1990 Honda Prelude battery drain question.

[Bobthebeard]

Mentioned this a while ago, but the battery drain has worsened somewhat. Now flattening the battery over two days. Removing the 10 amp fuse marked 'clock' stops the drain. As far as I can tell, this fuse powers the keep alive circuit for the clock, the stereo and the 'auto box controller' whatever that is. Removing the fuse does not affect the auto box at all when driving. Only affected things are clock and stereo losing memory. If the fuse is replaced (ignition switch off) a relay can be heard clicking in somewhere in the bulkhead area and a multimeter shows a drain of almost half an amp! Have removed the fuse for now, but would like to sort the problem. Any ideas folks?

[twosmoke300]

Iirc these had a recall for a multiplex control unit fault . This could cause battery drain . Pm me your vin and I'll check if it needs it done or ask your local Honda dealer.

Otherwise look closely at anything non Honda . Radio , towbar , parking sensors etc.

[Bobthebeard]

Iirc these had a recall for a multiplex control unit fault . This could cause battery drain . Pm me your vin and I'll check if it needs it done or ask your local Honda dealer.

Otherwise look closely at anything non Honda . Radio , towbar , parking sensors etc.

Thanks! Only non Honda part is the stereo. No towbar or parking sensors etc. VIN number pm incoming.

[twosmoke300]

Is it the square headlight model . ?

[twosmoke300]

Just been thinking . Isn't the radio fuse also feeding the interior lights ? Worth checking glove box and boot lights etc. Half an amp is quite a drain

[Bobthebeard]

Is it the square headlight model . ?

This model.....

[Bobthebeard]

Just been thinking . Isn't the radio fuse also feeding the interior lights ? Worth checking glove box and boot lights etc. Half an amp is quite a drain

Interior lights/ glove box lights etc ruled out as tried removing all the bulbs....

[twosmoke300]

Ahh , sorry . No multiplex on that. Gear position bulbs staying on ?

[Bobthebeard]

Nope..... Nothing seems to be staying on. Just the relay clicking in when fuse replaced. Am baffled!

[brickwall]

Factory or after-market alarm?  I traced battery drain to a damp circuit board in the engine bay.

[twosmoke300]

Wonder if the aftermarket radio powering up the leccy aeriel motor / relay.

[vulgalour]

Mikeknight had an issue with the interior lights draining electricity.  He took all the fuses out and put them all back in and it cured the problem.

[Bobthebeard]

Mikeknight had an issue with the interior lights draining electricity.  He took all the fuses out and put them all back in and it cured the problem.

Hmmmm. Possibly worth re checking! Thanks.

[vulgalour]

If you can I'd check the fuses and the connectors for any sort of corrosion or fault.  One dodgy fuse can cause havoc.

[Bobthebeard]

Wonder if the aftermarket radio powering up the leccy aeriel motor / relay.

Could be onto something there twosmoke.... The leccy aerial does do a twitch when the fuse is removed/replaced!

[garethj]

Now you've isolated what's on that fuse, try disconnecting the clock and stereo one at a time.

[twosmoke300]

Or aerial motor is full of water

[HillmanImp]

Is the radio new? I had a problem with one trying to remember where it was on my MP3 player and constantly draining the battery. Had to remove the 'constant' wire to get rid of the memory and instead listen to the first few seconds or so of Move your body by Altern8 everytime I got into the car until I could put something else on.

[Bobthebeard]

Still struggling! Disconnected the electric aerial, radio and clock ( not sure about the clock TBH ) but still the relay under the dash can be heard to click in. The battery drain is still 350 milliamps..... Arrrghh.

[garethj]

Does the car run ok with that fuse taken off?  Even with the autobox controller thing unpowered?

 

If so, move the wire on the back of the fusebox for the clock and the radio to another fuse, and leave the offending one disconnected.  It could be a short circuit somewhere in the wiring that you'll just never find without a good wiring diagram and a shitload of patience.

[MikeKnight]

I had this problem when I put a cheap radio in, turns out even when "turned off" it was actually still on all the time. Cured it by putting a better radio in. Not saying you have a cheap radio.. just saying what happened to me.

 

The problem seems to stem from the fact this car doesn't have (nor ever appeared to have) a separate power on/off control for the radio power, which on other cars turns off the radio when you turn the ignition off, so with the better radio I got (some Sony DAB thingy) it had its own "power off after 30 seconds" mode. Without that, like I said, it appeared to turn my cheap radio off but actually wasn't at all.

 

[Edit: Another way to cure this without having to go get another radio is to install a switch on the dash which is a basic on/off for the radio power. That's if that is the cause of the problem, could be something entirely else!]

[Noel Tidybeard]

i'd be checking the bulkhead relay out

[dave21478]

Check the heater blower works on all speeds with that fuse out.

 

I think this is something to do with the battery drain on my 4x4....if I remove a certain fuse I hear a relay click behind the dashboard. With this fuse out the fan will not work on its highest speed...seems that the lower speeds run through a resistor pack but full blast is a straight feed via this relay. Feck knows why it is powered up all the time...im pretty sure it shouldnt be like that though.....either a short or I have screwed up the wiring somehow doing other work behind the dash.