I'm having the same problem. All fuses both under hood and inside of car register as good. However, I have to Jumpstart my 1990 Honda Accord EX every time I start it. Complete battery loss if I turn it off. I've done lots of work on it, just want to find the source of the problem.

 

You will need to find the source of your current draw, because any faulty component can cause the battery to drain.

Search for The BEST Way TO Perform a Parasitic Draw Test on youtube for a good video.

Hopefully you can find the fuse drawing current, then you will have to narrow down what component using that fuse is causing the problem.

Your 1990 accord doesn't have the systems like newer cars, so you don't have the networked systems that need to go to sleep like modern vehicles.

 

OK - read everything above, have eis 395 amp probe etc; have Fluke 88 DMM - narrowed the drain to underhood fuse 15 as above & then narrowed to inside fuse #7 - about 150mA drain above the "normal' 50-or-so" which my CD manual says is for door MICU, Combo switch ICU & Gauge ICU & Immobilizer - do not have a Nav system

all the door locks work& the remote works - & individually working the ***** causes only a momentary amp increase & then stabilizes

update - just did overnite test with fuse 7 removed = NO drain; found process in manual for getting DTC on the system - ordered MPCS (SCS) 07PAZ-001010A test jumper tool from ebay

useful benchmark : "Check the parasitic draw at the battery while shifting into the sleep mode; amperage should change from about 200 mA (awake) to less than 35 mA (sleep) in less than 40 seconds."

- fyi that process is here
https://www.haccord.org/b_can_system...hds_-1502.html
https://www.haccord.org/sleep_and_wa...test-1503.html

MICS (Driver's and Passenger's MICU) Self-diagnostic Function ( )
http://honda.automotive-manuals.com/...000000691.HTML

1. is there a way to individually isolate/test each door lock switch without removing all the door panels? (- apparently not ) and if they all work normally could one of 'em be causing the drain?
2. what else could be a likely cause in the other above control units??
3. yes, also tried disconnecting alternator ideas - no joy

problem began about 2 months ago

many thanks to redbull1 for the above helpful explanation

update - did the DTC diagnostics - found b1278 code = headlite switch ON malfunction - cleared the code - no obvious problems with headlite switch or combo switch - afik everything works like it should

meanwhile - tested the new Interstate 51R battery i got from costco - label on it says 650 CCA - it would only do 450 on load test - returned it & installed a Grp 59 everstart maxx 600 CCA from walmart - so far so good - car can sit 3-4 days & still be at 12.55v & starts (altho it cranks a bit slow) - parasite drain is in the "OK" range now ~ < 50mA per Uni-T amp clamp & 22mA per Fluke 88

 

I actually had this problem. My story is that I bought a 2005 honda accord from a dealer. Months later it started having this problem where at least once a month, or sometimes more, I couldn't turn the car on. Boosting it worked after driving it for 30 minutes to recharge the battery a little. But after 3 or 4 boosts, since the problem was regular, it would drain the battery to the point where I would have to charge it. I found a good mechanic who welcomed the challenge. He would even charge it for free for me since it was occurring so often. He couldn't figure it out either. It wasn't until I remembered a time when the radio would turn on by itself out of nowhere and then shut itself off mystery. More on the radio:: it worked only the first time that I used it in the car and after that it never turned on. So i got the idea that it was the radio. They removed the radio relay and boom, problem solved. I had the car for another two years after that and never had the battery issue again. This problem wasn't as simple as checking the fuse to see what was loading it since it was an intermittent problem. These problems can be a nightmare to fix. Hope that helps someone.

 

I see that it has been a few years since you posted this. I'm new to the board and just want you to know that it is still being put to use. That Redbull user REALLY had some USEFUL INFORMATION. I appreciate you following up with the dealership repairs and I will be diving into this problem father. When I removed that fuse (BACKUP) the drain went away.