I've got a short to ground somewhere in my '90 Civic EX. I pulled every fuse in the fuse box under the dash. I pulled the fuses and fusible links in the fuse box on the passenger side of the engine bay. I pulled the two fuses attached to the positive battery cable. None of these shut off the current flow!

My Hayne's manual does not have a wiring diagram for my car.

Are there circuits running on other fuses that I haven't yet found? If so, where would I find them?

One of the main lines off batt. + goes to the engine bay fuse box, then presumably through the big fusible link there. There is another big line from batt. +. Does that run straight to the starter solenoid?

Does anyone know of a diagram for this model online?

Thank you in advance for any help you can offer!

Dean

 

yes it runs to the starter.....what happen?did the car just have a short out of a blue moon?

 

Basically yes. It sat for a couple of weeks due to a bad radiator. The battery went flat. After charging the battery, I checked and got current flow between neg. batt. post and neg. batt. line. Nothing was on to draw current, so there should be a short to ground somewhere.

At least that would be my conclusion on my old, simple car. The only thing I know of that would draw current while "off" would be the stereo and clock, but I pulled the fuses for those circuits and current continued to flow.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dean2 &raquo;</TD></TR><TR><TD CLASS="quote">I've got a short to ground somewhere in my '90 Civic EX. I pulled every fuse in the fuse box under the dash. I pulled the fuses and fusible links in the fuse box on the passenger side of the engine bay. I pulled the two fuses attached to the positive battery cable. None of these shut off the current flow! </TD></TR></TABLE>


One trick to finding shorts is to put a lamp in place of the fuse; that limits the current. then you can watch it while you wiggle wires, disconnect various accessories, etc......

In your case you can put it in series with the battery cable. Further, you can get an idea of how much current the "short" draws; an 1134 taillight may glow, or be full brightness; if full, try an old sealed-beam headlamp.




Modified by rusted-CRX at 6:21 PM 4/4/2007

 

It's not drawing enough to light up my test light. My ammeter says it's about 150 mA, but the reading was very erratic. It would jump up and immediately fall off. That doesn't seem like much power.

 

did u check the battery ground to the frame?and there should be one from ur starter to. its kinda odd that this happend after u changed the battery. r the cables in good condition?

 

make sure your door is shut btw. if you have door mounted belts then it draws some current, its normal.

i recently thought I had a short. i checked until i found the horn/ brake fuse cuts power to the seatbelts(when a door is open). I was killing my battery by leaving my door open (domelight off)

sounds like you may have a problem somewhere. but i had to mention this, i thought it was kinda weird cause sometimes i would find a draw and somtimes nothing(door shut).

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dean2 &raquo;</TD></TR><TR><TD CLASS="quote">It's not drawing enough to light up my test light. My ammeter says it's about 150 mA, but the reading was very erratic. It would jump up and immediately fall off. That doesn't seem like much power. </TD></TR></TABLE>

That may not be a short. Some things will draw power even when "off"... such as a clock, radio memory, etc.

What you describe as "jump off & fall off" sounds like a capacitor charging.... What is the steady-state draw after that?

 

I've been closing the door. It probably is something simple I'm missing, though!

After jumping up, the ammeter falls basically to zero. I tried using a lower scale and blew the fuse on my meter, so I can't check just how close to zero. Would a capacitor give me a steady reading on the voltmeter?

Does the ECU draw power when the car's off and is it on a completely separate circuit not covered by the fuses I've checked?

I still haven't checked the wiring before the engine bay fuse box and before the starter. I'll check those when I head back out.

Thanks for everyone's help so far!

 

150ma isn't a short to ground. That amount of current should not kill your battery charge. It seems consistent with what would be considered normal. (BTW, there is a fuse inside the meter that is replaceable. It's typically a half amp or so and is the cylidrical snap in type most of the time). A capacitor will draw current until it is charged and then drop to zero. The amount of draw is dependant on the rating of the cap (the higher the microfarad rating, the higher the draw)

 

Thanks for all the help everyone. I'll leave it be. I'll be using the car now that the rad's fixed, so I'll know soon if there is something amiss.

My meter had a spare fuse, so I got it going again. I just need to remember to replace it in case I pull another boneheaded move like today. My other car's English, so the meter tends to come in handy.

Dean