We have a 2001 accord, 4 cyl, manual

Initial problem: Tail lights and signals not working. Replaced both fuses that were blown, on inside the drivers side and one in the passenger side. Signals sort of work now.. but now for the funky problems.

Funky problems: Right signal sticks on. When turning the right signal on the left tail light blinks also. when you turn the hazard lights on, the right engine cooling fan "flashes" on with the flashers. The left signal works fine. When i pulled the turn signal flasher relay from the box on the drivers side under the dash the light for the right signal stuck on for a while but eventually turned off. When I put it back in it went back to funky mode. When I spliced a ground into the right rear tail light it made no difference. When I pulled the fuse to the hazard lights from under the hood it made no difference in the signal issue it remained in funky mode although the cooling fan didn't flash along with the emergency flashers.

The ground strap from the battery to the body is good (is right off the neg post from the battery)

I was looking for a bad ground to the tail lights or something wrong with a flasher until I saw that the right engine cooling fan pulses with the flashers.. now that one threw me for a loop..

Possibly a bad fuse box under the hood? Or any other suggestions you honda folks can think of short of that task?

 

Hard to know the history of an older car, was there ever any damage along the right/pass side fender? There is a "bundle" (technical term there ) of wires that run along there.

For giggles, assuming the AC works, what happens when you turn on the AC - does the right/pass side act up?......wild shot on that one

 

Tested a little bit more this morning.. Merry Christmas to all btw.. No damage along the right side that we can detect and doesn't have a rebuilt title.

AC doesn't seem to affect anything when either on or off.

Better lighting today and saw that all tail lights blink dimly when the right signal is on as well as the low side of the left front signal light. All the lights on the dash blink as well as the indicator lights on the heating and ac switch.

When I turn the headlights on the right signal (both front and back) stick on and the dash right signal light goes on. When the lights are on and I signal right I can hear the flasher but nothing blinks on the right but left works fine. I took the right front signal bulb out and same result (that was the only place I could think of that the right signal and lighting system would be in close proximity other than somewhere in a bundle) Also jiggled the wire that fed the right front and no changes.

So kinda looking like I have power from the "small lights" #10 fuse on the passenger side to the right signal circuit so it would have to be somewhere after the flasher.

If that makes sense.. any thoughts on how to narrow the search area down a bit to at least either front half or back half of the car? Pulling the bulbs on either end has no effect.

If I were to throw out a guess I would say somewhere from the passenger side fusebox forward simply because those wires are exposed to the elements more than the back half are but if there is something that could be unplugged to narrow down a particular wire bundle it would be helpful.

Thoughts or other things to test?

UPDATE: I found a diagram of not quite the same year that almost makes sense. This right hand bundle feeds lights, signals, as well as the cooling fan. That side also feeds the small lights on the dash. So maybe the passenger side fuse box is bad? That would be the one place where circuits for fan, signals, dash would all come together.

 

Ok.. tracked it down a little bit further.. It is a front half issue.. I unplugged each of the plugs from the right hand fuse box one at a time to test and found that when one plug was removed the dash went back to normal and rear signals both worked properly.



With this plug pulled the rest of the car works alright. Appears this one feeds the headlights and front signals among a few other things. The plug does not appear to be corroded or burned at all.

Now the question is to figure out how to tell if it is in the fusebox or wiring bundle. I could test the pins with the electrical tester if I could find a diagram of what output pins are but have not run across it yet or a color coded diagram of wiring going forward to test for a short across the wires to lighting, signals, and cooling fan.

 

ok.. one more update then done messing with it for the day.. I threw a tester on the green plug that feeds the wiring bundle to do a quick test to see if that was an outgoing or incoming plug to the fusebox. I had power on the large yellow wire, the blue/white and the blue/red. There was also about 3v coming off one of the others. My thought was to eliminate the fusebox as an issue if there were no incoming wires to it. That test was done with the ignition on.

Also noted that the right cooling fan comes on about half speed when parking lights are on and sounds like full speed with headlights on. I did throw a ground on the plug to that fan and it made no difference. It is possible the fan issue has been there before but never was noticed. But if all these are the same root cause I am now leaning towards fusebox shorted somewhere feeding power across several lines.

Thats all I know at this point.. any other great informed guesses or things that I could test to narrow it down further?

 

From that plug, look to see if you find a GRN/YEL wire.....this should be the power to the right front turn lights....if you "de-pin" that wire from the connector what happens. Now there might be two of them (don't have a good diagram of that connector), if so one will be to the front and the other to the back.

 

Don't have a Grn/Yel on that plug. Will get a pic of the plug hopefully tomorrow if it stops snowing so hard. Good thought though.. I looked quite a bit for a good diagram of that plug with the pinouts but have not found one yet. Hopefully snow will let up soon.

 

Ok.. final solution was that it was a bad passenger side fusebox. Finally got down to the pull your own parts lot and grabbed one. Scored a distributor because I have a check engine light for the tdc sensor in the distributor and also found a good heater control switch for backup.. bonus.

Replaced the passenger side fusebox in 15 degree weather and all works great now. And guess what... no need for the distributor because apparently the problem with the TDC sensor was fixed with the fuse box fix also.

So now all lights work right and no check engine light on the dash! I would have never tracked that sensor problem back to the fusebox so suppose all in all it was good that it failed further.

Thank you much for your help in troubleshooting it and who knows. Someone else might run across a similar problem with the check engine light or the goofy lighting things that were going on and stumble across this thread.

 

Glad you got and a BIG THANKS for coming back with an answer. Too many time we never know the end of the story.

 

Agreed. It seems weird that a fuse box would just up and quit like that though. I haven't posted anything in this thread, as I had no idea on where to start on an oddball problem, but I've been following it to see if you'd find a solution. Congrats. Now go have a cold one, you earned it.