Parasitic drain?

Adam Owner Arizona Posted   Latest  
Resolved
Electrical
2009 Honda Civic LX 1.8L (R18A1) 5-spd (SPCA) — 2HGFA16559H363730
Battery Dead
A/C Vented

Towed in. Dead battery. Cust says battery intermittently goes dead. Jumps it to start, can go days or weeks without going dead. The A/C also inop. Charge and test battery, 75 % capacity. Ck alt output to 80A, <1V AC. parasitic draw <500ma. Started and drove three times without incident. Found A/C low on charge. High pressure relief vented. Charged system. I noticed that the fans were erratically on and off. Wiring diagram shows that both fans are wired in series when A/C is on. Replaced both fans and two relays. Drove for two days and it sat over weekend. Returned to customer. Two weeks later, car is back. Same condition as original. Customer says it was fine for about ten days, Had to jump it 3 days ago, fine for three days. This morning had to jump it, and in several blocks, at a stop it vented the A/C again. Obvious that the A/C vents because the fans are not coming on, but the erratic drain when the fans aren't powered overnight? Any help appreciated.

0
David Mobile Technician
California
David
 

Adam, the max parasitic drain on that car is 50ma after the modules power down. Perhaps that was a typo on your part?

0
Ð Awarded
Nate Owner
California
Nate
 

You say parasitic draw is <500mA. I would expect that car should be < 40mA.

0
Ð Awarded
Adam Owner
Arizona
Adam
 

sloppy proofreading, sorry. It did vary. But the max was about 48ma, mostly saw 42-45. Need to put my glasses on when I type, I guess. Half an amp would have been a trigger. Never saw it less than 40, though.

0
Ð Awarded
Obie Technician
Washington
Obie
 

The fan control is obviously not working. The relays are module controlled. Work back to that issue and your draw may appear. Any model car can have modules damaged by key on jump starts. Customer jump starts make me wonder, especially if there is any arc evidence on the battery cables.

+1
Ð Awarded
Agree
Adam Owner
Arizona
Adam
 

Since the module only grounds, where is it getting power? Ignition switch/key is tight and checks ok. No power to any of the relays with key off.

0
Ð Awarded
Obie Technician
Washington
Obie
 

My post was poorly stated! My point was if the module can't supply ground at the correct time how can you be sure it is operating correctly in other ways? The cooling fan should work with engine temp. Does it work properly? Intermittent draws are sometimes hard to find. With another problem attack that one first.

0
Ð Awarded
Alejandro Technician
California
Alejandro
 

Check the relay for the a/c clutch. They used to get stuck on at all times. It would cause high, high side pressure and a dead battery.

+3
Ð Awarded
Agree
Alexander Diagnostician
New Jersey
Alexander
 

I agree on reference to the ac compressor relay. Check to see if the relays have a internal diode. If it does replace it. Because the diode can leak and create a lacht condition which will result in the parasitic draw

+1
Ð Awarded
Agree
Adam Owner
Arizona
Adam
 

Ding! Ding! Thank you all for your input. Second road test of the day. Returned to shop and found A/C clutch engaged. Tapping on the relay released it. Thanks much, guys!

+3
Ð Awarded
Thanks
Ted Owner
Texas
Ted
 

If you have an IR scanner, put vehicle in sleep mode with doors and hood open and do temp scan in am after sitting. This is the simplest way to identify intermittent draws. Without IR, you can use a meter with min/max recording and monitor likely circuits.

0
Ð Awarded
Sean Diagnostician
United Kingdom
Sean
 

The Bluetooth module is a common battery drain issue on these cars. Worth disconnecting to try.

0
Ð Awarded
Adam Owner
Arizona
Adam Resolution
 

A/C clutch relay!

+2
Resolution Ð Awarded
Agree
Helpful
Glenn Owner/Technician
Texas
Glenn
 

AC relay problem was very intermittent. Uusually all you had to do was shut it off with the clutch engaged and in some cases you could see it was still engaged. Or just try to turn it. Also after a short time it would be warmer than the other relays. Was the pressure relief valve replaced. It was my understanding that once they popped off they could release at a lower pressure.

0
Ð Awarded
Adam Owner
Arizona
Adam
 

Hi, Glenn As many times as I checked for drain and found none, it's hard for me to believe that a relay could be so whimsically intermittent. I guess the heating of the relay makes the contacts stick. Flattening the battery must cool the relay and open the contacts. When I found the clutch engaged, all it took was a light rap on the top of the relay to release the clutch. When it's 106 outside…

0
Ð Awarded