Slow parasitic drain (let's try this again)

[TorqueEffect]

I tried asking this before but didn't get anywhere.

I have a slow parasitic draw, and I have traced it to the Headlight circuit. Basically I have to pull the fuse when driving in the daytime, and only put it in when driving at night, so I don't end up with a dead battery when I have to go to work.

I have not been able to find a straight answer, the headlights work just fine, low and high beams, so I can't see why it would be a short, because a short would cause my lights not to work.

I would figure if the relay was sticking they would be on all the time.
Now I don't hear any kinda defined click of a relay when the headlights come on, only when the parking lights come on do I hear a relay click. Is this the same relay?

Which relay is exactly the one for the headlights? is it the one mounted on the fender behind the drivers side headlight?

[bravekozak]

88/89 had no relays. 90 and later had two separate relays. One for the Parking lights and the other for the headlights.
For a slow parasitic drain, get a multimeter, put it between the positive battery terminal and measure the draw amps.(doors shut, Key out of ignition, dome light and cargo light shut off) Then disconnect the ECU, measure the draw again. There must be a point when there is no draw. Pull radio fuse & recheck, Disconnect dash clock. What else? If it still there in milliamps, have someone begin to pull fuses while you watch the meter.
You should be able to find out what's causing it. I don't have a parasitic ECU. I have no idea what it draws. Good luck.


The headlamp relay is the one to the right of the cooling fan relay behind the left headlamp.
Which fuse do you pull? TAIL?

[TorqueEffect]

88/89 had no relays. 90 and later had two separate relays. One for the Parking lights and the other for the headlights.
For a slow parasitic drain, get a multimeter, put it between the positive battery terminal and measure the draw amps.(doors shut, Key out of ignition, dome light and cargo light shut off) Then disconnect the ECU, measure the draw again. There must be a point when there is no draw. Pull radio fuse & recheck, Disconnect dash clock. What else? If it still there in milliamps, have someone begin to pull fuses while you watch the meter.
You should be able to find out what's causing it. I don't have a parasitic ECU. I have no idea what it draws. Good luck.

The headlamp relay is the one to the right of the cooling fan relay behind the left headlamp.
Which fuse do you pull? TAIL?

I already did the parasitic draw test like you described. I pulled the Head fuse under the hood, and that's when the amps dropped to zero on the multimeter. (I didn't need to unhook the ECU)

It is a 91' I don't even know which one is the cooling fan relay. Only relay I see is the one right out in plain side mounted on the fender next to the coolant overflow tank.

[FestYboy]

i'll look on alldata and get back to you

[bravekozak]

Headlamp relay colors (from HEAD) = R, R, R/BK, W
Parking lamp relay colors (from MAIN) = W, W, R/BK, R/Y

You should have disconnected your ECA for the test. There is a splice in the white wire between the headlamp relay and the headlamp switch going to the parasitic ECA.

You also really need an EVTM. Then you would have seen this.

It's either your relay, headlamp switch or ECA.
Your mission is to find out which one!
Good luck Mr. Phelps.

[TorqueEffect]

Thank you. I really do need a EVTM. Have tried two different headlight switches, so it is either the relay, our eca. Hopefully it's the relay.

Sent from my SPH-M950 using Tapatalk

[FestYboy]

ok, from what i'm getting, unless the relay is stuck in the on position (which would mean headlights on all the time), it CAN'T be the ECA (ECA feed ONLY occurs when the headlamp relay is activated and is used to bump the idle for load compensation). the only other 2 options are Connector 101 and Splice 123.

I would lean tward C101 as the culprit as splices are not typicaly a spot for corrosion. to test for this, do the draw test again with everything in place and start disconnecting from the headlamp switch BACKWARD to the Head fuse (switch, relay, C101, Fuse). when you loose the draw, that's the issue. the reason i'm leaning tward C101 is this: there's likely a ground in that connector that is connected by corrosion to the power from the head fuse. that will cause a slow draw without melting anything.

[bravekozak]

Another thing I have to research!
I have to find out what the RPM increase is for headlights.
I only installed one idle up for A/C and P/S. I just noticed that the wire to the ECA comes from the headlight switch in an '89.
Maybe I just won't drive at night anymore. Or, maybe get a bigger alternator.

[FestYboy]

i've only ever seen a 100 rpm increase (if any). the point of load comp is to keep the rpms where they are, reguardless of the load (at idle)

[TorqueEffect]

ok, from what i'm getting, unless the relay is stuck in the on position (which would mean headlights on all the time), it CAN'T be the ECA (ECA feed ONLY occurs when the headlamp relay is activated and is used to bump the idle for load compensation). the only other 2 options are Connector 101 and Splice 123.

I would lean tward C101 as the culprit as splices are not typicaly a spot for corrosion. to test for this, do the draw test again with everything in place and start disconnecting from the headlamp switch BACKWARD to the Head fuse (switch, relay, C101, Fuse). when you loose the draw, that's the issue. the reason i'm leaning tward C101 is this: there's likely a ground in that connector that is connected by corrosion to the power from the head fuse. that will cause a slow draw without melting anything.

What is the C101 and where is it exactly located at?

Also may not be related, but it might be, or just probably a normal quirk. Seems like everything is not being provided enough power when the headlights are on, blower motor slows down when on full blast, and probably just a stereo quirk, but when the volume is cranked up and there is lots of bass, then screen on it dims slightly to the beat of the song, also seems to make the idle bounce just a hair I mean the needle bounces very very very slightly on the tach. Of course all this mainly happens at idle, or when the clutch is in and the engine slows down to idle.

[FestYboy]

What is the C101 and where is it exactly located at?

Also may not be related, but it might be, or just probably a normal quirk. Seems like everything is not being provided enough power when the headlights are on, blower motor slows down when on full blast, and probably just a stereo quirk, but when the volume is cranked up and there is lots of bass, then screen on it dims slightly to the beat of the song, also seems to make the idle bounce just a hair I mean the needle bounces very very very slightly on the tach. Of course all this mainly happens at idle, or when the clutch is in and the engine slows down to idle.

follow the load side of the HEAD fuse to a harness connector, that's C101. it's likely near the headlamp relay behind or below the battery. i didn't pull the location diagrams because there's only ONE connection between the fuse and relay.

as for the dimming lights, check your belt tention FIRST then verify charging voltage with and without loads. if the charging voltage dips below 13.4 with the loads on at idle, your regulator has taken a dump, or since you're in Ohio, you have corroded ground connections. clean ALL of them and retest.

[crazyrog17]

My first guess would be alternator. I haven't had to replace mine yet, but it takes a LOT to make my headlights dim at idle. The fan on 3, headlights, rear defrost and the volume at or above 35/40 (500W sub+100W radio), but it's just too ridiculously loud to listen to for a few minutes anyways.

I've seen alternators crap out because they're overtaxed, but usually it's just kaput. As mentioned above, the vreg is probably going out... or perhaps the battery has a dead cell it's trying hard to charge?

[TorqueEffect]

Battery is only a year old, and has a 3 year warranty, it has been doing this before, and after I bought the battery.

And I used one of our charging system testers from autozone, and it found nothing wrong with either battery or alternator. Although it bogs down the engine heavily for about a second when I run the charging system test, it passes giving a ok for both Diodes, and regulator. corroded grounds are probably a good place to start with this, also a very slow IAC might be it as well? But it is too damn cold to do anything right now. lol

[FestYboy]

do yourself a favor and monitor the charging voltage durring the test with another DVOM. also, you may want to just monitor the voltage WITHOUT the tester... and look at your AC voltage. high AC voltage is an indication of a diode failure or poor battery.

[1990new]

Here is a link to a site that does a good job of fully explaining the procedure to test for parasitic drain on your battery.
http://testmeterpro.com/parasitic-dr...-a-multimeter/