Battery Discharge Issue 86 coupe
#1
02-02-2008, 04:53 PM
Battery Discharge Issue 86 coupe
I could use alittle help/advise here please. Battery has discharged when parked for several years. I'm only now attempting to trouble-shoot the problem as I continue to try to return the car to the road. I've read a couple threads on this subject already but the problems seemed to be unlike this one.
I tested each circuit by pulling the fuse and measuring current by sticking tester probes onto the fuse contacts. I used the courtesy/clock fuse as a control. With hood up and door open I measured 3.85 amps flow. Most other circuits measured zero flow as I think they should with key off.
The brake circuit (extreme upper left) measured .43 amps however. The emergency brake is off. Brake pedal not depressed. Is there any reason why current should be flowing here? If not (as I suspect) what is there in this circuit that could go bad?
The only other fuse location that gave me any reading other than zero was the one marked LCD. On this one, the tester jumped to .25 then rapidly dropped to zero (two seconds at most). This happend several times but not every time. I'm kinda thinking I'm touching something inside the fuse box that I don't mean to touch. The area I'm working in is confined and I don't have a great view of the fuse panel. Any ideas here?
This method seems like it should work to determine which circuit is shorting or behaving improperly. If I'm missing something...somebody please speak up.
Thanks for your consideration and time....NineBall
I tested each circuit by pulling the fuse and measuring current by sticking tester probes onto the fuse contacts. I used the courtesy/clock fuse as a control. With hood up and door open I measured 3.85 amps flow. Most other circuits measured zero flow as I think they should with key off.
The brake circuit (extreme upper left) measured .43 amps however. The emergency brake is off. Brake pedal not depressed. Is there any reason why current should be flowing here? If not (as I suspect) what is there in this circuit that could go bad?
The only other fuse location that gave me any reading other than zero was the one marked LCD. On this one, the tester jumped to .25 then rapidly dropped to zero (two seconds at most). This happend several times but not every time. I'm kinda thinking I'm touching something inside the fuse box that I don't mean to touch. The area I'm working in is confined and I don't have a great view of the fuse panel. Any ideas here?
This method seems like it should work to determine which circuit is shorting or behaving improperly. If I'm missing something...somebody please speak up.
Thanks for your consideration and time....NineBall
#2
02-02-2008, 07:58 PM
RE: Battery Discharge Issue 86 coupe
ORIGINAL: NineBall
I could use a little help/advise here please. Battery has discharged when parked for several years. I'm only now attempting to trouble-shoot the problem as I continue to try to return the car to the road. I've read a couple threads on this subject already but the problems seemed to be unlike this one.
I tested each circuit by pulling the fuse and measuring current by sticking tester probes onto the fuse contacts. I used the courtesy/clock fuse as a control. With hood up and door open I measured 3.85 amps flow. Most other circuits measured zero flow as I think they should with key off.
The brake circuit (extreme upper left) measured .43 amps however. The emergency brake is off. Brake pedal not depressed. Is there any reason why current should be flowing here? If not (as I suspect) what is there in this circuit that could go bad?
The only other fuse location that gave me any reading other than zero was the one marked LCD. On this one, the tester jumped to .25 then rapidly dropped to zero (two seconds at most). This happend several times but not every time. I'm kinda thinking I'm touching something inside the fuse box that I don't mean to touch. The area I'm working in is confined and I don't have a great view of the fuse panel. Any ideas here?
This method seems like it should work to determine which circuit is shorting or behaving improperly. If I'm missing something...somebody please speak up.
Thanks for your consideration and time....NineBall
I could use a little help/advise here please. Battery has discharged when parked for several years. I'm only now attempting to trouble-shoot the problem as I continue to try to return the car to the road. I've read a couple threads on this subject already but the problems seemed to be unlike this one.
I tested each circuit by pulling the fuse and measuring current by sticking tester probes onto the fuse contacts. I used the courtesy/clock fuse as a control. With hood up and door open I measured 3.85 amps flow. Most other circuits measured zero flow as I think they should with key off.
The brake circuit (extreme upper left) measured .43 amps however. The emergency brake is off. Brake pedal not depressed. Is there any reason why current should be flowing here? If not (as I suspect) what is there in this circuit that could go bad?
The only other fuse location that gave me any reading other than zero was the one marked LCD. On this one, the tester jumped to .25 then rapidly dropped to zero (two seconds at most). This happend several times but not every time. I'm kinda thinking I'm touching something inside the fuse box that I don't mean to touch. The area I'm working in is confined and I don't have a great view of the fuse panel. Any ideas here?
This method seems like it should work to determine which circuit is shorting or behaving improperly. If I'm missing something...somebody please speak up.
Thanks for your consideration and time....NineBall
.43 amps for the brake circuit ain't right. Full draw brakelights is gonna' be a lot more 'n' that. .43 PARTIAL draw? Mouse chewed the insulation on the brake circuit somewhere??? I've heard the mouse-chewin' gig before...
#3
02-03-2008, 03:26 PM
RE: Battery Discharge Issue 86 coupe
I been considering the chance of mice damage. So far I found some droppings but no obvious damage. The wires leading aft seem to be in plastic flex sheathing so unless they got into those, the wires should be OK up to their terminals.
I imagine a few of you got a laugh out of my earlier post. It seems the "brake" fuse doesn't have anything to do with brake lights. I attempted to check the brake light switch under the brake pedal. In doing so..I depressed the pedal with the fuse pulled and the brakelights came on properly. Ditto turn signals and emergency brake dash light. If that fuse is supposed to do what I originally thought it did...I got some BIG wiring problems.
To date..I haven't figured out what doesn't work with the "brake" fuse pulled. I'm just gonna let it sit awhile and see if the battery discharge stops with the fuse out.
I'm open to suggestions.... NineBall
I imagine a few of you got a laugh out of my earlier post. It seems the "brake" fuse doesn't have anything to do with brake lights. I attempted to check the brake light switch under the brake pedal. In doing so..I depressed the pedal with the fuse pulled and the brakelights came on properly. Ditto turn signals and emergency brake dash light. If that fuse is supposed to do what I originally thought it did...I got some BIG wiring problems.
To date..I haven't figured out what doesn't work with the "brake" fuse pulled. I'm just gonna let it sit awhile and see if the battery discharge stops with the fuse out.
I'm open to suggestions.... NineBall
#4
02-04-2008, 11:28 AM
RE: Battery Discharge Issue 86 coupe
OK..I let the car sit overnight with the "brake" fuse pulled. It fired up like a champ on first try. No noticeable battery drain. This is obviously the faulty circuit.
One thing has finally caught my attention as being in-operable with this fuse pulled. I have "anti lock" light warning on the dash. Put fuse in....light goes out. Remove fuse again...light comes back on.
What components on this circuit could be causing a .45 amp drain when car is left overnight? Is there a module that could go bad? A switch? Sensors? What is "anti lock" and how badly do I need it to drive the car?
One thing has finally caught my attention as being in-operable with this fuse pulled. I have "anti lock" light warning on the dash. Put fuse in....light goes out. Remove fuse again...light comes back on.
What components on this circuit could be causing a .45 amp drain when car is left overnight? Is there a module that could go bad? A switch? Sensors? What is "anti lock" and how badly do I need it to drive the car?
#5
02-05-2008, 02:48 AM
RE: Battery Discharge Issue 86 coupe
ORIGINAL: NineBall
OK..I let the car sit overnight with the "brake" fuse pulled. It fired up like a champ on first try. No noticeable battery drain. This is obviously the faulty circuit.
One thing has finally caught my attention as being in-operable with this fuse pulled. I have "anti lock" light warning on the dash. Put fuse in....light goes out. Remove fuse again...light comes back on.
What components on this circuit could be causing a .45 amp drain when car is left overnight? Is there a module that could go bad? A switch? Sensors? What is "anti lock" and how badly do I need it to drive the car?
OK..I let the car sit overnight with the "brake" fuse pulled. It fired up like a champ on first try. No noticeable battery drain. This is obviously the faulty circuit.
One thing has finally caught my attention as being in-operable with this fuse pulled. I have "anti lock" light warning on the dash. Put fuse in....light goes out. Remove fuse again...light comes back on.
What components on this circuit could be causing a .45 amp drain when car is left overnight? Is there a module that could go bad? A switch? Sensors? What is "anti lock" and how badly do I need it to drive the car?
I had a water problem once, on an old Jeep Cherokee with weather strippin' gone from the power window in the tailgate. Took forever to find that draw. And you could hear that 'cracklin' through the water at the connector.
Put the fuse in, with the motor off, and disconnect the driver's ABS sensor, at the wheel. Check for draw. Do the same with the passenger side.
Just a stab in dark................................
#6
02-09-2008, 04:34 PM
RE: Battery Discharge Issue 86 coupe
I finally located the ABS computer bits under the tray behind the driver's seat. Close inspection found some corrosion between two plug type fittings in this compartment. Cleaning with contact cleaner and soft wire brush seems to have solved the problem. The fuse is back in place. I'll wait overnight to see if battery suffers again.
#7
02-10-2008, 06:33 AM
RE: Battery Discharge Issue 86 coupe
ABS sensors have no voltage on them. They are magnetic pickups that generate an a/c voltage that the ABS module reads (frequency and amplitude) to determine if the car is moving and how fast. One thing to check also is your engine compartment lights might be staying on and running the battery down. Half an amp draw won't run the battery down overnight on a fully charged battery that is in good shape. I've had a couple of corvette's in the shop that have had the lights stay on. The work off mercury switches that activate when the hood changes position and sometimes they go bad.
#8
02-10-2008, 12:14 PM
RE: Battery Discharge Issue 86 coupe
Thanks Mech..
I appreciate the info on the ABS sensors. Fortunately I didn't mess with those things. I tried to trace the wires for a place to unplug them but both sensors seemed to lead into darkness under the engine and I was too lazy to put it on jacks for just that one task.
Left the car overnight with the "brake" fuse in place.Battery seems to have fared OK. I'll keep an eye on it.
I was concerned about those hood lights earlier. I stuck my head up there after closing the hood to check whether they stayed on or not. They were off . I assumed they stayed off (the way you assume your refridgerator light stays off).
Thanks again for the suggestions and help..........NineBall
I appreciate the info on the ABS sensors. Fortunately I didn't mess with those things. I tried to trace the wires for a place to unplug them but both sensors seemed to lead into darkness under the engine and I was too lazy to put it on jacks for just that one task.
Left the car overnight with the "brake" fuse in place.Battery seems to have fared OK. I'll keep an eye on it.
I was concerned about those hood lights earlier. I stuck my head up there after closing the hood to check whether they stayed on or not. They were off . I assumed they stayed off (the way you assume your refridgerator light stays off).
Thanks again for the suggestions and help..........NineBall
#9
02-16-2008, 11:30 AM
RE: Battery Discharge Issue 86 coupe
I had a battery drain on my '87.Posted a plea for help on the board and received many good replies and things to check. Finally had one to ask if I had the battery checked.It was only two years old, but had it checked anyway, just like I was advised, the battery was bad. You might try this if you haven't already.
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