Parking light electrical problem

[PreludeFlie]

Have a 1991 Prelude and it does not charge my battery when I have my parking light on. When I have my lights off the battery charges. Anyone have ideas on what it can be?

[spiffyguido]

Do you mean that your battery warning light comes on when you turn on your parking lights?

[PreludeFlie]

Yes, but only after the juice from the battery is gone. When im driving with the parking lights on, it seems like the car starts using the charge from the battery instead of the alternator. Once the battery has lost most of its charge, THATS when the battery light turns on.

On another note, one of the headlights has come off the hinge, so it doesnt come up when lit.
Would this be causing a short?

[spiffyguido]

There could be a short due to the broken headlight, especially if this malfunction was caused by a collision and some wires were harmed. You could have a look there to see if anything looks like it could be shorting out.

What it sounds like to me is that your charging system isn't able to keep up with too many electrical things turned on at once, indicating a weak alternator. You may get similar behaviour if you turn on the rear defogger for example. You may want to try this.

Have you tested your alterator recently?

[PreludeFlie]

The alternator, battery and battery posts are new.

I thought it may have been that I bought a bad alternator so I drove back to the auto store and they tested both the battery and alternator. They both are good. During the daytime, I tested out the car by turning on the defrost, heater and radio all at once and the battery still took charge. Thats why i have pinpointed the problem to be with the lights.

Could the on/off light switch be faulty? Its kinda rough when switching from parking lights to headlights.

[spiffyguido]

It could be, but I don't see how that switch could fail in such a way to cause a power drain. Have a look, but I suspect that as you chase the wires you're more likely to find the problem somewhere else. There has got to be a short somewhere, or something else that is causing a power drain. If you are able to isolate any circuits, it might help you find the trouble area faster.

I know how frustrating this must be. Electrical problems are the worst kind.

[PreludeFlie]

Could it be that the belt is not tight enough? I changed the alternator myself about 1.5 months ago.

PS. Thanks in advance for replying. Atleast I know that I can get some feedback on my Prelude here.

[spiffyguido]

If the belt was loose, you'd likely be able to hear it squealing like crazy. I'd sooner suspect that the alternator itself is bad, but your test with the rear defogger should have ruled that out. If you're at all interested in alternator testing (which I know you've already done), this thread is interesting:

viewtopic.php?f=4&t=609

If I were you, I'd continue chasing the circuits to see if you can find a potential area for a short. It sounds like you can isolate the problem to the lighting circuit, which narrows things down a lot. The electrical diagrams in the back of the manuals (in the manuals section of this site) can be very helpful.

[PreludeFlie]

Big thanks looking out for a fellow Prelude Driver!

I fixed the loose headlight as well as re-tightened the alternator belt. Seems like that was all it needed.

Again, big thanks.

Prelude Flie

[spiffyguido]

Happy to help.

Come back with any other questions you have, post up a pic of your lude in the Prelude Pictures topic in the "Just for Fun" forum, and be sure to tell your friends about preludedriver.com

[RedRacer]

Spiffster to the rescue, eh? Good job Spiffy!

Glad you got things working right again, PreludeFlie! Very cool for you! And didn't cost a penny! You're very welcome and do come back and contribute, hang out, whatever. Share the site with those you know. Word of mouth is a good thing. We want and need more members so as a collective we can give good advice and help out fellow Prelude owners and drivers.

Just to add, when having an alternator checked at places like AutoZone, PepBoys, etc. their method of checking is not the most accurate. If there is a bad diode in the alternator, their machines will usually NOT pick that up. Bad alternator diodes reduce alternator output current & voltage and are overlooked a majority of the times alternators are tested, leaving people in a lurch because they've checked everything and everything seems to be OK, but things still aren't working as they should.

Always a good idea to pull the alternator off the car and take it to a reputable automotive electric business and let them do a thorough check on the unit.

Just FYI.

[PreludeFlie]

Thanks for the 411! Ill be sure to keep that in mind.

My next little project is replacing the driver side calipper. Last time I did the front brakes the driver side was completely wasted and the pass. side still had plenty of meat left.

On that note, how diffrent are the front brakes from the back brakes?

[spiffyguido]

Functionality wise, the back brakes are very similar to the front, but size wise, they vary tremendously. The rotors, pads and calipers in the front are far bigger than in the back.

[RedRacer]

I was waiting on Spiffy to comment on the brake question. I don't know 3rd gen's as well, didn't want to mis-speak.

I know on the 4th gen, the only difference is size variance between front and rear. Front brakes take on way more of the stopping task than the rear.

Also, on the 4th gen you have to have a special tool to press the caliper piston back into place. The rear caliper piston on the 4th gen screws in and out of place. Not just pressure fitting. The piston side of the caliper has a X grooved into it. You can use a large, flat-head screwdriver or needle nose pliers in the middle of the X to get a hold and then screw the piston back into place. Or, you can get the Honda tool if you prefer. Easier to use the screwdriver in my opinion.

[spiffyguido]

The rear caliper piston on the 4th gen screws in and out of place. Not just pressure fitting. The piston side of the caliper has a X grooved into it. You can use a large, flat-head screwdriver or needle nose pliers in the middle of the X to get a hold and then screw the piston back into place. Or, you can get the Honda tool if you prefer. Easier to use the screwdriver in my opinion.

Same on 3rd gen.