push on the locking latch until it folds back like it was locked. Lights out. When done, push the trunk open lock to release it then you can close the trunk.
Start pulling fuses until the light dims or goes out and continue until all lights are out. Fuses removed....now trace back for the problem.

lyle_H · #9 10-17-2010, 11:02 AM

ok giys and girls,

yesterday did the who battery recharge thing at AZ and found the battery good, therefore had a draw....bought a testlight and went thru the fusebox identifying the DRAW on #15 which amongst other things is for the trunk light, dome light, etc....9 different circuits according to the fuse designation

removed the 15 and killed the draw....might wire in a switch temporarily before ts....

do not have schematics for 1987 420sel so if anyone can lead me in the right direction to get them, it would be appreciated..

lyle in marfa, tx

RPM55 · #10 10-17-2010, 02:41 PM

Of the items powered by that fuse the most likely culprits would be the trunk light or the antenna motor circuit. Try removing the bulb from the trunk light and see if the draw goes away, if so you have found your problem. If not try unplugging the antenna motor. The other consumers on that fuse could cause a draw but from my experience that is not the case. Let us know how it goes.

Good luck, Robert

lyle_H · #11 10-18-2010, 05:04 AM

as i told everybody on my last post, i have taken fuse #15 out of the fusebox.

being as i work nights right now i will take the trunk light out in the morning and reinsert fuse to see if that circuit is indeed killing my battery

if so and i would agree that it probably is the culprit, because the antenna does not raise so either the motor is faulty or not connected because i currently do not have a radio connected....

i know im in the dark ages but don't laugh...

bottom line...i tend to agree with the trunk light scenario and am thankful to RPM55 for offering me the schematic...

further updates will come....